The Universe is 13.73 +/- .12 billion years old!

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Happy birthday, Universe!

Kinda. It’s not really the Universe’s birthday, but now we do know to high accuracy just how old it is.

How?

NASA’s WMAP is the Wilkinson Microwave Anisotropy Probe (which is a mouthful, and why we just call it WMAP). It was designed to map the Universe with exquisite precision, detecting microwaves coming from the most distant source there is: the cooling fireball of the Big Bang itself.

New results just released from WMAP have nailed down lots of cool stuff — literally — about the Universe.

I am about to explain the early Universe to you. I’ll be brief, but if you want to skip to the results, then go ahead.

Here’s the quick version: the Big Bang was hot. The Universe itself expanded outward from a single point — actually, it’s space itself that expands, not the objects in it — and like any expanding gas it cooled. After about a microsecond, it had cooled enough for protons and neutrons to form. Three minutes later (yes, just three minutes) it had cooled enough for protons and neutrons to stick together. Hydrogen, helium, and just a dash of lithium were created, and these would be the only elements for some time (hundreds of millions of years, in fact). The Universe was a thick soup of matter and energy.

It kept expanding and cooling. At this point, it was opaque to light. A photon couldn’t travel an inch without smacking into an electron and then getting sent off in some other random direction. However, after a few hundred thousand years, an amazing thing happened: neutral hydrogen could form. Before this point, the Universe was still too hot; as soon as an electron bonded with a proton, some ultraviolet photon would come along and whack it off. But at that golden moment the cosmos had cooled off enough that a lasting atomic relationship was in the offing. Neutral hydrogen was born. At that moment — astronomers call it recombination, which is a misnomer, since it was the first time electrons and protons could combine — the Universe became transparent; without all those pesky electrons floating around, photons found themselves free to travel long distances.

It’s those photons WMAP sees. After 13.7 billion years, the expansion of the Universe has cooled the light, stretched its wavelength from ultraviolet to microwave. Another way to think about it is that the temperature associated with each photon went from thousands of Kelvins down to just a few, less than 3, in fact. That’s -270 Celsius, and -454 Fahrenheit.

Brrrr.

That light emitted just after recombination tells us a vast amount about the Universe at that time. By carefully mapping the exact wavelength of the light and the direction from where it came, we can tell the density and temperature of the matter at that time. Incredibly we can also tell how much dark energy there was, and even the geometry of the Universe: whether it is flat, open, or closed.

All this, from the dying glow of the Big Bang itself.

WMAP Results

A lot of this information was determined a while back, just a couple of years after WMAP launched. But now they have released the Five Year Data, a comprehensive analysis of what all that data means. Here’s a quick rundown:

1) The age of the Universe is 13.73 billion years, plus or minus 120 million years. Some people might say it doesn’t look a day over 6000 years. They’re wrong.

2) The image above shows the temperature difference between different parts of the sky. Red is hotter, blue is cooler. However, the difference is incredibly small: the entire temperature range from cold to hot is only 0.0002 degrees Celsius. The average temperature is 2.725 Kelvin, so you’re seeing temperatures from 2.7248 to 2.7252 Kelvins.

3) The age of the Universe when recombination occurred was 375,938 years, +/- about 3100 years. Wow.

4) The Universe is flat.

5) The energy budget of the Universe is the total amount of energy and matter in the whole cosmos added up. Together with some other observations, WMAP has been able to determine just how much of that budget is occupied by dark energy, dark matter, and normal matter. What they got was: the Universe is 72.1% dark energy, 23.3% dark matter, and 4.62% normal matter. You read that right: everything you can see, taste, hear, touch, just sense in any way… is less than 5% of the whole Universe.

We occupy a razor thin slice of reality.

There are other important things that have come from the WMAP data, and if you’re interested, you can read all about them on the WMAP site and in the professional journal papers.

But if you only want to peruse the results I’ve highlighted here, that’s fine too. But remember this, and remember it well: you are living in a unique time. For the first time in all of human history, we can look up at the sky, and when it looks back down on us it reveals its secrets. We are the very first humans to be able to do this… and we have the entire future of the Universe ahead of us.

March 5th, 2008 6:12 PM by Phil Plait in Astronomy, Cool stuff, NASA, Science | 249 comments | RSS feed | Trackback >

249 Responses to “The Universe is 13.73 +/- .12 billion years old!”

  1. 1.   shane Says:

    Does WMAP data go any of the way to hypothesising just what dark energy and dark matter are? I mean does it firm up any particular theory or does it just quantify just how much of this stuff there is?

    Great post BA. Thanks.

  2. 2.   Shane Killian Says:

    Wow. I am in awe. This is probably one of the biggest days in the history of science, up there with the confirmation of heliocentricism and the moon landings.

    And yet, few people will even hear about it. More’s the pity.

  3. 3.   Jeffersonian Says:

    Phil, this is a well-written entry.

    I llllllllike it

  4. 4.   Jeffersonian Says:

    Phil, this is a well-written entry.

    <Tom Brokaw>I llllllllike it</Tom Brokaw>

    (I wanted to see if this would parse correctly the second time)

  5. 5.   Angrynight Says:

    I was just listening to Fraiser Cane and Dr. Pamela Gay discussing WMAP in the Astronomy Cast. Their explanation is excellent and it’s definitely worth linking to:

    http://www.astronomycast.com/astronomy/ep-78-what-is-the-shape-of-the-universe/

    However, I was also reading Scientific American’s article on the end of cosmology as we know it, and it makes me wonder what pieces of the puzzle we’re still missing. Still, all of this is very exciting.

  6. 6.   drew terry Says:

    I have yet to get a straight answer to these two questions:

    1. How long did the big bang take for expansion?

    2. Are there any scientific experiments with results which prove the assumptions about expansion?

    FYI, I am not a right-wing christian fundamentalist or anything of the sort.

    I just want to know what we think we know, versus what we know by proof.

    Thanks!

  7. 7.   Jewel Says:

    It’s good to be alive. I don’t understand how people can think that science takes away the magic, so to speak. Stuff like this just makes me more in awe of it all.

  8. 8.   Chris Says:

    I find it amazing that we can pinpoint the age of the universe with that much accuracy! It is a pity this would at best be a footnote in the mainstream news.

  9. 9.   Seamyst Says:

    Wow. This is amazing and awe-inspiring.

  10. 10.   Blu-Ray-Ven Says:

    “The Universe itself expanded outward from a single point, and like any expanding gas it cooled”

    wouldent that make our universe a bubble, but every time i hear physisits talking about the cosmos they say its flat or curved, or wrinkled. whatever. how can bubble expanding evenly in all direction be flat?!? then they go into the whole “4th dimention” thing which makes my head want to pop from an overload

    finite an unbounded or infinite and closed. admit it our universe is a bubble, like a baloon, exapanding in all direction evenly. would that not make it a sphere?

  11. 11.   MercuryBlue Says:

    “The age of the Universe when recombination occurred was 375,938 years, +/- about 3100 years.” Sig fig error, anyone?

    Other than that…coooool.

  12. 12.   Blu-Ray-Ven Says:

    shame on me for not readin the article thourghly,

    “The Universe is flat”, huh, like a piece of paper!?!

    again i cant wrap (haha) my head around that idea, no matter how much i read about it. its a bit counterintuitive considering i can look out into the sky at all possible direstion in 3 dimensions. never mind. ill go back to playing freecell

  13. 13.   freelunch Says:

    I’m a bit baffled by the choice of words in stating that the ‘universe is flat’. Clearly it is not, so what exactly is the cosmological definition of ‘flat’. I read the NASA article and I think they are saying that the universe is well-approximated by Euclidean space in its behavior, but I’m not certain that is what they are trying to tell me.

  14. 14.   Christian X Burnham Says:

    My favorite result is that the universe is flat (to within +/- 2%). A flat universe is consistent with an infinite universe. That really is something to think about.

    The world really is flat! Say it with pride.

    (Another Digg and Reddit worthy blog entry.)

  15. 15.   13.73 billion years, plus or minus 120 million years | Geoff Arnold Says:

    [...] to this fascinating piece over at the Bad Astronomy Blog, that’s the age of the Universe. And furthermore… The [...]

  16. 16.   The universe: large, flat, and mostly dark « Science Notes Says:

    [...] blog reports on a five-year analysis of the cooling remnants of the Big Bang from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP). Posted in [...]

  17. 17.   Thanks to Phil Plait for breaking it down — anti-theism.net Says:

    [...] Bad Astronomy Blog » The Universe is 13.73 +/- .12 billion years old! [...]

  18. 18.   Mercurious Says:

    Blu-Ray-Ven: Here is a link that explains what a “flat” universe means.

    http://www.newton.dep.anl.gov/askasci/ast99/ast99517.htm

    You’ll have to scroll down to the bottom of the page to get to it. Basically it says in a “flat” universe 2 parallel lines will always remain the same distance apart. In an elliptical universe, straight lines would eventually meet; in a hyperbolic universe, parallel lines would have one region of closest approach, and diverge in both directions from there.

  19. 19.   Rick Schauer Says:

    Hopefully that will end this 2008 crap…when can we all start writing 12,000,002,008?

  20. 20.   BB Says:

    Alright, so the universe is flat, but that leaves me with one question:
    The universe being flat means that space literally goes on forever, and doesn’t curve in on itself like it does with a closed universe. So there’s an infinite amount of space. Is that infinite amount of space populated by a finite or infinite amount of matter?

    If there is a finite amount of matter, would that mean that there would actually be some “center” of the universe, approximately at the center of all of that matter, and at the point at which the big band originated? I’m aware that it’s space itself that is expanding and not that matter itself is expanding away from any particular point, but either way if you reverse time, any finite amount of matter should eventually collapse into a point somewhere in space.

    And if the amount of matter is infinite, does that mean that the big bang actually occured everywhere at once, and the universe didn’t start out as a point but rather an infinitely large singularity which then expanded and simply became less dense?

    I also had another, slighly unrelated question: Any light which is emitted by an object that is more than about 13 billion light years away from us will never reach us due to the expansion of space. (Yes I know we can see objects which are further away because they were close enough when they actually emitted the light, but I’m talking about anything emitting light right now). I’m not sure of the exact number, but it was very close to 13Gly and was calculated from the Hubble constant which had a fairly large error anyway. My question is, is it merely coincidence that this number happens to be so close to the age of the universe (albeit in different units)?

  21. 21.   John Armstrong Says:

    The universe is flat within a 2% margin of error. But “flat” is such a special term that that margin of error makes for radically different cosmology and physics. To state that it’s flat without the margin of error caveat is incredibly misleading.

  22. 22.   shane Says:

    BB wrote: Alright, so the universe is flat, but that leaves me with one question:
    The universe being flat means that space literally goes on forever, and doesn’t curve in on itself like it does with a closed universe. So there’s an infinite amount of space. Is that infinite amount of space populated by a finite or infinite amount of matter?

    Please correct me if I’m off base but it may be that space and matter, ie. the universe, is finite but is expanding infinitely.

    To infinity and beyond…

  23. 23.   Ivan Says:

    Phil wrote: “The Universe itself expanded outward from a single point”

    I’m not a cosmologist, but this sounds like a schoolboy howler to me. Space itself is doing the expanding, so it’s nothing like an ordinary explosion. See

    http://en.wikipedia.org/wiki/Metric_expansion_of_space

  24. 24.   Ivan Says:

    Oops, I meant to say in particular that there is no center point of the expansion.

  25. 25.   Ivan Says:

    BB: There are several possibilities for a universe which has a finite amount of space in it but no center point and no edge.

    It’s easiest to start with a 2-dimensional example– take the surface of a sphere, which has finite area, but no center point (remember, we’re only considering the surface of the sphere) and no edge.

    This is a bit abstract: mathematicians like to think of these things (they call them manifolds) without requiring them to be embedded in a larger space. (I know, it seems impossible to imagine the surface of a sphere without thinking of it as embedded in 3-dimensional space.)

    Another 2D example is the torus (the surface of a doughnut). This one is interesting because it can be flat (unlike the sphere), but unfortunately a flat torus can’t be embedded in 3D Euclidean space. However, the flat torus is actually quite easy to imagine: think of the video game Asteroids, where your ship wraps around to other side of the screen whenever it hits the edge of the screen.

    There’s also a 3D version of the torus, which you can think of as the interior of a cube, where whenever you pass through one of the walls of the cube you reappear at the opposite wall.

    And there are many other 3D manifolds, most of which are a lot harder to explain…

  26. 26.   Tom Marking Says:

    I’ve always been curious about what the exact meaning of the 13.73 billion years is or whatever other number you’d care to choose. Is that the elapsed time on some hypothetical clock that existed from the beginning? Of course, such a thing is impossible, but if some type of clock could have been created at the same instant as the Big Bang what would its reading be now?

    Consider what happens if we drop an object which emits a radio pulse every one second into a black hole. At the beginning our radio receiver picks up the pulse every second but as the object gets closer and closer to the event horizon the pulses get more and more spread out – once every minute, once every hour, once every day, etc., etc. From the point of view of the outside observer the object takes an infinite amount of time to fall through the event horizon.

    Doesn’t the same thing apply here with the universe as a whole? The early universe had severe space-time warpage which would have caused time to slow down. Doesn’t that mean from the perspective of general relativity the elapsed time back to the original singularity of the Big Bang is infinity? Or does it all change since we are inside the universe and there is no outside observer? Can someone clarify this paradox for me.

  27. 27.   Ivan Says:

    Oh, and this wikipedia article looks pretty good:

    http://en.wikipedia.org/wiki/Shape_of_the_Universe

  28. 28.   Tom Marking Says:

    “So there’s an infinite amount of space. Is that infinite amount of space populated by a finite or infinite amount of matter? ”

    If it’s truly a perfect Euclidean space with no overall curvature then a finite amount of matter would have to have a particular center of mass. So in such a universe you actually could have a point that was the real center of mass. Now, whether you could deduce where it was only from data from the observable part of your universe is a different story.

    And unless the matter in the universe is moving quickly enough it will eventually tend to accumulate at that center. That’s what Newton feared and that’s why he speculated that we live in an infinite universe with an infinite number of more-or-less evenly spaced stars.

