The galaxy that shouldn't be there

By Phil Plait | June 27, 2012 6:58 am

It’s generally said that discoveries in science tend to be at the thin hairy edge of what you can do — always at the faintest limits you can see, the furthest reaches, the lowest signals. That can be trivially true because stuff that’s easy to find has already been discovered. But many times, when you’re looking farther and fainter than you ever have, you find things that really are new… and can (maybe!) be a problem for existing models of how the Universe behaves.

Astronomers ran across just such thing recently. Hubble observations of a distant galaxy cluster revealed an arc of light above it. That’s actually the distorted image of a more distant galaxy, and it’s a common enough sight near foreground clusters. But the thing is, that galaxy shouldn’t be there.

This picture is a combination of two images taken in the near-infrared using Hubble. The cluster is the clump of fuzzy blobs in the center left. The small square outlines the arc, and the big square zooms in on it.

The cluster is unusual. It’s at a distance of nearly 10 billion light years away. Clusters have been seen that far away, so by itself that’s not so odd. The thing is, it’s a whopper: the total mass in all those galaxies combined may be as much as a staggering 500 trillion times the mass of the Sun, making this by far the most massive cluster seen at that distance.

But that arc… First, things like this are seen pretty often near clusters. They’re gravitational lenses: the gravity from the cluster bends the light from a more distant galaxy in the background, bending its shape into an arc. See Related Posts below for lots of info and cool pictures on these arcs. In this case, I’ll note the shape of the arc implies the biggest galaxy in the cluster, the one right below the small square, is doing most of the lensing.

But here’s the problem: the galaxy whose light is getting bent has to be on the other side of the cluster, and that cluster is really far away. Note only that, the galaxy has to be bright enough that we can see it at all. Combined, this should make an arc like this rare. Really rare.

So rare, in fact, that it shouldn’t be there at all! The astronomers who did this research worked through the physics and statistics, and what they found is that the odds of seeing this arc in this way are zero. As in, what the heck is it doing there at all?

Now we have to be careful here. What we have is one observation of one arc, and it happens to be behind an extraordinarily massive cluster. It’s hard to extrapolate exactly what this means. Maybe galaxies formed more vigorously than we thought in the early Universe, so there are more than we might suppose. Maybe it’s a huge coincidence, with a bright galaxy behind a massive cluster. Maybe the galaxy in the cluster doing most of the heavy lifting is surrounded by more than the usual amount of matter, making it an even stronger lens. Interestingly, using the arc itself, astronomers calculated the mass of that one big galaxy is something like 70 trillion times the mass of the Sun, making it bigger than most entire clusters at that distance!

If you get one weird thing happening, you might be able to shrug it off as coincidence. But two? In this case the existence of the arc at all coupled with the huge mass of this galaxy and cluster make me think there’s more going on here than we see. Still, it’s not clear what it might be.

One thing we can’t dismiss is that our models of the early Universe might be wrong. Well, we know they’re not perfect, so the question is really, how wrong are they? I expect we’ll be hearing from people who think Big Bang cosmology itself is wrong — and I’ll be clear: it isn’t. Those people are.

I also expect we may hear from people who don’t like the idea of dark matter, either. This is the mysterious stuff that we know is out there — and yes, we know it’s out there — that appears to have something like 90% of all the mass in the Universe. Our models of the early Universe depend on this stuff, and this new result may throw a monkey in the wrench for that. We do know there’s a lot about dark matter we still don’t understand yet. But this arc doesn’t mean we have to throw out all of dark matter theory; just that we may yet have some tweaks yet to go before we understand the Universe better. It would take a lot more than just a few odd examples before we’d be ready to dump an idea like dark matter that goes a long, long way to explaining so many other things.

But therein lies the beauty of all this! Old models do get overthrown, and we’re willing to do it once the evidence is strong enough. This gravitational lens observation is not enough to do it, but it may be part of a bigger picture that will. Or, more likely, there’s a simpler explanation that we just don’t know yet.

After all, this is science! If we knew everything already, we wouldn’t be doing research. There’s a lot about the Universe we have yet to understand. That’s why this is so much fun.

Image credit: NASA, ESA, and A. Gonzalez (University of Florida, Gainesville), A. Stanford (University of California, Davis and Lawrence Livermore National Laboratory), and M. Brodwin (University of Missouri-Kansas City and Harvard-Smithsonian Center for Astrophysics)


Related Posts:

Funhouse galaxy
Galaxies swarm and light bends under dark matter’s sway
Dark matter, apparently, is midichlorians
The galaxy may swarm with billions of wandering planets

Comments (87)

  1. Powerdroid

    I don’t get it, Dr. Plait. Is that hazy, bluish area definitely an arc? I don’t have the experience in these things, but the arc isn’t obvious to a casual observer like myself. And if it is one, I still don’t get the significance. The cluster is really, really far away; got it. The arc is beyond that; got it. Why is this statistically improbable? I’ll wait for someone to illuminate me.

  2. Chris

    Hmm, I tried looking at this location in Google sky using the WMAP feature. I was curious if there was a massive cold or hot spot which maybe could account for this. I didn’t see anything, but curiously before I could look around it crashed on me twice. So what is being hidden there that “they” don’t want me to know about?