  29. 29.   jmil Says:

    Sorry for the newb question:

    So if the universe is “flat,” meaning it’s angular measurements have lines that stay parallel to each other, (assumedly in all 3 dimensions) wouldn’t that make our universe more like an expanding box (or quadrilateral maybe), except with invisible edges?

    If not, is it possible to interpret our flat universe as a 3D representation? Showing it as a simple plane just seems to confuse (at least) me.

  30. 30.   Ivan Says:

    Tom Marking wrote: “If it’s truly a perfect Euclidean space with no overall curvature then a finite amount of matter would have to have a particular center of mass.”

    Not true. The flat 3D torus which I described earlier has no center, and every point is the same as every other point. (The center point of the cube model is not special, because the walls of cube aren’t boundaries; opposite walls are “glued” together.)

  31. 31.   Adam Says:

    This stuff is too hard to understand. God did it, case closed.

    Just kidding, great post. All kinds of good information I need to get up to speed with.

  32. 32.   The Bad Astronomer Says:

    Ivan, yeah, you have a point. I should have left off the word “outwards”. It’s not really wrong; the Universe is expanding outwards, as every point in the Universe measures it. But in that context and phrased that way, it could easily be interpreted as outwards from a point. I’ll fix it now.

  33. 33.   Ivan Says:

    jmil: Unfortunately it’s difficult to describe the flatness of space without resorting to 2D analogies. The easiest to understand compact flat 3D manifold is the flat 3-torus, which you can imagine as the interior of a cube with each pair of opposite walls glued together. I’ve been trying to find a good picture of this, but no luck so far…

  34. 34.   Ivan Says:

    Thanks for changing that, Phil. I just tend to worry a lot about misconceptions that are suggested unintentionally.

  35. 35.   Mercurious Says:

    If you really want to tie your brain into knots… Once you think you get a grasp on what a “flat” universe is, throw in the Einsteinian warping of space/time due to gravity. I once heard of a way to imagine the expansion of the universe as compared to raisin bread. As the bread cooks it expands. The raisins move farther away from each other but don’t actually move.

  36. 36.   Dan Gerhards Says:

    Answering drew terry:

    1. How long did the big bang take for expansion?
    The big bang was the beginning of the expansion of the universe, but the expansion is still going today. That’s as straight an answer as you can get.

    2. Are there any scientific experiments with results which prove the assumptions about expansion?
    Several, but there is one big one. Back when most astronomers mocked the big bang supporters, they realized that the big bang would have created 3 Kelvin radiation filling the sky. Nobody knew that radiation actually *existed* back then, because they couldn’t detect it. It was eventually discovered by accident, pretty much proving the big bang people right. If it *hadn’t* been there, they would have been proven wrong. There have been other experiments that support the expansion, but that was the best. (There are no experiments that refute it either. That’s important, too.)

  37. 37.   Ivan Says:

    Now I remember where I’ve seen good pictures of the 3-torus. Google “Jeffrey Weeks” and/or “The Shape of Space”. He’s got some great stuff, including a book, videos, and even software to let you fly through the models.

  38. 38.   Richard Wolford Says:

    Wow…this is a freakin’ cool blog entry. How in the world can anyone oppose science so strongly when we discover things like this. It is truly a great time to be alive.

  39. 39.   madge Says:

    Great postin Phil!
    I’m just pleased the results have been published in time for me to include them in my final submission for my cosmology course!
    It’s at time like this that science just makes your jaw drop!
    Happy Birthday Universe and well done us for working out how many candles to light and what size and shape of sweater to knit!
    Awesome!

  40. 40.   BolingbrookPete Says:

    Wow. Just…Wow.

    This one really impacted me. I guess I had grown comfortable with the inflating balloon analogy. Now that’s not it at all.

    That’s the inspiring part of science, always challenging your view of everything around you.

    Thanks Phil

  41. 41.   Almo Says:

    Great stuff Phil!

    I’m having slight difficulty deciding how “WMAP” should be pronounced; for some unexplainable reason I think of it as [We-map], and Double-You-map sounds a bit clumsy in comparison :S

    Can someone refer to this?

  42. 42.   Ambarussa Says:

    (Please, forgive my English)

    I like your post, but there is one thing I can’t understand:

    If the dark energy is forcing space to expand, doesn’t that mean that the Universe is open and not flat?

    I hope you get what I mean. Thanks.

  43. 43.   Cusp Says:

    Sorry Phil – But space is not a thing and it does not expand. While you can talk about expansion of space in a metric sense, saying “space expanding” moves galaxies apart is incorrect.

  44. 44.   Cusp Says:

    [ps - the wmap result is great]

  45. 45.   Overstroming Says:

    So, is it true to say that all the basic atomic building blocks that I’m made from, and my desk and laptop and everything around, are all 13.7 billion years old?
    It would be amazing to know the ‘life story’ of a proton or electron, they’ve been on a wild trip.
    Truly mind blowing.

  46. 46.   quasidog Says:

    I don’t think of space as being ‘nothing’. It is clearly something which makes it a ‘thing’. True nothingness has no dimension, and cannot be imagined in any form; as it is nothing.

    Space however has dimension. If I take a 1 meter cube of space, I can’t have a cube of nothing, due to the fact I can measure it. If you want nothing, you must remove its dimensions. Doing so shrinks it right down to; not even a pinpoint, but nothing. You can’t even imagine nothing, due to your trying to imagine it, making nothing, something.

    Sure, its not an aether, but it seems to warp under gravitational influence. For something to warp, it has to be a ‘thing’. ( this assumes Quantum Gravity is not the cause)

  47. 47.   Bryan Østergaard Says:

    the entire temperature range from cold to hot is only 0.0002 degrees Celsius. … so you’re seeing temperatures from 2.7248 to 2.7252 Kelvins.

    I’m either confused by this statement (entirely possible due to lack of coffee) or the numbers above are slightly wrong. Cool article though.

  48. 48.   Cusp Says:

    >Sure, its not an aether, but it seems to warp under gravitational influence. For something to warp, it has to be a ‘thing’. ( this assumes Quantum Gravity is not the cause)

    This is incorrect. If you don’t believe me (who has written several papers on the issue) how about Steve Wienberg?

    ‘Good question,’ says Weinberg. ‘The answer is: space does not expand. Cosmologists sometimes talk about expanding space – but they should know better.’

    Rees agrees wholeheartedly. ‘Expanding space is a very unhelpful concept,’ he says. ‘Think of the Universe in a Newtonian way – that is simply, in terms of galaxies exploding away from each other.’

    From: http://www.newscientist.com/article/mg13818693.600-all-you-ever-wanted-to-know-about-the-big-bang—-everyweek-questions-about-the-big-bang-flood-into-the-new-scientist-officesowe-thought-it-was-about-time-to-let-some-experts-loose-on-the-subject-.html

  49. 49.   John Phillips, FCD Says:

    @Overstroming, no, only Hydrogen, Helium and some lithium were initially formed from what was available after the big bang. All other elements are formed from one aspect or another of a star’s ‘life’ cycle. Which elements are formed is mainly dependent on the size and type of star and thus are still being formed today.

  50. 50.   BB Says:

    [i]Ivan: BB: There are several possibilities for a universe which has a finite amount of space in it but no center point and no edge…[/i]

    Yes, I’m aware of that. But that only applies to a universe with a closed geometry. According to WMAP, space is flat which means it extends infinitely. In a closed universe if you travel in one direction long enough you’ll end up right back where you started just as you would on the earth or in Asteroids. In a flat universe if you travel in one direction, you just keep going forever. It’s like a piece of paper that just extends infinitely in every direction. It has no curvature, therefore there’s no way by travelling in a single direction you could ever return to your starting point. My point is that a flat universe is infinite, not finite as you talked about in your post.

    However, within this infinite amount of space there could be either a finite or infinite amount of matter, and I’m asking which, because it makes a big difference to how we look at the universe.

  51. 51.   David Says:

    @BolingbrookPete
    The balloon idea isn’t entirely wrong. As I understand it, something akin to pennies on the surface of a balloon can be considered a model of the universe (for expansion, not shape) because it is finite, yet unbounded and the farther away something is the faster it moves away.
    Someone correct me, as I’ve undoubtedly made a mistake.

  52. 52.   doug livesey Says:

    “as soon as an electron bonded with a proton, some ultraviolet photon would come along and whack it off”

    Man, and you tell us to keep the comments clean …

  53. 53.   Overstroming Says:

    @John Phillips, FCD, thanks but I meant that all matter that’s around today is made from the same matter, reconfigured or otherwise, that was created then. Electrons, protons etc can be arranged into various atoms but they themselves are as old as the universe.
    That’s my pretty inexpert understanding anyhow -
    Martijn.

  54. 54.   Brent Says:

    Sorry for the lame question, but can someone tell me the basic method by which measuring these microwaves can tell us when the big bang happened?

    I skimmed the article looking for a layman’s explanation but didn’t notice one. Sorry if I just missed it.

  55. 55.   Tom K Says:

    “What they got was: the Universe is 72.1% dark energy, 23.3% dark matter, and 4.62% normal matter.”

    Shouldn’t that 4.62% be referred to as “unusual matter” or “rare matter”, since it’s clearly in the minority?

  56. 56.   Tom Marking Says:

    “Not true. The flat 3D torus which I described earlier has no center, and every point is the same as every other point. (The center point of the cube model is not special, because the walls of cube aren’t boundaries; opposite walls are “glued” together.)”

    The universe you’re describing is not globally flat. It has space-time warpage, actually rather severe space-time warpage connecting the opposite walls of the cube together. It is only “flat” in between the walls. Usually the terms “flat”, “open”, “closed” are used to refer to the overall amount of space-time warpage in the universe and not to some particular region within the universe.

  57. 57.   IRONMANAustralia Says:

    I guess that means Kent Hovind is only wrong by 13.729994 billion years. Somehow I didn’t expect him to get so close.

    To all you people who work in the field of astronomy, I’ve been dying to ask:

    Did you ever in your wildest dreams think you would know the answers to questions like this, (the age/geometry/nature of the universe, etc..)? I mean before you knew these experiments were on the drawing board, and even though we’ve known for a long time some of the possibilities.

    Or did you think these answers were unlikely to be answered within your lifetime, or perhaps were intrinsically unknowable?

  58. 58.   Doc Says:

    @David

    I’m really confused here, and I thought I understood all the “geometric” concepts of cosmology.

    How can a flat space be both finite and unbounded? If the universe is flat, then won’t there be an edge to it somewhere?

    Maybe it really is spherical, but the mass of the universe occupies only a small portion, and the curvature is too small for us to observe (somewhere in that odd 2% margin of error).

  59. 59.   Doc Says:

    Just thought of something weird.

    If the universe is finite and flat, and shaped like a raisin, then the wrinkles might explain the strange distribution of the background radiation. The bright and dim points are where the wrinkle is farther from or closer to us (or maybe the other way around).

    I’m still envisioning something like a Star Trek episode where the ship reaches the edge of the universe …

  60. 60.   MartinM Says:

    The universe you’re describing is not globally flat.

    You’re confusing intrinsic and extrinsic curvature. The torus is intrinsically flat, but to embed it in a 3D euclidean space introduces extrinsic curvature. No measurements made completely within the surface of the torus will produce any evidence of curvature, such as triangles whose angles don’t sum to 180 degrees.

    How can a flat space be both finite and unbounded? If the universe is flat, then won’t there be an edge to it somewhere?

    Think ‘Pacman.’

  61. 61.   Barton Paul Levenson Says:

    drew terry writes:

    [[How long did the big bang take for expansion?]]

    It’s still expanding.

  62. 62.   Barton Paul Levenson Says:

    That being said, thanks, Phil, for posting this. This is very, very cool stuff. Is there a single article which summarizes all these findings?

    I hope, for philosophical reasons, that the amount of matter in the universe turns out to be finite. But I don’t see how we could even test the question.

  63. 63.   zer0 Says:

    Lots of really cool information here, I’m definitely gonna have to spend some more time studying this flat geometry of space. While it’s nice to be able to put a “timestamp” on the Universe, is it not a rather trivial one? Why are we putting the age of the entire Universe in terms of Earth years? Is there no better standard? I understand that by using Earth years it makes it easier to comprehend in the sense of time that we use everyday, but the rest of the Universe hardly cares if the Earth goes around Sol in 365.25 days.

  64. 64.   Hannu Siivonen Says:

    “but now we do know to high accuracy just how old it is.”

    That’s funny. High accuracy is actually 120 000 000 years :-) Oh, the relativity of things…

  65. 65.   ioresult Says:

    2.7252-2.7248=0.0004. You mean it ranges from 2.7249 to 2.7251, yes?

  66. 66.   Greg Says:

    I know it’s picky but this IS science. Shouldn’t it be the Universe is 13.73 billion CE years old? CE standing for current earth. From our frame of reference (time, space) it may seem obvious we are talking about Current Earth Years but change trhe reference point and the number becomes meaningless. It’s meaningless without a stated reference point anyway.

  67. 67.   Doc Says:

    zer0,

    “Why are we putting the age of the entire Universe in terms of Earth years?”

    Because it’s a convenient unit? If we measured it in galactic rotations or used the Mesoamerican Long Count then we’d still have to convert it to some other unit to make sense out of it.

    I suppose we could define the Schlomowitz Unit as being equal to the current age of the universe. Then we could say that the universe was exactly 1 Schlomowitz Unit old. This would have the benefit of being infinitely precise, but it wouldn’t be very useful.

  68. 68.   Doc Says:

    Greg,

    I believe that CE stands for “Common Era”, not “Current Earth” (unless there’s a new astronomy term I wasn’t previously aware of).

  69. 69.   Torbjörn Larsson, OM Says:

    @ drew terry:

    The answers to your questions is right in the post! The current age (of the still expanding universe – big bang is the still ongoing expansion) and the very best experiments behind the age estimate. (Several experiments are combined, see the linked references.)

    @ BB:

    Any light which is emitted by an object that is more than about 13 billion light years away from us will never reach us due to the expansion of space. [...] My question is, is it merely coincidence that this number happens to be so close to the age of the universe (albeit in different units)?