    Who is knocking at my door?

  3. Jesrad

    What if all the ‘dark matter’ we’re trying to look for around us, is actually plain old matter that is moving away from us faster than the speed of light – and always has been – but is running away from other distant galaxies at less than the speed of light and thus still interact with them ? Could there be a huge or infinite amount of such matter just beyond our relative ability to interact with ? Could the limits of the universe just be another kind of event horizon ? Maybe the cluster’s light we see here only became visible by us through the gravitational lense ?

  4. Thorne

    Wouldn’t it be likely that you would find super-large galaxies and clusters early in the universe? All of that matter condensed into a comparatively small area would, it seems to me, tend to clump up in larger groupings. Which might also explain the apparent size and brightness of the arc, too.

  5. Daniel

    @1. Powerdroid.

    For me, this quote from the NASA article helped clear it up. What I took was: clusters can be that big, but finding them that faraway/old is improbably rare…and bright galaxies exist, but finding them that far away/old and clumped is also improbably rare…the two combined is mind-boggling.

    “When I first saw it, I kept staring at it, thinking it would go away,” said study leader Anthony Gonzalez of the University of Florida in Gainesville. “According to a statistical analysis, arcs should be extremely rare at that distance. At that early epoch, the expectation is that there are not enough galaxies behind the cluster bright enough to be seen, even if they were ‘lensed’ or distorted by the cluster. The other problem is that galaxy clusters become less massive the farther back in time you go. So it’s more difficult to find a cluster with enough mass to be a good lens for gravitationally bending the light from a distant galaxy.”

  6. Doug Little

    Phil could you outline the original cluster as well I’m having a hard time seeing it, everything is pretty much faint fuzzy blobs. I think I know where it is but I can’t be sure.

  7. Papabear

    Why are the masses of entire clusters determined by the weight of just one star (our sun)?

  8. Kim

    To understand how improbable that is, check out the Related Posts links and see what usually appears when you see large clusters nearby – nearby means 5 billions light-years, not 10 as with the one above. These large clusters have a lot of chance to pass in front of galaxies much farther away and bend its light.

    Now, look at the above cluster. It is already very distant, and you wouldn’t see any arcs because there weren’t many bright galaxies in the earlier universe. Still, there it is. If we can see a bright galaxy that far out, either the scenario is unlikely, or there are lots of galaxies like that that we didn’t account for.

  9. Artor

    Is it possible that this structure is a filament of galaxies instead of a lensing effect? Or is that even more unlikely to see?

  10. Dave

    @Thorne:

    When the Universe was young, it was more homogeneous. As it has aged, gravity has caused what were originally small overdensities to collapse further and to accrete more matter. So, the largest collapsed structures in the Universe today tend to be much larger than the largest collapsed structures were in the early Universe. This is why finding an extremely massive galaxy when the Universe was still young would be surprising.

  11. What I don’t like about dark matter is that so many people talk about it as if that’s actually what it was. 90% of the matter in the universe is unknown mystery stuff, I’m OK with that. In fact I kind of like it; it keeps us humble. Someone gave it a name and now many partially informed people talk about dark matter as if we know what it is and that’s the name for it. (Not here obviously).

    One of the things I love about science is that we still know so little despite how much we’ve learned. Most of out basic knowledge of the universe is more or less wrong, but we keep trying to get closer to the truth and we keep getting closer.

  12. Gaebolga

    @ Phil,

    I think you’ve got a grammatical error here:

    “…on the other side of the cluster, and that cluster is really far away. Note only that, the galaxy has to be bright enough that we can see it at all.”

    [Emphasis mine; italics in original removed for clarity]

    I think it’s supposed to be “Not.”

  13. Wzrd1

    @7, Artor, a filament of galaxies being visible that far out is even MORE unlikely. For one thing, one is nearing the edge of the visible universe. The inverse square law being the other issue. A galaxy is bad enough, a GROUP of galaxies would be far worse, as even MORE distance is involved.

    @Phil, “It’s general said that discoveries in science tend to be at the thin hairy edge of what you can do”, I disagree. Many discoveries in science start with, “Hmm, THAT is interesting!” ;)

    @9, VinceRN I have less heartburn with simple dark matter being dust, gas and occasional bodies (dark dwarves, rogue planets, etc) than with some subatomic particle providing 90% of the mass of the universe, obeying rather strict patterns of movement, yet is utterly unobservable. I’d have less heartburn with a variable cosmological constant, which would give me an ulcer!

    My first thought of the enlarged section was, OK, a object right behind the foreground being gravitionally lensed… No. Angle is wrong. Perhaps a more foreground object? No, no object closer is visible or distorting the other objects at that same angle or close to it. How about (a half dozen other things)… No. How about I read the article… ;)
    After reading the article, I thought, “Hmmm, THAT is interesting!”