    I’m not a cosmologist, but coincidence I think not. AFAIU the cosmological clock discussed is measured by following the expansion as a comoving observer (comoving coordinates). The size of the observable universe and its cosmological age are intimately related. As the universe expands and ages we can see further back and further out.

    @ Tom Marking

    Is that the elapsed time on some hypothetical clock that existed from the beginning?

    See my comment on the cosmological clock above. This clock is correlated with the temperature of the CMB radiation that WMAP measures. So it is a very real clock.

    The early universe had severe space-time warpage which would have caused time to slow down.

    Relative to what? We can only measure time by observing clock and comparing them. If all clocks are slowed we don’t measure any difference.

    As you suggest, that we live inside the universe makes a difference. There is no outside to compare with.

  70. 70.   Mark Says:

    Hey Phil,
    Another great post! I’ve always thrilled at the precision of these numbers ever since they were first published. I mean, it doesn’t get much cooler than having such an exact estimate of the universe’s vital stats!

    One thing though; I think your calculator may need new batteries. If the entire temperature range from cold to hot in the CMB is 0.0002 K, than we’re actually talking about a range from 2.7249 K to 2.7251 K rather than from 2.7248 K to 2.7252 K.

    But whose quibbling :-) After all, it was only the most precisely measured black body spectrum in nature, ever.

    Keep up the good work, bro!

  71. 71.   Resultaten van vijf jaar WMAP zijn bekendbijAstroblogs Says:

    [...] indrukwekkend lijstje van resultaten die de WMAP geboekt heeft. Wordt vast en zeker vervolgd! Bron: Bad Astronomy Blog + [...]

  72. 72.   SkepticTim Says:

    The question of space being flat confuses many people. First, locally, general relativity teaches that space is curved by mass – (mass tells space what to do, space tells mass how to move) – but on a cosmic scale the universe is spatially – note, spatially – flat. However, space-time is curved: flat space expands in the time direction making space-time curved. Think of space as a “slice” through space-time.

    Hope this helps explain, not increase confusion!

    Note that the “big bang” explains how the universe behaves (its a consequence of general relativity): it does not tell up anything about its origin. The fact that, when we extrapolate (always risky) “big bang” behavior far enough backward in time we get a singularity tells us that our familiar physics breaks down there: Hence, there is something incomplete about our knowledge of physics. This incompleteness is what M-theory, loop quantum gravity, etc. is all about!

  73. 73.   Torbjörn Larsson, OM Says:

    @ Cusp:

    But space is not a thing and it does not expand. While you can talk about expansion of space in a metric sense, saying “space expanding” moves galaxies apart is incorrect.

    Not if you are comparing different comoving frames, I think. You refer later to “Steve Wienberg” [sic], but in that article Steven Weinberg is discussing the universe as seen from a local comoving frame.

    That is why they call it relativity theory – physics looks different in different frames, precisely because there are universal laws and symmetries. It’s only if we use comparable frames it will be comparable results.

    He is also discussing the fact that reasonable GR solutions (i.e. low massenergy density) are locally flat, so there is no observable local expansion of space that rips small objects apart. Especially with local gravitation from masses warping space slightly to prevent that.

    So in the local comoving frame it makes much sense to use Weinberg’s model. Over proper distances – not so much.

    Btw, this article seems to suggest Weinberg uses non-conventional terms. And that “The issue of how to best describe and popularize the apparent superluminal expansion of the universe has caused a minor amount of controversy.”

    So I would give this description some leeway.

  74. 74.   Torbjörn Larsson, OM Says:

    Shouldn’t that 4.62% be referred to as “unusual matter” or “rare matter”, since it’s clearly in the minority?

    Don’t get me started on pesky historical accidents in science. Why should the SI mass unit be “kilogram” instead of “gram”? [Because of a political decision, that's why. Don't get me started on politics in science ... :-P ] Why does a theoretical current still, by historical definition, flow from a positive potential to a negative, when the later observation is that in the most usual physical current, electrons, particle flow goes in the reverse direction? Why is everyday “normal” matter suddenly rare?

    And so on and so pesky forth…

  75. 75.   Doc Says:

    “Hope this helps explain, not increase confusion!”

    Nope. Didn’t help.

    BA’s post said that the *universe* is flat – not local space. I assume that he meant that on a cosmic scale, the universe is not curved.

    I understand the balloon analogy (I read “Flatland” when I was very young), and I can understand a 3 dimensional space could seem to be flat to its inhabitants (”internally flat”) and still be warped around in higher dimensions as to have no edges (”externally curved” – note that in such a situation, the sum of the angles of a triangle would have more than 180 degrees, but no one would notice because the measuring sticks are also bent).

    What boggles me is the statement that the universe is flat (taken to meaning “externally flat”) and has no boundries. That does not compute. If the universe is warped around itself in higher dimensions then it’s not really flat – it’s spherical (or saddle-shaped, or whatever). If it’s really flat, then it must have edges – you can’t flatten a basketball without making an edge unless you warp space.

  76. 76.   Shopping Cart Software Says:

    Very interesting, It is nice to know the age of the universe. :)

  77. 77.   Bob Says:

    Couldn’t the universe be far older than this? This is only the light we can actually see and measure. What about the stuff that has already expanded out of our sight, over the universal horizon so to speak?

    The flatness of the universe has NOTHING to do with its 3d shape. Its just a concept that means two parallel lines will never meet, ever.

    Another concept to realize is that not only is everything IN the universe expanding, the actual universe itself is expanding but this expansion is not something we can measure since we are inside the frame of reference. Only someone outside of our universe could measure that expansion.

  78. 78.   schenn Says:

    “The universe is flat” 1000 years ago, our best scientific guess was the world was flat. That should be changed to “our percieved universe is flat” as “the universe is flat” excludes a lot of quantum theories

  79. 79.   Christian X Burnham Says:

    Wow. Judging by the votes, it looks like Digg users are significantly more interested in astronomy than Reddit users.

    All my Reddit submission managed to generate was a few sarcastic comments.

    Pity, because I much prefer the Reddit interface. It’s far superior to Digg.

  80. 80.   Jack Says:

    Although I readily admit that I’m VERY unsophisticated about this stuff, I’d be willing to bet that much of what we’ve concluded in recent years will be proven wrong in the future as science “marches on.” I say this based on history which seems to indicate that a great deal of scientific consensus is proven wrong by future generations of scientists. Still, it’s pretty exciting to read about these “discoveries.” And who knows, maybe they’re right!!!

  81. 81.   Chat Marchet News Digest » The Universe is 13.73 +/- .12 billion years old! Says:

    [...] Find out more here… This entry was posted on Thursday, March 6th, 2008 at 10:06 am and is filed under le Chat Marchet. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. [...]

  82. 82.   Rager Says:

    What about sweet baby Jesus? The universe is 2008 years old +/- 34 years(the age of Christ). What is wrong with you people? Have you forgotten why we are here? It’s not to measure the temperature of the sky! It’s to live the best life possible to return to sweet baby Jesus. I’m not saying that beleiving in science is a one-way ticket to H-E-Double Hockeystick, I’m just saying remember what life is about!

  83. 83.   subcorpus Says:

    this exciting stuff …
    nice article … great info …
    so 12 billion years … not 6000 eh …?
    thats kewl …

  84. 84.   SpongeWorthy Says:

    Recombination is only a misnomer IF

    1) this was the first time the universe “expanded”. If it wasn’t, then this round was certainly a “re”combination.

    2) we fully understand the dynamics of the universe before the universe. How the matter existed in the moments/eons before the universe expanded isn’t clear to anyone so stating categorically that it’s a misnomer is highly debatable and not a position I’d want to be debating from.

  85. 85.   Seth Says:

    I believe in the “Big Bang Theory”, but have one question that anyone has yet to answer.

    If the universe expanded out from a single point of origin, what is the “space” called that the universe and big Bang occured in and what space does that space occupy and so on and so forth?

    Best Regards,

    ScienceGeek

  86. 86.   cyberson Says:

    No way, the bible doesn’t say it’s that old. If you don’t believe the bible, just consult the bible! It says right in there that it’s right.

  87. 87.   Paul Says:

    Please use the word “literally” correctly. Nothing is being nailed down literally. In fact, things are being nailed down figuratively!

  88. 88.   zeep Says:

    “We are the very first humans to be able to do this…”

    Really? I somehow doubt that, seriously.

  89. 89.   Carl Says:

    Theoretically…if the universe is flat and it is called infinite, then how can we believe it to be infinite when we assign it a rudimentary shape that takes form under a finite perspective? Imagine a sheet of paper under a microscope. When you see the fibers the space is larger and filled with gaps. On a small enough scale you could pass through the paper. If our universe is flat like the paper, from a far enough perspective you could see the whole. If the universe is defined by the clusters of matter that form individual galaxies, then the shape would mimic the elemental binding of particles like a drop of water on a flat surface. With each dying star more water is added to the drop.

    when we assign it a rudimentary shape that takes form under a finite perspective? Imagine a sheet of paper under a microscope. When you see the fibers the space is larger and filled with gaps. On a small enough scale you could pass through the paper. If our universe is flat like the paper, from a far enough perspective you could see the whole. If the universe is defined by the clusters of matter that form individual galaxies, then the shape would mimic the elemental binding of particles like a drop of water on a flat surface. With each dying star more water is added to the drop.

  90. 90.   Warren Says:

    This data assumes there was a big bang in the first place. Use the data outside of the big bang model and WOW holy crap batman, interesting revelations.

  91. 91.   Zed Says:

    DrewTerry, Er… why would it matter if someone was a “right-wing Christian fundamentalist”?

  92. 92.   Cusp Says:

    Sigh – Space is not a thing. Space does not expand – no matter what frame you look at it in. There is no physical manifestation of expanding space. It is a useful mathematical picture, but it is not physical.

    Expanding Space: the Root of all Evil?

    Francis, Matthew J.; Barnes, Luke A.; James, J. Berian; Lewis, Geraint F.

    Publications of the Astronomical Society of Australia, Volume 24, Issue 2, pp. 95-102. (PASA Homepage)

    Abstract
    While it remains the staple of virtually all cosmological teaching, the concept of expanding space in explaining the increasing separation of galaxies has recently come under fire as a dangerous idea whose application leads to the development of confusion and the establishment of misconceptions. In this paper we develop a notion of expanding space that is completely valid as a framework for the description of the evolution of the universe and whose application allows an intuitive understanding of the influence of universal expansion. We also demonstrate how arguments against the concept in general have failed thus far, as they imbue expanding space with physical properties not consistent with the expectations of general relativity.

  93. 93.   David Says:

    Question… if the universive was too dense and photons couldn’t pass through and microwave spectrum hadn’t yet “expanded” then what data are they reading prior to the expansion? Seems a little off to me…

  94. 94.   Corey Says:

    I think “recombination” is not a misnomer.

    The ultraviolet photons were knocking electrons off the protons as fast as they were combining. Each time an electron and proton combined, an ultraviolet photon was emitted, knocking an electron off some other proton.

    “Recombination” is a good term for the timeframe when things were sufficiently spread out that the electrons weren’t immediately knocked off again. This last gasp of photonic radiation is what we’re measuring. The last recombination started the modern period where neutral hydrogen existed for more than nanoseconds.

  95. 95.   josh Says:

    so if recombination was 375,938 years ago, is that the furthest back we can look, experimentally? is there something we can look at (other than photons/EM radiation) to peer back within the first few (hundred thousand) years?

  96. 96.   Celtic_Evolution Says:

    @ josh

    I think you misread… or maybe mis-spoke… recombination was not 375,938 years ago… it occurred 300,000 + years after the big bang.

  97. 97.   Ivan Says:

    @Tom Marking: what MartinM said. If you’re inside the flat 3-torus, it looks like a hall of mirrors, except without reflections. When you look straight ahead, you see your own back, and another copy of yourself in front on that one, etc. So there appears to be a whole 3D grid of copies of “you”, except there’s still really only one “you”.

    @BB: I understand better what you were getting at, now. However, “flat” does not imply “infinite”: the universe may be both flat and finite, just like the Asteroids universe or the 3-torus described above.

    I recommend Jeff Weeks’ flight simulator for the 3-torus and other flat/nonflat finite universes: http://www.geometrygames.org/CurvedSpaces/

  98. 98.   MartinM Says:

    This data assumes there was a big bang in the first place. Use the data outside of the big bang model and WOW holy crap batman, interesting revelations.

    Yes, it reveals that you ought to be using a big bang model.

  99. 99.   vincent Says:

    A very good article, i like it and i’m conscient to be lucky to know all theses facts, thank you !

  100. 100.   Tom Says:

    Space itself is not a nothing, it is ’spacetime’ which is a thing that can warp, ripple, and carry waves. This is part of relativity. Its actually (per mathematics) full of something called a Higgs field which gives things mass. Per quantum, the Higgs field is both waves and particles, or can be thought of as probability waves.

    Actually space can look both flat and be curved. It could be the outside of a baloon, or the inside of one, or it could be part of some other indeterminate shape so big that just our part of it looks flat. According to Expansion theorey (refined big bang math taking quantum into the calculations) the universe is at least so big and is expanding so fast that just the part of it that we can see is like rhode island on the surface of the globe. Everything else is beyond our event horizon. Although the globe is round, rhode island looks flat, becasue the globe which it is on is so large.

    These theoreys are tested which is the closest thing we can do to proving them by checking if #1 they can mathematically explain *everything* we see, and then #2 using the math to make predictions about things we havnt looked at yet and then looking and see if they matched up. If the math is so accurate it can predict reality that it is considered sound, as all math *is* is a description of reality.

    Quantum and Expansion theorey have been tested in this way multiple times and they have held up to be accurate prediction of reality. One of my favorites is how well they predict the irregularities in the distribution of the stars across the sky.

  101. 101.   Rory Says:

    I wish that they would provide the error bounds more often in the press. It is a very important part of experimental science and the concept isn’t too hard to grasp for a high school student.

    And on top of that it makes us scientists seem more . . . human. “Here look we know we aren’t exact, see we even worked out how inexact we are!”.

    (hmm I think of myself as a scientist, yay!)

  102. 102.   Thom Says:

    You said: “It was designed to map the Universe with exquisite precision, detecting microwaves coming from the most distant source there is: the cooling fireball of the Big Bang itself.”

    Wouldn’t the most distant point be PAST the point of the Big Bang to the other side of the expanding universe?

    P.S. Ow.

  103. 103.   TMB Says:

    josh: Gravitational waves, in principle, should be able to probe past recombination. Unfortunately, I don’t think we’ll ever detect any individual sources out that far, but there are predictions of the background fluctuations that we’d expect due to all of the sloshing around that happened in the early universe, and as an aggregate those might be detectable.

    Personally, I’m happy that the new value of sigma_8 (the overall amplitude of matter fluctuations on scales of 8 Mpc) is up to 0.8… the WMAP3 value was a little low compared to all other measurements, but 0.8 makes a lot of people happy.

    [TMB]

  104. 104.   The Earth isn’t flat, but the Universe is. « maxmorin.ca Says:

    [...] 72.1% is dark energy, 23.3% is dark matter, and 4.62% is normal matter.  Phil Plait over at the Bad Astronomy blog puts it best: “We occupy a razor thin slice of [...]

  105. 105.   David Says:

    It’s stuff like this – thinking about how much stuff is happening quadrillionths of a second after the big bang that really confuses me :S

  106. 106.   Cusp Says:

    > Space itself is not a nothing, it is ’spacetime’ which is a thing that can warp, ripple, and carry waves. This is part of relativity. Its actually (per mathematics) full of something called a Higgs field which gives things mass. Per quantum, the Higgs field is both waves and particles, or can be thought of as probability waves.

    Space is not a thing – and space-time is not a thing. I suggest you read the paper I pointed to.,

  107. 107.   Mathew Howell Says:

    G’day Science Geeks!

    Now before you take that to offence… I wish I was one, I wish I could understand more about astronomy and science and how it all works!

    I have a question for those who do understand: We know so much about the universe, minute details, temperatures, what colour something was when it was a few degrees colder 50 million years ago etc, what I want to know is… What is beyond the walls of the universe? What is the universe expanding into? Where is it going? Where does it end and what is beyond that?

    Cheers!

    Mathew in Asutralia

  108. 108.   Cusp Says:

    > What is beyond the walls of the universe? What is the universe expanding into? Where is it going? Where does it end and what is beyond that?

    There are no walls in the universe, so no beyond to worry about

    Cusp in Australia (wonder if its the same bit as Matthew)

  109. 109.   monSe Says:

    The total of percentage of dark matter, dark energy, and normal energy is 100.02%. So, my question is, why does the sum of all things equal more than what can be possible by the current laws of physics and mathematics?

  110. 110.   Mathew Howell Says:

    In the capital north of the monolith!

    Ok.. I understand the Universe is a complete different dimension, but how could i explain to my 7 year old (me inclusive) the answer to where does the universe end… and then he asks what is behind that, then what is behind that etc?

    Is there a physical example that makes understanding it easier?

    Cheers Cusp

  111. 111.   Mike J. Says:

    As a creationist… anytime I hear the terms “millions” and “billions” of years… It reminds me of another fairy tale I heard that begins with …

    ” a long time ago, in a galaxy far far away ”

    Basically when any “scientist” says such absurd things, and rounds off to the hundreds of millions (and then claims their numbers are accurate) you must be skeptical.

    I would like to ask *since its not on the study page, or on this one* what is the dating method they used… in other words… isn’t this whole dating thing based upon the obviously MADE UP and clearly flawed geologic column timetables?

    The interconnectedness of the branches of your socalled science will be its downfall… since you can prove the geologic column dating is totally wrong, then the dating that the astronomers use to calculate the age of the universe is ALSO totally wrong.

    HAHA

    rotflmao!

    Back to the darwin board boys!.. whoops I mean DRAWING board

  112. 112.   Cusp Says:

    We are along way apart – I’m in the place with the pretty bridge and opera house

    Given the current cosmological model – the universe is infinite in extent – it just goes on and on and on and on. This means if you head off, you can fly for an infinite amount of time and just keep going – no walls or boundaries, no outside.

    Although, funnily enough, you can’t explore an infinite amount of the universe in infinite time.

  113. 113.   Tire » Blog Archive » The Universe is 13.73 +/- .12 billion years old! Says:

    [...] from the WMAP probe have nailed down lots of cool stuff — literally — about the Universe.read more | digg [...]

  114. 114.   Mathew Howell Says:

    Well I hope you’re a Swans supporter… Thanks for your help!

  115. 115.   wangl0rd Says:

    This is all lies, see the Scientology timeline of the universe. We don’t need proof, just lies.

  116. 116.   allan Says:

    that’s nice..
    but what put me in awe here is how creative this article is made.. :D

    great post! more power!


    btw, does anyone know how long WMAP has been detecting these kind of things? you can’t just send a detector 10 minutes in open space and receive results already, so I was wondering how long was it reading these waves..

  117. 117.   Digital Says:

    I couldn’t focus on the article thanks to the ad-picture of the chick on the right.

  118. 118.   Ronn! Says:

    Phil started out his post with:

    “Happy birthday, Universe!

    Kinda. It’s not really the Universe’s birthday,”

    which reminded me of a story originally published in one of those science-fiction comic books back in the 50s or early 60s (which I came across some years later, probably sometime in the 80s). In the story, one day strange objects appeared on Earth, and as usual in such stories scientists were baffled. At the end it turned out that the objects were gifts from the other planets in the solar system because that day was the Earth’s four billionth birthday . . .

    (When the story was written you could still find mention of the hypothesis that the planets formed as the nebular disk around the Sun shrank, and periodically threw off a ring from the outside edge which condensed into a planet, hence the planets formed at different times, with Pluto — still considered a planet in those long-ago days ;) — therefore being the oldest planet and Mercury being the youngest . . .)

  119. 119.   SkepticTim Says:

    Cusp
    “Expanding Space: the Root of all Evil?” An excellent paper.

    However, from the experience of trying to explain the ‘big bang’ to a variety of students for the last forty years or so I still find it difficult to do so without resorting to mathematics that only a few understand. I keep looking for metaphors other than the balloon; which is misleading and always leads to the ‘Expanding into what?’ question. As but one more attempt, I offer the following; please tell me if it helps:

    Suppose there is an elastic band; a very long one. The band has very small dots on it; one dot for each and every integer that exists beginning with 1. So we have dots for 1,2,3,4,…. (keep counting for as long as time is!) … one dot for each count! The dots are very small and close together – touching even – but distinct. This situation is the universe (if you look in one particular direction) at the moment of the ‘big bang’. No matter how small you make the dots for each integer: How long is the elastic band?

    For some reason – (the reason is another story) – the elastic band begins to stretch (’the big bang’). Think what any one of the integers ’sees’ looking either in the direction of either the larger, or the smaller integers as the band stretches.

    Now suppose that, no matter what direction you look, you see another elastic band that is identical to the one above.

    If you consider any instant in time and you look about you in the universe of integer dots described above, you can use plane old Euclidean geometry for everything – the universe if ‘flat’. If you have to include time, then things are different – things aren’t where they where so the universe of space-time isn’t flat.

    Was this any less confusing???

  120. 120.   ron Says:

    Is there anything here that demands that the understanding of our ‘universe’ is truly a Universe, and not a local system amid a really True Universe? There are threads which speak of a universal existence of time and space, without beginning or end, within which such a universe as we exist in sparks into existence. I know, we are only aware of things that begin and end, so can’t reasonably grasp things that have no beginning or end. But, I’m asking, is our known universe reasonably known to be the only existance?

  121. 121.   Donde Says:

    WHERES YOUR GOD NOW?!

  122. 122.   Tom Marking Says:

    Another question I had was this. In the image the red spots are condensations of matter that will someday evolve into galaxies and the blue spots are voids where there is less matter, is that correct? Then can we pinpoint the red spot that will someday evolve into our Milky Way galaxy or our Local Group of galaxies or our part of the universe? Is that possible to do?

  123. 123.   Tom Marking Says:

    O.K. I’m getting more and more confused by the term “flat”. It was my prior understanding that in a flat or open universe if a traveller travels in a straight line (defined by a beam of light) then he or she will never come back to the same point. In a closed universe the traveller returns to the same point after travelling in a straight line. Clearly in the toroidal universe being described as “flat” a traveller travelling in a straight line returns to the same point. So there seems to be a different definition of what “flat” means in this case. I’m using the definition contained in this posting when I speak of a flat universe.

  124. 124.   Chris Says:

    I’m rather impressed, btw, at everyone’s ability to ignore the ‘trolls’ in the comments above and attempting to make things clearer to those who want to get it, but haven’t quite gotten it yet (like myself).

    You all show an incredible level of maturity.

    As for the article, for something science related, it was a fresh breath of fun to read. Good job.

  125. 125.   Donde Says:

    Tom, Its more like a disk, if that helps. Plus the outside link said 2% varitation. All gravity tends to form a disk shape over time, like our solar system, so this isnt anything new.

  126. 126.   shane Says:

    Mike J said : The interconnectedness of the branches of your socalled science will be its downfall…

    Totally agree. What has science done for us?
    The intertube.
    Ok, except for the intertube what has science done for us?
    Modern medicine.
    Except for the intertube and modern medicine what has science done for us?
    Industrialisation has allowed a good chunk of humanity to devote free time to art and sport and the pursuit of happiness instead of the daily drudge of attending to essential needs.
    Except for the intertube, modern medicine and industrialisation what has… ah fudge.

  127. 127.   HD Says:

    Quote: What they got was: the Universe is 72.1% dark energy, 23.3% dark matter, and 4.62% normal matter.

    Not really…

    WMAP mainly measures the difference between the incident microwave radiation from two foci. It does not measure dark energy or anything of the sort.

    When the WMAP data are used to constrain the parameters of the theoretical Lambda-CDM model of the universe, the given values are predicted with some level of confidence. Whether they turn out to be correct depends entirely upon the validity of the model.

    The putative dark energy is a derived quantity in the model. It has not been measured directly by WMAP or anything else. It is a numerical parameter that is necessary to make the model fit the observed data.

    Tossing off a value for the fraction of the universe that is dark energy without context is fanciful, to say the least.

    Mathematical models predict all sorts of things that might or might not be confirmed, such as gravitational waves and particular real values for the vacuum energy and so on. We should be aware that modeling is new and interesting, but not necessarily predictive.

    Science is the process of deriving generalizations from the iterative testing of hypotheses through experimentation. WMAP is not, strictly speaking, an experiment and Astronomy is not, strictly speaking, a science. To forget this is to make fools of ourselves.

  128. 128.   shane Says:

    Oops. Sorry Chris. Engaged keyboard before engaging brain.
    Otherwise this blog post and nearly all comments above have been really elucidating. Thanks.

  129. 129.   Ivan Says:

    @Tom Marking

    Flatness is a local property, not a global one. The question of whether space is curved on average (locally) is independent of the question of whether it has a finite or infinite global geometry. I really recommend the wikipedia article on the shape of the universe if you want more details.

    Apparently there’s also some potential confusion stemming from the fact that cosmologists use “open” and “closed” to describe the curvature, whereas mathematicians use those terms to talk about the global geometry.

  130. 130.   Andrew Says:

    If we’re at critical density now, how long have we been there, and how long before it begins some sort of Einsteinian curve and everything collapses?

    Could we use this data to predict the end of the universe just as accurately?

    Odds are, our galaxy will have merged with another by then and everything will be atomized anyway, but it would be nice to know in a Death Clock sort of way.

  131. 131.   David Says:

    I am scientific sceptic, only to the point where I the type of person who doesnt just read something and believe and argue for it without corroborating evidence/proof/research. That said, I have a couple of questions:

    What exactly do you mean in this point -

    1) The age of the Universe is 13.73 billion years, plus or minus 120 million years. Some people might say it doesn’t look a day over 6000 years. They’re wrong.

    Can you back up the ‘They’re wrong” bit? I understand creationists beleive the universe is only about 6000-10,000 years old, but scientific positions on this point out that many scientists are abandoning the Big Bang theory (yes, it is just a theory). And, if the universe was created, would it not be created “mature”? When a watchmaker creates a watch, he makes it so its all working from the start, not as an infant watch with half a band, a couple of gears and a small winder, in the hope that it will grow into a mature watch. This perhaps explains why there is the possibility of a universe which is physically mature but only 6000-10,000 actual years old.

    —————-

    My second question is where the rules for the Big Bang (if we consider it to have occurred) came from. Everything in the universe has a set of rules it follows, so the Big Bang must have had rules for it to have occurred yes? I mean, something had to have been there to bang, and those things must have banged for a reason…stuff doesnt just bang without a cause. So who or what made the rules the Big Bang had to follow?

  132. 132.   L’âge de l’Univers - sur Whitedwarfs.org (La science, c’est aussi de la culture) Says:

    [...] The Universe is 13.73 +/- .12 billion years old! [...]

  133. 133.   Science Etcetera Venusday, 20080307 « ideonexus Says:

    [...] to the Wilkinson Microwave Anisotropy Prob (WMAP), we now know, the universe is Flat (within a 2% margin of error) and 13.73 Billion Years old (+/-120 million years). How can something be “flat” within a two-percent margin of [...]

  134. 134.   Shane Says:

    David, assuming you’re not trolling and you genuinely interested you may not be aware you’re propagating a couple old canards, and I don’t mean ducks, that might make a few around here suspicious that you’re a troll. Specifically the watch thing, the it’s just a theory thing and the first cause thing.

    So maybe you could clarify a couple of thing first.
    1. Can you provide evidence that many scientists are abandoning the Big Bang theory?
    2. Can you define theory?
    3. Who is maker of the rules?
    4. Who/what made the maker of the rules?

  135. 135.   Josh Says:

    Of course you realize this is only an estimate of how long it has been since the big bang, and not the age of the existing matter of the universe, there’s nothing to say there was no universe before the big bang. Should have been made with a proper title.

  136. 136.   Josh Says:

    In response to david, if he believes in creationism of any sort then things to bang all the time without reason.

  137. 137.   David Says:

    Not trolling at all. They are genuine questions. I read an article in New Scientist about the scientists questioning the validity of the Big Bang and trying to find another more plausible explanation. I cant remember the issue number or I would provide it. So perhaps we disregard that statement.

    A theory is a set of ideas/hypotheses which attempt to explain something. Why did you need a definition for this?

    My very question was, although perhaps hidden in the statement, exactly what you have asked Shane; “Who[/what] is the maker of the rules?” They cant have just existed…nothing ‘just existed’…at least, it doesnt makes sense to me that stuff could just exist.

    The last question is one of perpetual mystery…who created the rules, who created that entity, and who created them and so on…it could go on forever. So for the sake of simplicity, lets keep it at one entity creating the rules…if that is indeed what happened. Or is the universe simply one of the marbles in the pocket of a being – as it was so portrayed in ‘Men In Black’

  138. 138.   Orjeej Says:

    I am a layman and not very well acquainted with the upper levels of astronomy and physics, but what I have learned so far from this discussion is the universe is infinite with a finite amount of matter, it is shaped like a disc sort of like a cd without the hole, and no matter how fast you go in a straight line you will never reach the edge. Things that are still confusing and seem rather pesky are whether space is expanding which I take to mean something like the volume of space inside the universe is expanding or whether space is not a thing and can’t expand.

    Anyways this was an excellent article that makes me feel awed by what science has the possibility to show to us with a reasonable margin of error. I love it when reason and sense help humanity grow and change in such interesting ways.

  139. 139.   MartinM Says:

    Then can we pinpoint the red spot that will someday evolve into our Milky Way galaxy or our Local Group of galaxies or our part of the universe? Is that possible to do?

    No. The CMBR originates at every point in space, but anything local is long since gone; what we observe is coming from a great distance.

    Imagine you’re standing in the middle of a pond in a hail-storm. When the hail stops, all that’s left is circular ripples from the last impacts, expanding outwards from every point in the water. The ripples from impacts nearest you will pass your position early, never to be seen again. As time passes, ripples from further and further away will reach you. If all ripples are travelling at the same speed, at any given time the ripples arriving at your location originated on a circle centered on you.

    The CMB is like this; it permeates the Universe, travelling in all directions. But we can only see those CMB photons which originated on a spherical shell centered on our location.

    It was my prior understanding that in a flat or open universe if a traveller travels in a straight line (defined by a beam of light) then he or she will never come back to the same point.

    No, you’re conflating two separate concepts, curvature and topology. The simplest cosmological models all have trivial topology – they are simply connected. A flat, simply connected manifold has the property you describe. The torus is a flat, multiply connected manifold.

  140. 140.   MartinM Says:

    Whether they turn out to be correct depends entirely upon the validity of the model.

    That’s true of everything. You can’t tell me what colour your socks are without assuming the validity of some model or other.

  141. 141.   MartinM Says:

    And, if the universe was created, would it not be created “mature”?

    There’s a difference between appearance of age and appearance of history. A watchmaker would certainly make a complete product, but he wouldn’t crack the face, tarnish the metal, and fray the strap to make the watch appear older than it really is, unless he wanted to deceive us.

    Similarly, a creator might want to make a Universe complete with stars and galaxies, but if this Universe is that Universe, then what are we to make of distant supernova? Apparently, the creator saw fit to create streams of light carrying images of stars which never existed in the first place. This isn’t maturity, it’s history. Same for the Earth; a mature planet doesn’t need a history showing billions of years of continental drift, for example.

    Of course, it’s always possible that a vastly powerful being is trying to deceive us as to the true nature of the Universe, but that’s hardly a useful hypothesis.

    And the reason you were asked to define ‘theory’ is because you pulled out the ‘just a theory’ canard. You seem to be under the impression that theories are uncertain, shaky models which could be thrown out tomorrow. On the contrary, theory is the pinnacle of scientific method. We have atomic theory, germ theory, the special and general theories of relativity, quantum theory, the theory of evolution. In none of these does ‘theory’ denote uncertainty. Everything on that list is as close to certainty as science can ever come. These are some of the greatest achievements of science.

    Everything in the universe has a set of rules it follows

    No. The map is not the territory. Everything in the Universe can be described by a set of rules. There’s a difference.

    So for the sake of simplicity, lets keep it at one entity creating the rules

    Why is one simpler than none? Do rules always need rule-makers?

  142. 142.   MartinM Says:

    They cant have just existed…nothing ‘just existed’…at least, it doesnt makes sense to me that stuff could just exist.

    Oops, missed that one. If stuff can’t ‘just exist,’ then where does that leave us? If the Universe doesn’t ‘just exist,’ and the creator doesn’t ‘just exist,’ then we’re stuck with either an infinite regress or a causal loop. In either case, the creator doesn’t seem to add anything.

  143. 143.   MartinM Says:

    but what I have learned so far from this discussion is the universe is infinite with a finite amount of matter

    No. The finite speed of light allows us to see only a finite section of the Universe, which contains a finite amount of matter. The simplest models consistent with observation are spatially infinite, and contain an infinite amount of matter, evenly spread (to a reasonable approximation) throughout.

  144. 144.   Devo the MAD Says:

    Sayeth the BA :

    “We occupy a razor thin slice of reality.”

    Reality – whats that? ;-)

    Some would say 5 % is about my grip on sanity too! ;-)

  145. 145.   Devo the MAD Says:

    Not me though! Naturally! 8)

  146. 146.   Devo the MAD Says:

    Of course, what;s relauty does depend on how much you’ve drunk …

    How Coopers pales is that now … ? ;-)

    *!@!!@!!##@!##!@ cosmology! Give me stellar stellar astrosphysics anyday! That I can get my head around ..almost .. ! ;-)

  147. 147.   Mentionable Says:

    “How Coopers pales is that now … ? ”

    Shouldn’t that be :

    “How *many* Coopers pales is that now … ? ” [Best beer in Oz!]

    I’m guessing it should be! & I’m guessing quite a few! ;-)

  148. 148.   Devo the MAD Says:

    “# Mentionableon 07 Mar 2008 at 4:33 am
    “How Coopers pales is that now … ? ”

    Shouldn’t that be :

    “How *many* Coopers pales is that now … ? ” [Best beer in Oz!]

    I’m guessing it should be! & I’m guessing quite a few!”

    Darn right! ;-)

  149. 149.   andante Says:

    Who wants to take a bet?

    How long will it be before the creationist horde co-opts this new data by saying that 95.3% of the universe must be god?

  150. 150.   David Says:

    MartinM, as much as I would like to continue this conversation, I dont want to detract from the original subject and begin a dialogue that can go on in differences of opinion for as long as the universe is old, but i am happy to continue discussion via email if you would like to do so. (Anyone else is welcome to this invitation)

  151. 151.   Jay-D Says:

    The Universe is flat? Yeah, that’s what they said about earth. I’m not buying that one again…

  152. 152.   Nate Says:

    …at least, until the whole of the expanding universe burns out into cold, energy-less darkness and entropy in another 20 or so billion years.

  153. 153.   Shane Says:

    I, for one, welcome our new dark overlords.

    Now we know his noodley appendages are dark. Dark from the vast amounts of celestial squid ink required to turn his pastafarian visage black.

  154. 154.   Shane Says:

    I’m loving this thread. My favourite footy team gets a mention (the Swans) and now a gratuitous mention of one of the better ales available (Coopers).

  155. 155.   Cosmology News « Twisted One 151’s Weblog Says:

    [...] baryonic matter, 23.3% dark matter, 72.1% dark energy) of the universe. You can read more here, here, and [...]

  156. 156.   DUd3 No 3 Says:

    well written article and also a nice deconstruction of why corporate christianity is essentially without meaning in todays world.

    So, at some point in the past hydrogen couldn’t form. Protons couldn’t pass light, and the universe was opaque, Then it cooled down to a certain level which allowed another reaction to occur….Has anyone put any thought into whether this kind of event could occur again? whats next?

  157. 157.   TheTick Says:

    An uninformed question (I’m sure I don’t understand the methodology):

    Spoken in rough terms (i.e., wiggle around what I’m saying here), if we are able to look in one direction and use the light to determine the age, and look in the other and get the same answer, yet we are NOT in the center of the universe, then what does someone at the extremes of our vision see? Since they too are not in the center, shouldn’t they see basically the same distances as us? Knowing these things how can we know the size in any reliable manner?

  158. 158.   ha ha Says:

    jesus isn’t going to be happy…

  159. 159.   Fand Says:

    I like this entry since it gets info out to the public. However, people should know that physicists have known this for quite some time. There have been estimations at around 13 billion years for a few decades now.

    People need to understand that we don’t know what dark matter is made of and it’s not entirely proven really. It’s just our best explanation for the gravity of the university. The theory of Dark Matter is beautifully purposed with strong mathematics and has the highest chance of being correct, but theories in physics get tweaked all the time and sometimes even proven incorrect. The public just latches on to the theory since it boggles the human mind. Similar to string theory, which is way out there and has many loop holes that we may never even be able to test.

  160. 160.   Shane Says:

    MartinM, if we can “see” to the edge of the universe would that not mean that the universe is finite and that means the matter contained would be finite? I suppose it is something like the question The Tick is asking about whether or not we’re only seeing to our… ability to see?

    Was the speed of light different for a period shortly after the big bang or was there something that could be called the speed of light anyway (could it be measured)?

    I think I am missing the point somewhere? The universe is seriously weird (in a fantastic it’s great to be alive way).

    BTW, excellent response to David.

  161. 161.   The Universe is 13.73 +/- .12 billion years old! « Gilliam Family Blog Says:

    [...] The Universe is 13.73 +/- .12 billion years old! [...]

  162. 162.   The Open Conspiracy » Blog Archive » » The Earth is not flat the universe is Says:

    [...] bad astronomy website has some good info on a NASA study that gave a lot of information on how the universe [...]

  163. 163.   Matt Says:

    Appears as though you have been Slashdotted as of a couple minutes ago.

  164. 164.   Newton Says:

    It has also been theorized that Dark Matter only exists as a mathematical error.

    Just as Newtonian physics doesn’t apply at the subatomic scale, Newtonian physics may break down at the mega scale. If I remember correctly one scientist once showed that by adding a coefficient (or maybe it was multiple coefficients) or by adjusting Newtons formulas slightly the mathematics comes back in line.

    Wish I could actually remember more about that.

  165. 165.   Tom Marking Says:

    “No, you’re conflating two separate concepts, curvature and topology. The simplest cosmological models all have trivial topology – they are simply connected. A flat, simply connected manifold has the property you describe. The torus is a flat, multiply connected manifold.”

    O.K. Then let me ask another question. Was there anything in the WMAP results which indicated what type of manifold the universe is? And can the theory of general relativity handle anything other than a simply connected manifold?

  166. 166.   kris Says:

    I knew Scientologists were wrong about the age of the universe. Those tricksters.

  167. 167.   How many candles is that??? « life in the minivan lane Says:

    [...] some other news in aging. NASA’s WMAP has been examining the universe, and thanks to Bad Astronomy putting things in plain old English, we now know (or as much as we can know these things) that the [...]

  168. 168.   JoeAverage Says:

    I simply cannot visualise any of this. Is it just me or do the math guys have some special visualisation skills or perceptions that I don’t?
    Also, what if we were to accept dead straight that we, humans _cannot_ visualise more than 3 dimensions?
    Then, we could simply say – “it can’t be visualised, don’t try it, your head will hurt, so be content with the visualisation of the 2D analogy which is so-and-so”
    Then, having excused ourselves from the torment of visualising warps and surfaces, we coudl simply say: This space-time thing it’s an object like a 3D object after all just subtract one dimension from all examples and you’ll get decent 2D visualisations. 3D ones are not possible with human brains.
    Then, there would be time that could be plotted on a fourth axis. And a 4D space would be the actual structure of this thing called universe.
    And the changes in that structure actully happen in a 5th dimension called “Time++” or t1 or t’ or something.
    So, in the beginning of t’, when t’=0, the bigbang happened.
    The universe is lodged as a ball/sphere/flatsheet/whatever in a 5D space (4d-and-t’) and when seen in that t’-enabled world, we find that the universe measures exactly 13.73 bn units of t (normal time)
    And finally that the sense of time passing is actually our *entire* universe sliding along on the t’ axis.

    Does this make any sense? (I think not, of course)
    TIA!

  169. 169.   Johnsenclan » Blog Archive » links 3/7/08 Says:

    [...] Universe is around 13.73 billion years [...]

  170. 170.   Depleted Cranium » Blog Archive » The age of the universe now known better than ever! Says:

    [...] This comes from our friend Phil Plait over at Bad Astronomy. The WAMP (Wilkinson Microwave Anisotropy Probe) was launched by NASA in 2001 in order to take the most precise measurements to date of the variations in the microwave radiation of the universe. This omnipresent microwave energy is actually an expression of the energy from the big bang itself and has been resonating ever since the birth of the universe. The WAMP has been cited numerous times before for providing cosmology with some of the best data avaliable on the origins and nature of the universe. [...]

  171. 171.   Mike Says:

    What does “three minutes” mean during the first 3 minutes of the universe, given the relativistic nature of time?

    The Universe is “expanding” at maximum “speed”, right?

    So objects at one “edge” are moving outward at 186,000 miles/sec, and at the opposite edge they are moving outward at 186,000 miles/sec…

    If someone is moving away from me at the speed of light, they appear to be standing still… right? And I appear to be standing still too, to them, right?

    So my local clock is ticking… but their distant clock appears to have stopped.

    But where is the clock positioned, relativistically speaking, that (assuming a clock could exist in the primordial soup, which is of course absurd in itself) that measures the passage of 3 minutes?

    Or in other terms, does time have any meaning or the same meaning at the beginning of the universe that it does now?

    I’m asking this in the context of general relativity theory… of course it is possible that whole other dimensions of space and time come into play that we have no conception of at that density of matter and energy… but just in terms of conventional relativity theory, I’m asking the question of whether there is any position from which to measure the passage of time…

    Sorry if this is a “dumb” question… God knows there really are some dumb questions out there… don’t let anyone tell you otherwise.

  172. 172.   The_Shoe Says:

    Where did all of the energy that made the big bang so hot come from?
    And wouldn’t whatever was around that induced the big bang, be our early universe? How old is that?

  173. 173.   Cusp Says:

    > The Universe is “expanding” at maximum “speed”, right?
    So objects at one “edge” are moving outward at 186,000 miles/sec, and at the opposite edge they are moving outward at 186,000 miles/sec…

    The universe is not a grenade explosion into preexisting space – there is no “edge” other than the hubble sphere (which is not a physical thing) – its just the amount of universe we can see (the visible universe).

    Given the current cosmological model -
    The universe is infinite – it was infinite at the big bang, it is infinite now. It contains an infinite amount of mass. We can see a finite piece of this.

  174. 174.   drew terry Says:

    [quote from story link] http://map.gsfc.nasa.gov/universe/uni_shape.html
    GEOMETRY OF THE UNIVERSE
    “The density of the universe also determines its geometry. If the density of the universe exceeds the critical density, then the geometry of space is closed and positively curved like the surface of a sphere. This implies that initially parallel photon paths converge slowly, eventually cross, and return back to their starting point (if the universe lasts long enough). If the density of the universe is less than the critical density, then the geometry of space is open, negatively curved like the surface of a saddle. If the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper. Thus, there is a direct link between the geometry of the universe and its fate.

    The simplest version of the inflationary theory, an extension of the Big Bang theory, predicts that the density of the universe is very close to the critical density, and that the geometry of the universe is flat, like a sheet of paper. That is the result confirmed by the WMAP science.”[end quote]

    If whichever way we look out in space to “look back in time” then what is looking way in the opposite direction?

    Even and especially if we accept the assumption that “space is flat” there has got to be a direction to flat space.

    If we look in the opposite of the direction we look in flat space to “look back in time” to “look forward in time” in flat space.

    Alternatively stated: if every direction we look in space “looks back in time” then how is that looking back in time?

    That puts the Sun (light) at the center of time emerging from Earth (matter) in heliocentric orbital lunar rotation (angular momentum of matter in motion).

    What is time?

    What is “looking back in time?”

  175. 175.   Mike Says:

    Cusp… of course… I knew that (ha!). Thanks for the reminder.

    I still don’t get whether time has meaning or the same meaning in a super dense rapidly expanding space time kerfluxel.

  176. 176.   Cusp Says:

    > What is “looking back in time?”

    It has taken time for light to get here from out there – hence we see there as it was when the light set out.

    We look back in time.

    Take a look at figure 1 in the below paper.

    http://arxiv.org/abs/astro-ph/0310808

  177. 177.   Jay Gaulard Blog » Blog Archive » Daylight Savings, Marathons, Solar Film and the Universe Says:

    [...] The Universe is 13.73 +/- .12 billion years old! [...]

  178. 178.   Memophage Says:

    Holy … I just got a big jolt of perspective. The earth (and our sun) is currently accepted to be about 4.5 billion years old.

    So according to these results, the entire universe and everything in it is only about 3 times older than the earth itself. I’d heard somewhere that our sun was posited to be a 3rd-generation star, but that hadn’t really clicked in.

    Given the number of galaxies we can see out there, that seems like a heck of a lot of stuff to come into existence in just three earth-lifetimes. Just sort of puts things into perspective… if heavier elements from a 3rd-generation star are required for life to form on a planet (pure conjecture on my part), then we could well be the first “intelligent” species to arise in the universe.

    Given the sheer number of stars out there this is rather unlikely, but we should be among the first at least, speaking universe time (+/- a billion years or so).

  179. 179.   joe Says:

    The astronomy culture is one of the worst for stating theories
    as fact and firmly tying observational data to that theory when the connection is not known to be 100% confirmed. Big Bang is still a theory for many good reasons. Until it’s proved or disproved, I wish
    it was the LAW (lol) that items such as this include the word ‘theoretical’ as in the theoretical age of the universe. There is the possibility that ALL this turns out to be false. If it is false it really doenst help to be talking about it like it’s true because that will DEFEINATELY hinder progress towards the actual facts. Im not saying
    BB isnt true, Im saying its very important to remember it isnt known
    to be true.

  180. 180.   joe Says:

    The deeper in to a gravity well you go, the slower time runs. Not only do planets have gravity wells, so do galaxies and galactic neighborhoods. On the other hand, there are voids in the universe that are HUGE: Most matter is actually concentrated in filaments and walls of vast empty areas. The centers of these voids are closer to 18 billion years old. I’m still having a hard time imagining what happens to a photon that traverses this region, including just how far does it travel and how big IS that space. Still, your title and summary don’t even hint that the people analyzing the WMAP data have corrected for this distorting effect. They may even be unaware of it.
    I guess what I’m saying is that your title should be more like “The Universe is 13.73 billion years old, around here at least.” :-)

  181. 181.   Snarky Bastards » Blog Archive » Shhh! Don’t Tell the Fundies Says:

    [...] Don’t Tell the Fundies Science provides a fascinating look into the early history of our [...]

  182. 182.   Chris C. Says:

    I’m the one who submitted the story to /. that was eventually put on their front page. Which is nice because that almost never happens to me, but I’m deeply disappointed that they changed my headline: “The World is Flat”.

  183. 183.   joe Says:

    like for example :
    http://www.physorg.com/news77190620.html

    “In their paper, he and his co-authors demonstrate this using data from 15 well-studied galaxies. Among this data was each galaxy’s “rotation curve,” a graph that plots the rotational speed of the stars in the galaxy as a function of their distance from the galaxy’s center. These curves were successfully fit to curves produced using the new theory. Since these 15 galaxies are believed to be dominated by dark matter, fitting their rotation curves using this new gravity model is strong evidence to support an alternative theory of gravity.

    Despite this, the notion that dark matter and dark energy are “wrong” is potentially very unpopular. Capozziello and his colleagues are aware that a new theory of gravity impacts the dynamics of the universe as scientists now understand them. “…..

  184. 184.   Rob Says:

    its funny to speak with creationists about this topic. they have a very limited number of things to rely on, but ultimately they rely on faith to back up their science. what do you think the best way to shut down a creationist would be (aka. one of those guys who say the universe is 6000 years old)?

  185. 185.   Cusp Says:

    >The astronomy culture is one of the worst for stating theories
    as fact and firmly tying observational data to that theory when the connection is not known to be 100% confirmed. Big Bang is still a theory for many good reasons. Until it’s proved or disproved, I wish
    it was the LAW (lol) that items such as this include the word ‘theoretical’ as in the theoretical age of the universe. There is the possibility that ALL this turns out to be false. If it is false it really doenst help to be talking about it like it’s true because that will DEFEINATELY hinder progress towards the actual facts. Im not saying

    Have you actually read a scientific paper? Nothing is ever proved, not Newton’s Laws, not quantum mechanics, not thermodyanmics nothing.
    Please try and understand science.

    Reading science in the media is not a true reflection of scientific results.

    As I have written many times here and elsewhere, “if GR cosmology is right and the measured parameters are correct then…”

    All scientists know that it all comes with the caveat that it all may be wrong. It does not hinder progress to continue along the same road because eventually it will be seen to be wrong, and that would mean there is more to do.

    The biggest hinderence to science is people who don’t understand what science is and what it does.

  186. 186.   Christopher Says:

    There is a little problem with this number…. it doesn’t take into account the possibility, if not probability, that the universe could have had more than one Big Bang.

    The universe could be INFINITELY more ancient than this number, but we do not know because the sequential Big Bangs have wiped out any evidence of the former Big Bangs.

  187. 187.   Orjeej Says:

    So this might seem like a strange question but how is infinite used in conjunction with astronomy. Is infinite used differently in terms of space i.e. infinite space refers to a always expanding universe where it is impossible to reach the edge, then what does infinite matter refer to is matter created constantly and is appearing at some position in the universe? If matter is constantly being created then shouldn’t energy be created constantly as well?

    Sorry for the silly question.

  188. 188.   Curelom Says:

    > Creationist – There are some assumptions made on the blog here stating that ALL creationists/christians, etc. believe that the universe, or even the earth is aprox 6,000 years old. This is not correct. While there are many who do believe this, there are christians who believe that the earth and universe may be older and that the creation ocurring in 6 days was a figurative reference to 6 periods of time. Nor do all creationist believe that the earth was the first creation and that the words in the beginning refer to the beginning of the earth, rather than the beginning of everything. So the age of the Universe does not prove the existance or non-existance of God.

    > in/finite matter/space – It seems to me that to travel in an infinite universe forever and never come across anything as unlikely. If there was a big bang here, who’s to say there wasn’t another big bang someplace else and that our universe is one of many universes. I’m not talking parallel universes, but different universes in different places of space.

  189. 189.   Eric Says:

    what a complete load of crap…. that article just killed a few of my brain cells.

  190. 190.   jeffmcfadden.com » Ye Olde Universe Says:

    [...] if the universe isn’t really 13.73 billion years old, then why does it look that [...]

  191. 191.   Brian Says:

    Great post, Phil.

  192. 192.   Paul Basken Says:

    Cool. So what was going on 14 billion years ago?

  193. 193.   Browncoat Jedi Says:

    You know, the interesting thing is that the Bible doesn’t say that the Earth is 6,000 years old.

    In fact, the majority of Jews – from whom the scripture came – do not believe it is 6,000 years old.

    Nor do the 2 billion Catholics in the world.

    Nor do the nearly 1 billion (maybe more) Muslims in the world.

    Yet they all believe in the books of Moses.

    The belief that the Earth was formed in 4,004 B.C. is held only by a small, minority sect of protestants who insist on interpreting the Bible literally. Problem is, that a literal interpretation of the Bible doesn’t support this theory – there are gaps in the genealogies which make arriving at an exact date impossible. In fact, you can’t even get a ballpark figure using literal interpretation, because the books weren’t written as an historical or scientific reference. So things get left out that you would need to know to determine even the approximate dates.

    Suppose, for an instant, that you are God, telling Moses how you created the world:
    God: In one femtosecond, I created all the matter in the Universe.
    Moses: What’s a femto-second? How many days is that?
    God: It’s a, wait, oh, nevermind… Let me rephrase that: I spoke and created the Universe on the first day…

    It’s not false, but it’s not precise either. However, it is as precise as could be written down at the time, because the concept of a femto-second wouldn’t become widely known for another 40 centuries.

    No matter what the topic, you can find people who will read their particular biases into anything. You can find the same behavior among the Da Vinci code believers who think somehow that, in spite of the book being fiction, the Catholic Church is “hiding the real truth”. Kind of like the 9/11 and JFK conspiracy theorists.

    I’m not sure why people like to trot out the 6,000 year old theory every time someone mentions the age of the Universe. Perhaps it is because they’re seeking an opportunity to tar the faiths of the world

  194. 194.   Bob Says:

    Was that 13.73 billion years (+/- 120 million) from today or from January 1?

    Excellent article!

  195. 195.   joe Says:

    “All scientists know that it all comes with the caveat that it all may be wrong. It does not hinder progress to continue along the same road because eventually it will be seen to be wrong, and that would mean there is more to do.”

    This is kinda assumed as scientists are assumed to be intelligent.
    But in direct response to that I would say it (theory preference) does hinder progress in that it diverts thought and resources to the theory at the expense of alternate theories. So it actually literally does hinder progress. The ONLY way it would not hinder progress, is IF an attempt was made to guide the process itself by scientific method. It may sound like that must be intrinsic, but the culture of the science community is just that, a culture like any other that happens to be made of scientists. You cant control, test, observe etc the community the way you can experiements. But it seems (you probably know more that I about this) that the Ast. community suffers greatly from a ‘true until proven false’ syndrome once a theory takes hold. The dangers of this I and others feel compelled to constantly voice. One of the most significant aspects of this disfunction is the way
    that the ‘fashionable theory’ of the decade or century gets most of the FUNDING, press, etc. The theory infests and sustains itself, for better or for worse, influencing all ages. Yeah I get it. But the community as a whole, (not its parts or their sum), does NOT get it.
    Our culture is often so sensitive to politically incorrect verbage. We need to be more sensitive to scientifically incorrect wording, not just
    in some circles occasionally.

  196. 196.   Jon T Says:

    I have always had an intense interest in astronomy, and cosmology. As always, we discover more and more each day. Still there will always be things that are unknowable. As it states, we are a thin slice of reality. I recently watched a show about Stephen Hawking, and the fact that he now admits being wrong about data being destroyed by black holes. I think even the world’s top astrophysicists don’t understand singularities any better than some average astronomers. I suspect there is no way to actually know what happens in black holes, and just maybe they are doorways to countless other universes.

  197. 197.   Jon T Says:

    Another thought…. The Universe is a fairly big place, maybe we don’t really have a clue how big it is, and maybe our known universe is just one of billions…. Sort of one giant redwood in a forest of redwoods. It seems more likely that the universes have always been here, and always will be…. It’s just that our universe is a recently started subdivision in the neighborhood only some 13.73 billion years years ago. Might be that our known universe is really very young on a scale of time that covers unlimited other dimensions.

  198. 198.   Results from WMAP: The Universe is 13.73 +/- 0.12 Billion Years Old Says:

    [...] leading to the conclusion in the headline.  Phil Plait, the “bad astornomer,” has a nice summary posted for your edification and [...]

  199. 199.   Normal Matter < 5% of Universe « A blog on math Says:

    [...] to be discovered in physics and astronomy is the properties of dark matter (exactly what is it?).  Bad astronomy has a post with a summary of the results from WMAP. And the biggest surprise for me was that normal [...]

  200. 200.   james Says:

    The universe isn’t expanding. It just looks that way because everything in the universe is shrinking!

  201. 201.   El Tamiz : Resultados de la misión WMAP Says:

    [...] Bad Astronomy Blog. [...]

  202. 202.   Nargun Says:

    Reading some of these replies has taken a few major decimal points off my IQ … phew ….

    Energy is an intrinsic part of the vacuum, and manifests itself in particle-antiparticle pairs. The Big Bang axiom is that space-time as it was then, had an immeasurably high energy potential; it crossed a threshold and began to lessen. The energy for the Big Bang came out of space-time itself “unravelling”. From this we get the various “types” of energy separating, the “types” of energy being gravitational, electro-weak, electro-strong, magnetic – before the Big Bang they were bound together.

    The “expansion of the Universe” could just as well be termed the “lessening of the vacuum energy potential”, if I actually understand the theory correctly. As the space between the frozen energy – matter by another name – “expanded”, the energy of the vacuum lessened. (I’m aware of the argument that the Universe is “infinite”, but if that was true, then the “steady state” theory of the Universe would simultaneously be true, and I can’t get my head around _that_ contradiction.)

    Just my 0.02c

  203. 203.   KD Says:

    @joe:

    As cusp said, all working scientists understand that the prevailing theory on a topic is just the best explanation we have so far devised. But to make progress, when you have a theory that has proven pretty successful, it is a good bet that you will make more progress by focusing work on projects aligned with that theory rather than running off in many directions at once.

    Note that often a project’s purpose is to test a prediction of a theory. If such a project turns up a result inconsistent with the theory, that builds interest in more investigation to see why it was inconsistent. Sometimes the experiment is bad or improperly run; sometimes the theory doesn’t accurately describe nature.

    When a theory has been found not to accurately describe nature, there is more interest in funding work that is directly aimed at developing other theories, or at least modifications of the current theory, since there is clear evidence that something is wrong. But that isn’t the only time work gets done on competing theories. There is always some activity going on toward devising competing theories. Occasionally such work gets mentioned in the nonscience press, but not very often precisely because it isn’t in the mainstream and the nonscience press has a hard enough time keeping mainstream science straight.

    I’ve read occasional articles and books that mention individual scientists or certain areas of investigation finding it impossible to get funding. I can’t give any first-hand evidence on that kind of thing, but I have a feeling that, while it might happen a little, it isn’t a large problem. Most of those reports probably are a result of people who lose out in the competition for funding feeling that they have lost for reasons they are imagining, not simply that there wasn’t enough money to fund everyone.

    The point you raise about articles assuming theories as fact is mostly a failing of the nonscience press. If you see anything like that in scientific writing, it is just a shorthand, and the audience mentally fills in the missing bits. I’m not sure whether the writers in the nonscience press actually understand the situation and simplify their articles because they think their readers don’t have the patience or intelligence to read an accurate report, or the writers just don’t understand it themselves. Whichever it is, I’d claim that it is a failure of general education: too many people don’t understand the scientific method. The scientists, I assure you, do understand it.

  204. 204.   There’s a lot of candles on that birthday cake « Call me Brandon Says:

    [...] Wow, Bad Astronomy is reporting that NASA recently measured the age of the universe to be 13.73 billion years (plus or minus 120 million years, but who’s [...]

  205. 205.   joe Says:

    re: theory preference: I dont have the memory to recall specific examples of ‘theory preference’ wasting time and money big time, not to mention greatly hindering the career and reps of disenters. But I think there are some if you look at all areas of science, medicine, etc.
    Anyone? It would be an interesting list. One small one I can think of is ulcer research. 1982 Australian physicians Robin Warren and Barry Marshall first identify the link between Helicobacter pylori (H. pylori) and ulcers, concluding that the bacterium, not stress or diet, causes ulcers. The medical community is slow to accept their findings.
    I fully understand the great posts such as KDs. But I still assert there can be a potentially harmful myopia due to the popularity of the ‘best fit’ of the day. A mostly unrelated example: How about how nobody bothered testing the Hubble before launch? It may sound arrogant of me but there’s no way I would have let it go without thorough ground testing. (yes flaw would have shown up that way). There are indeed some very good reasons to doubt DM, (even BB, the redshift/background noise interpretation).
    Here’s someone who kinda feels like me http://dharma-haven.org/science/myth-of-scientific-method.htm From the “WHAT’S WRONG WITH THIS PICTURE? ” section:
    “In an immature scientific discipline, the prevailing lack of understanding of the domain of interest makes coming up with a good theory difficult, if not impossible. A good theory helps, but a bad theory, prematurely scraped together in the mistaken belief that a theory is required before scientific work can proceed, can stifle interesting scientific work. ” Its better to read the rest also. Its not exactly the same thing Im talking about, but it comes from the same place mentally. Our entire current cosmology is built on using BB, (the redshift/background noise interpretation). But none of those (to my limited knowledge) have been observationally proven to a degree of confidence that warrants their widespread use and popularity. For example, show me where redshift derived assumed velocity is consistently proved by angular observations (or something as reliable). Astronomy requires so much inference, that we are BETTING our ENITIRE science on our current inferences. Seems we should be a bit more concerned those are accurate!! We hear all the glamorous work like on the age of the universe etc based on the pref theory. But we never hear about events that actually increase the confidence of that theory. Elucidating redshift, I say, might be more relevant work. I wonder if current theories are any more valid now than when they were first offered. What more has been found to show that background noise is from BB? What besides redshift backs it up? How do we know with reasonable certainty that redshift isnt at least affected by something other than velocity? What’s disconcerting is that there is no such thing as an organized, funded effort to research such basic things. That just isnt how the ‘culture’ of it all works, EVEN if it turns out to the most important of all. Redshift especially is SO fundamental. It’s our proverbial yardstick. It seems we should be more concerned with its reliability. Shouldn’t we?

  206. 206.   Tom Marking Says:

    There may be a fly in the ointment and that is the age of the oldest globular clusters:

    http://map.gsfc.nasa.gov/universe/uni_age.html

    “The oldest globular clusters contain only stars less massive than 0.7 solar masses. These low mass stars are much dimmer than the Sun. This observation suggests that the oldest globular clusters are between 11 and 18 billion years old. The uncertainty in this estimate is due to the difficulty in determining the exact distance to a globular cluster (hence, an uncertainty in the brightness (and mass) of the stars in the cluster).”

    Obviously you cannot have an 18 billion year old globular cluster and a 13.73 billion year old universe. There are several efforts going on to determine more accurately the age of the oldest globular clusters:

    http://www.stsci.edu:8082/jwst/science/drm/pdf/drm12.pdf

    Some other estimates are here:

    http://www.astro.ucla.edu/~wright/age.html

    “Chaboyer (1997) gives a best estimate of 14.6 +/- 1.7 Gyr for the age of the globular clusters. But recent Hipparcos results show that the globular clusters are further away than previously thought, so their stars are more luminous. Gratton et al. give ages between 8.5 and 13.3 Gyr with 12.1 being most likely, while Reid gives ages between 11 and 13 Gyr, and Chaboyer et al. give 11.5 +/- 1.3 Gyr for the mean age of the oldest globular clusters.”

  207. 207.   joe Says:
  208. 208.   kodkultur » Blog Archive » Universum blev plötsligt 13 miljarder år gammalt Says:

    [...] Bad Astronomy och NASA ska den korrekta åldern på universium vara ca 13 miljarder år. Men som en klarsynt [...]

  209. 209.   Orjeej Says:

    Science has been and always will be about explaining how not what or why. This is fundamental to understanding science. What is gravity? This at least as far as I can determine is not a question a science seeks out. How does gravity interact with other forms of energy? Would be more along the lines of science. I am a biologist by education and most questions that I have come into contact with are along the lines of how. How is DNA formed? How does DNA effect an organisms developement? By finding answers to these questions through observation you can get a picture of what DNA is but you cannot ask what it is and hope for an observable answer.

    So @joe
    Science is like working on a quilt and relies only on what we can observe. If the things we can observe are redshift/background noise then it is reasonable that we would focus on these observable and testable phenomenoms. If these a hypothesis contradicts a theory then scientists as KD points out constantly modify theories to better explain observable events. So theories that are largely proven form the center of the quilt and those unproven form the edge of the quilt. In my studies evolution is largely accepted and only question of how the exact process works are being sought out. Isn’t science grand.

  210. 210.   Seoulscapade » Blog Archive » Monumental News, Minor Ripple in the Newsiverse Says:

    [...] other main WMAP results, as summarized by Phil Plait, the astronomy, writer, and skeptic from the Bad Astronomy sit: A lot of this information was determined a while back, just a couple of years after WMAP [...]

  211. 211.   Mike Seattle Wa Says:

    So every thing started with the big-bang..I have but one question. What was there b4 the big-bang?
    Science says we can’t create matter or energy. We just change its form.

  212. 212.   sanjay mathur » Blog Archive » Bad Astronomy Blog » The Universe is 13.73 +/- .12 billion years old! Says:

    [...] Bad Astronomy Blog » The Universe is 13.73 +/- .12 billion years old! , NASA – WMAP Mission [...]

  213. 213.   Heber Rizzo Says:

    Dear Phil:

    May I translate this article into Spanish and publish it in my blog, with recognition and link to the original, of course?

    NOTE: I usually translate (duly authorized) from many sources, like Universe Today, ESO, NASA Science, etc, something you can check just by asking friend Google.

  214. 214.   joe Says:

    Orjeej/KD/others: ” Whichever it is, I’d claim that it is a failure of general education: too many people don’t understand the scientific method. The scientists, I assure you, do understand it.”
    Even in scientific journals you commonly see wording that is entirely based on, for example, the existence of dark matter. So as ‘the quilt is being built’, there is a (small?) chance that the outer patches are attached to inner patches that are sew with bad thread. The whole quilt can fall apart, which wouldnt be so bad if it were discovered early.
    But what a terrible waste of all those years of ‘nice’ work on top of (based on) bad work! Whatever the odds are that the foundation
    (BB,redshift solely doppler, dark matter being ’special’) is wrong are the odds that most subsequent work is 100% wasted. For example, What if DM is ‘ordinary?’ matter? : http://www.scienceblog.com/cms/dark-matter-mystery-deepens-cosmic-train-wreck-13954.html ABSTRACT
    This paper, the “Particle Chamber “ theory, examines and identifies microscopic, dust like, matter as the mechanism that causes the gravitational effect known as dark matter. The initial analysis identified how these particles are distributed around our solar system’. Minute particles of matter are each contained in cubical chambers one kilometer on a side…
    This is all about the ‘not seeing forest for trees’ syndrome. Part of its
    nature is that everyone assumes that its is just unthinkable or impossible that its all wrong because everyone is running with it.
    The somewhat effective self-regulating mechanism is limited to
    individuals that happen upon undeniable contrary evidence (unlikely since they are usually wearing the ‘filter’ of the preferred theory) and those few that conciously and intentionally work on alternatives. The problem is they are such a minority that overall the culture can easily overemphasize one theory over the other. NOT because it is NOW the best fit. But because in the PAST it was the best fit.

  215. 215.   Robert Says:

    As soon as I read this (this morning) I shared it with my son. He was delighted at the news, but when I told him about dark matter/dark energy, he was overjoyed. Why? Because when he gets to college, he says, he doesn’t just want to _learn_ about these things, he wants to be one of the ‘guys’ (as he says) who learns about these things by studying the universe, and then gets to teach the other ‘guys’ about it (in adultspeak, an astrophysics researcher).

    You see, he’s only ten years old, and he was worried that everything would have been discovered by the time he’s old enough. Now that he knows it will take more than eight years, he’s vastly* reassured.

    *Astronomical pun intended.

  216. 216.   Cusp Says:

    > Science says we can’t create matter or energy. We just change its form.

    Actually – it doesn’t say this

  217. 217.   Atheist.nu » Jesus Christ has outsourced prayer Says:

    [...] the Universe’s age is getting more and more accurate. It seems to be about 13.73 billion years old. +/-.12 billion years. Close [...]

  218. 218.   Born again Skeptic » Blog Archive » Why are we here Says:

    [...] Many people collaborate using the same rules, and instead of dancing to make it rain we are measuring the exact age of the universe.  Each person need not understand every facet of scientific knowledge to benefit from it.  But if [...]

  219. 219.   Mu Says:

    My big question in regards to the “proven existence of dark matter” is, why does it not influence our local gravity, and why do particles that are subject to gravity not get absorbed into gravitational wells (like our sun)?
    We have 4 -5 times as much dark matter as regular, nevertheless Newton’s laws of motion of the planets holds just looking at the regular matter. So the dark matter has to be diffused enough so that it’s gravitational pull is the same in every direction. Also, it’s particles, whatever they are, have to have an extremely high speed so they can fly through large massive objects without being trapped. And that speed can’t have any kind of “normal” distribution, or the slower particles would get trapped over time and throw off our observed gravity laws.
    But, if they are so diffuse, why do they still show an effect on the galactic scale? And, as a final question, does dark matter cross event horizons of black holes?

  220. 220.   zoe collis Says:

    wow, how did you know that it is the universe’s birthday today. Brilliant info.

  221. 221.   james Says:

    How long will it take NASA to do yet another prediction on how old the earth is. It seems every year they spend a couple million on this wasted project. Who really gives a flying fk except some overeducated, overpaid and for the most part completely useless astro physicist.

    No one else gives a crap. We just like to look at the pictures of space.

    NASA is lucky if they can land 3 out of 5 of their missions…
    thats less than 75% of the time. ENGINEERING FAILURE

    The shuttle was a big lie so they could play around with new idea… ENGINEERING AND FINANCIAL FAILURE

    If the universe is still expanding and the time it takes for radio waves to come back it would seem that all the data collected had expired before it even was stored for processing at a later time…

    Keep wasting money NASA.. Go launch your sky rocket I wanna see the big bang again.

  222. 222.   Junkmail #198, March 10, 2008 « xpda Says:
  223. 223.   Age of the universe « Mr Wever’s Blog Says:

    [...] Bad Astronomy Blog has a great overview of the universe’s story thus [...]

  224. 224.   Torbjörn Larsson, OM Says:

    We should be aware that modeling is new and interesting, but not necessarily predictive. Science is the process of deriving generalizations from the iterative testing of hypotheses through experimentation. WMAP is not, strictly speaking, an experiment and Astronomy is not, strictly speaking, a science.

    “Model” is a misnomer, as big bang is a theory and the concordance model makes the necessary predictions. WMAP is an experiment as it makes observations of an ongoing phenomena – it’s just not a lab experiment. Astronomy counts as a science, and can be strictly defined so by the same argument, we can do observations.

    And as for “dark energy” there are several candidates with connections to other theories and observations, so it isn’t just a parameter that enables the correct predictions.

    Also, it’s particles, whatever they are, have to have an extremely high speed so they can fly through large massive objects without being trapped.

    I’m not an astronomer, but as there are hypotheses that suggests dark matter helped the first generation stars directly (as opposed to gather matter for the first galaxies) I don’t think they don’t participate in massive objects. Dark matter candidates seems to be very massive and so very dilute, is all. (And of course they don’t bind or otherwise interact with other objects much.)

    And, as a final question, does dark matter cross event horizons of black holes?

    Why shouldn’t it?

  225. 225.   v3rlon Says:

    I have to ask about this…other studies have pointed to numbers around this, though some (even after this) still have the possible high end at 20 Billion years old.

    1. As someone else asked earlier, how does time as we know it even begin to apply in the early part of the model? That is a lot of mass in a little area. I guess it might be time as perceived if you were there. That is to say that if you were somehow watching the universe be created from outside the universe (yeah, I know, just grab an aspirin and bear with me), the first second of the universe as measured buy a clock inside the universe would not run the same as your wirstwatch. That is just the same as a second on earth is not the same as a second in deep space or a second at the event horizon of a black hole. The “time as measured if you were there, in the universe, as it was created” is my best guess, but that could be a MUCH different number than my watch would measure (if the batteries lasted a long time, anyway).

    2. 95+% of the universe is ‘dark energy.’ Scientists don’t know what dark energy is, or how it works, and no living person can see, hear, smell, touch, or taste it (and since BA is an atheist and a skeptic, it follows that no dead person can either). How can we claim with anything vaguely resembling certainty its effects on the systems were are using to measure the age of the universe? Isn’t our sample a bit skewed? Is the effect of dark energy constant? How do we measure it if we can’t measure it? Is it changing over time? The question, again, is that with better than 95% of the universe being composed of something with unknown properties (and how do we know its 95%?), how do we know that this ‘dark energy’ isn’t messing with our results?

    For the guy wanting info on the age of the earth, rocks on the surface of the earth test out to 3.8 billion years old (by comparing the radioactive decay of elements within the rock). Meteorites test out to 4.56 billion years old using the same methods. The latter is believed to be the age of the solar system.

  226. 226.   The age of the universe now known better than ever! | The Grumpy Old Techie Says:

    [...] This comes from our friend Phil Plait over at Bad Astronomy. The WAMP (Wilkinson Microwave Anisotropy Probe) was launched by NASA in 2001 in order to take the most precise measurements to date of the variations in the microwave radiation of the universe. This omnipresent microwave energy is actually an expression of the energy from the big bang itself and has been resonating ever since the birth of the universe. The WAMP has been cited numerous times before for providing cosmology with some of the best data avaliable on the origins and nature of the universe. [...]

  227. 227.   Otter Says:

    This may seem petty to some. I think It’s valid. There is only one universe. It’s the definition of the word. It’s not flat. It’s timeless. If you’ve discovered some other way to look at things or even managed to break on through to some weird “Other side” it’s still part of “the universe”. There is , by definition, no such thing as another universe. Trying to explain “everything” by some particular mechanism such as “the big bang” is intrinsically unatainable. The rate at which the known universe is expanding is accelerating? I’m just a layman, but dosen’t zero point energy theory explain that better than einsteinian “matter warps space” theory?

  228. 228.   Mu Says:

    And, as a final question, does dark matter cross event horizons of black holes?

    Why shouldn’t it?

    Sorry, I realize I phrased that badly, the question was, can dark matter come back OUT of a black hole, aka path through it.

  229. 229.   Cusp Says:

    >My big question in regards to the “proven existence of dark matter” is, why does it not influence our local gravity, and why do particles that are subject to gravity not get absorbed into gravitational wells (like our sun)?
    We have 4 -5 times as much dark matter as regular, nevertheless Newton’s laws of motion of the planets holds just looking at the regular matter. So the dark matter has to be diffused enough so that it’s gravitational pull is the same in every direction. Also, it’s particles, whatever they are, have to have an extremely high speed so they can fly through large massive objects without being trapped. And that speed can’t have any kind of “normal” distribution, or the slower particles would get trapped over time and throw off our observed gravity laws.

    Dark matter *does* govern our local motion – it is the very thing that keeps the sun and the earth orbiting the centre of the galaxy.

    The reason why it’s influence in the solar system is small is that the amount of dark matter in the solar system is small – the galactic dark matter is spread over the halo, not concentrated into the disk.

    Things don’t fall into potential wells – you have to get rid of angular momentum – dark matter has a problem doing this as it only interact gravitationally – so it doesn’t collapse.

    Next

  230. 230.   Torbjörn Larsson, OM Says:

    @ Mu:

    the question was, can dark matter come back OUT of a black hole, aka path through it.

    Oh. Same answer though, if other matter can’t (except as Hawking radiation), why should dark matter (except as Hawking radiation)?

    @ v3rlon:

    As someone else asked earlier, how does time as we know it even begin to apply in the early part of the model?

    But there isn’t just a model in the theory. The concordance model covers most of the time, but early spacetime isn’t well understood.

    Scientists don’t know what dark energy is, or how it works, and no living person can see, hear, smell, touch, or taste it

    We can measure its effects on the cosmological scale, and there are several hypotheses about what it is. As I noted earlier, this isn’t just a parameter in a model.

    How do we measure it if we can’t measure it?

    I think you have to specify how you want to measure it, if you mean anything over the cosmological effects that are used to establish its existence.

    how do we know that this ‘dark energy’ isn’t messing with our results?

    But the point is that it is messing with our results, and thats how we know about it.

  231. 231.   Chuck Heaton Says:

    One contributer asked “I just want to know what we think we know, versus what we know by proof.” I think that it is important to understand that there is no such thing as ‘proof’ in science. There is only disproof – if the observations do not match the the predictions and/or descriptions of a theory, then it is disproven. Well, not quite. Newtonian physics works phenomenally well when observations are limited to the ‘normal’ range of masses, velocities, and sizes. It worked so well, in fact, that humans could eventually make observations outside the range that Newtonian physics was formulated within. Hence, more encompassing theories (relativity, quantum, etc.), could be developed. I think scientists do themselves a disservice when they use terms like ‘proof’. What is important in science is how well a given theory matches observations and how useful it is in predicting observations that are not yet made. Science is a self-correcting process, in spite of the human frailties and motivations that sometimes slow down its progress. I believe it was Carl Sagan that pointed out that, unlike faith-based statements, which are held to be ‘true’ no matter what, scientific statements are always tentative and always remain subject to future observations, which may or may not contradict them.

  232. 232.   James Collins Says:

    First I wanted to thank JOE for his blog where he referenced my paper that identifies Dark Matter (The Particle Chamber Theory of Dark Matter). The paper was published on the WEB as a pdf file April 2007 under collinsconsultinggroup.com and can be accessed through Google under “Particle Chamber Theory”. (You need quotes or you get hundreds – look for the pdf file or the equations are flawed). JOE in a separate blog addressed the voids in the universe. My paper also references and calculates them but was based on 10 billion years for the age of the universe. At last, the age of the universe finally has a more definitive window 13. 7 billion years. Previously it varied from 12 to 14 billion years in various journals. To stay conservative in my paper, I used 10 billion years, though I referenced the broader accepted estimate. Using the updated number, 13.6 Billion years (low end), the total volume of space (in my paper) is now 2.5 times what I originally used. Since the 10 billion years I employed encompassed all known matter and dark matter and still had massive voids, the latest correction must be all void.
    Also in response to MU my paper starts off by estimating the density of matter surrounding our sun based on Ceplecha’s paper on the amount of matter collected on the earth each year from space. This matter is suspended in space surrounding the sun attracted by the sun’s gravitational field. Also the paper agrees with your assumption that dark matter is diffused. However your premise that the particles “have to have extremely high speed so they can fly through large massive objects without being trapped”, I believe might be based on the reports of large clouds of Dark Matter passing through one another without change.
    My theory explains this phenomenon. Each of the particles in a specific cloud of Dark Matter would have an identical velocity vector indicating the cloud’s direction of travel.
    Separate clouds of particles with different velocity vectors would pass through each other with minor probability of collision because of the ratio of particle size to volume (one microgram of matter in a chamber one kilometer on a side). The velocities of each particle in each cluster would be unaffected unless two particles (one from each cloud) collided –an extremely rare occurrence.

  233. 233.   Mu Says:

    Thanks for the explanations, it has been 25 years since my nuclear physics class, and quite obviously a lot of science has happened since.
    One problem I still have in my understanding, can dark matter particles collide with ordinary matter at all and shed energy aka become theoretically detectable (not going into the likelihood of observing the event)?

  234. 234.   Haibane.info » Blog Archive » reality is filtered Says:

    [...] on that scale are only 2/10 thousandths of a degree. But what’s more striking about this is the implication of how much we don’t see: The energy budget of the Universe is the total amount of energy and matter in the whole cosmos [...]

  235. 235.   josephbales.com » Blog Archive » Weird, short conversation Says:

    [...] it was true. Would he have accepted it as true? Would he have tried to witness to me? Would he have asked for my sources? I don’t know. Now I wish I had probed a little more to find out his [...]

  236. 236.   James Collins Says:

    Mu, you ask great questions and as to observing the event, I can do better and can send you to a picture of illuminated dark matter surrounding our earth. The following web referenced next holds a couple of Dark Matter blogs of interest.
    http://www.scienceblog.com/cms/dark-matter-who-needs-it-14069.html
    A very astute lady (Candice H. Brown Elliott) read my blog and my paper and submitted some great questions. I answered them in turn and was pleasantly surprised to learn of the Zodiacal light and gegenshein. See next WEB. http://en.wikipedia.org/wiki/Zodiacal_light
    This phenomenon has been recognized for centuries but never correlated with Dark Matter. When I created the” Particle Chamber Theory” of dark matter on the WEB, I was researching everything on mass. Zodiacal light emphasizes light reflection – albedo – not mass and didn’t register. However, their analysis of the one millimeter dust particles suspension of in a cubical space of eight kilometers sounds like a scaled up version of my mathematically based theory identifying Dark Matter (one microgram in a cubical space of one kilometer). I analyzed mass; they analyzed reflectivity and were concentrating on physical size. I expanded my analysis to include the universe. They indicate coverage around our sun. The pictures and the history are enlightening and the Zodiacal Light (illuminated Dark Matter particles according to my theory) can be physically observed in the photographs.
    I leave you with the following thought, using the principle of Occam’s Razor; the simplest solution may be the best solution.

  237. 237.   Jón Frímann Blogg » Sköpunarsinnar ljúga og blekkja fólk Says:

    [...] er um aldur alheimsins. The Universe is 13.73 +/- .12 billion years old! Five Year Results on the Oldest Light in the [...]

  238. 238.   Calling CQ » Blog Archive » 13.73 Billion Years Says:

    [...] found it easier to read this synopsis from Phil Plait, aka The Bad Astronomer who, when commenting on the age result said, “Some [...]

  239. 239.   ryansomma.com » Blog Archive » Science Etcetera Venusday, 20080307 Says:

    [...] to the Wilkinson Microwave Anisotropy Prob (WMAP), we now know, the universe is Flat (within a 2% margin of error) and 13.73 Billion Years old (+/-120 million years). How can something be “flat” within a two-percent margin of [...]

  240. 240.   Illiterate Withdrawal » Interesting Links #1 Says:

    [...] Figure Battles Designer The Universe is 13.73 +/- .12 billion years old! Clinton, Obama Put Middle Class On The Wrong Path To Prosperity Hilarious Ventriloquist Overhead [...]

  241. 241.   The Universe is 13.73 +/- .12 billion years old! Says:

    [...] I am about to explain the early Universe to you. I’ll be brief, but if you want to skip to the results, then go ahead. [...]

  242. 242.   Wie alt ist das Universum? Says:

    [...] und deshalb könnten wir hier jetzt Schluß machen. Aber zum Glück gibt es ja noch Astronomen und die NASA, die sich den ganzen Tag mit nichts anderem auseinandersetzen. Dank des dicken Budgets [...]

  243. 243.   Texas: From saved to doomed in just 6 hours! | Bad Astronomy | Discover Magazine Says:

    [...] Texas Board of Education creationist Barbara Cargill today proposed an amendment to the science standards saying that teachers have to tell their students there are different estimates for the age of the Universe. This is not even a veiled attempt to attack the Big Bang model of the Universe, which clearly, and through multiple lines of evidence, indicates the Universe is 13.7 +/- 0.12 billion years old. [...]

  244. 244.   Texas wrapup: Yup. Doomed. | Bad Astronomy | Discover Magazine Says:

    [...] ages", she means 6000 years. This belief in a young Earth, is, simply, dead wrong. We know the Universe is 13.7 billion years old, and the Earth, while younger than that, is still 4.55 or so billion years old itself. This is not [...]

  245. 245.   Evolution Education in Texas Round-Up: “The Sidestep” | The Starnes Says:

    [...] ages”, she means 6000 years. This belief in a young Earth, is, simply, dead wrong. We know the Universe is 13.7 billion years old, and the Earth, while younger than that, is still 4.55 or so billion years old itself. This is not [...]

  246. 246.   Terry Says:

    Given that the stated age of the universe is 13.7 billion years old, what was before the beginning?

  247. 247.   Roger Says:

    wonder why care this much about the age of universe while our age is more or less 100 years and death comes all of the knowledge accumulated is take away! what’s the point then? or is there anything that can be taken by us after death? though we like to avoid, let us not be afraid of death otherwise, life has no meaning! just like light has none without the darkness!

  248. 248.   Michael Says:

    Very cool. Not to be a weiner, but the first paragraph refers to the big bang as the most distant [source of microwaves] there is. Assuming this is relative to Earth, that makes it sound as if the big bang was not a spherical event, but a planar(?) event. I have sort of been going with the spherical version: Am I totally off base?

  249. 249.   New Skeptic » Blog Archive » The Comfort of untruth - Just another WordPress weblog Says:

    [...] purpose of this post, however, wasn’t to give the evidence that the Universe is old– we have plenty of that. No, I wrote this to point out that the forces of ignorance are always there, 24 hours a day. They [...]

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