  14. Sam H

    You can bet the creationists are gonna be all over this :)

  15. SkyGazer

    The Monster That´s NOT There Being Promoted By christain Schools As Real… only to demote Darwin:
    http://www.scotsman.com/the-scotsman/scotland/loch-ness-monster-cited-by-us-schools-as-evidence-that-evolution-is-myth-1-2373903

    Read it and weap.

    yeah yeah I know it´s of topic, but still it´s about things that are not supposed to be.
    Bite me.

    And a bit of personal rant: nice hey how those “upright” people twist and lie blatantly.
    Point your finger at a “religious” person and I´ll point mine to a lying hypocrite.
    (as a Eropean I´ll still want to make use of your law of “free expression”. Thanks.)

  16. Satan Claws

    @DougLittle (5): Have a look at figure 1 in http://arxiv.org/pdf/1205.3788.pdf This is the actual preprint.

  17. Andy A

    What you’ve spotted there is clearly the Nexus from Star Trek Generations,
    the likeness is uncanny.

    This link probably won’t come out at all, but if it does see here:

    http://images.wikia.com/memoryalpha/en/images/1/1b/Nexus2371.jpg

  18. Mike

    More like a typo, Gaebolga. And a spell checker won’t spot it, ’cause “note” is a word. He meant to type “not” but habit made him add the “e” at the end.

  19. GalaxyGregg

    @Powerdroid

    Perhaps I oversimplify it- but the main reason this is so statistically improbable is because at that distance things are incredibly old, even compared to the age of the universe. For something that big to be that old means it formed before we thought the universe was forming things like that.

  20. Giffy

    Maybe it’s Bolder’s Ring?

  21. Gollum

    My precious…

  22. Wzrd1

    @SkyGazer, I will merely note, when one points a finger, four fingers point back at the pointer.
    Hence, I let others point. :)

  23. Infinite123Lifer

    From a commenter on a previous post, BAFact math, Give him an inch and he”ll take a light year

    1. Nicholas Says:
    June 18th, 2012 at 10:33 am
    And that’s only a fraction of the observable universe.
    More Math:
    The observable universe is about 13,700,000,000 Light years.

    37. Infophile Says:
    June 18th, 2012 at 6:49 pm
    @1 Nicholas:
    It’s actually even bigger than that. Thanks to the fact that the universe is expanding, things that we see at the limit of visibility have since moved significantly farther away from us. The math is way too complicated to do here, but it works out to being about 46 billion lightyears, about three times larger than simply the age of the universe x the speed of light.

    After re-reading what Infophile has wrote I see that Infophile is saying that when an object’s light reaches us after a 13.7 billion year trip, that SINCE THEN it has undoubtedly moved a great deal.

    I suppose if the “galaxy that should’nt be there” (no name yet for galaxy GTSBT? :) ) were farther away than the edge of the observable Universe than the light still would not have reached here, but what if there were another umpteen billions of light years of Universe behind all those red-shifted galaxies . . . in what could be the unable to observe part of the Universe?

    Does the existence and nature of something like this GTSBT suggest that the Universe might be even bigger than we can see? Where something like GTSBT had plenty of time to form?

    If the Big Bang produced a big bang in all directions, well, our observations would be like measuring the radius of a circle and not its diameter, which would still mean that if there were a point of origin than the age of the Universe would still be the diameter of it cut in half.

    Also, I am looking for a frame of reference for 500 trillion . . . nope don’t have one, its bigger than I think I am capable of imagining :) I thank myself for playing though

  24. SkyGazer

    22. Wzrd1
    Consider it done. (but as I said: only as a personal note, I will not point on behalve of others and as I said I only point second)
    ;)

  25. SkyGazer

    Ow and on another note:
    whooping cough has doubled this year in the Netherlands(in olny the first six months) compared to the whole last year.
    Article is in dutch, but you can googlelate it:
    http://www.telegraaf.nl/binnenland/12444727/__Onverwachte_piek_in_kinkhoest__.html
    So some are “winning” …

  26. Poul-Henning Kamp

    Do we know for sure that the arc is lensing ? Couldn’t it be ejecta ?

  27. Chris Winter

    This is maybe just a newbie goof on my part, but is it definite that the arc really is beyond the huge mass that’s doing the lensing?

    What I’m getting at is, could the gravitational lens be so strong that it’s warping light around from a source that’s closer to us than it is?

  28. Y’know, a question just occurred to me that I haven’t asked before. If we’ve determined that we are 13.7 billion light years from the spot of the Big Bang, that implies (or I can infer) that we are at the universe’s edge, that there is nothing beyond our galaxy from the BB site. Am I understanding this correctly? Or is there, say, 1 billion light years between us and the edge of the universe (and how would we know)?

    It doesn’t seem to me that we are anywhere near the outer edge of the universe. However, we are looking back to the center and find objects that are 12 billion years old. If the universe is 13.7 billion years old, that means that there are no more than 1.7 billion light years of matter beyond our solar system (from the center of the BB). Correct?

  29. SkyGazer

    @26. Chris Winter

    Look at the post about Andre Kuiper (think of him as the arc) and his waterbubble in front of his face (ie that massive cluster). His face looks distorted. Now imagine that same bubble (cluster) behind his head (the arc). Et presto a total normal head with an invisible bubble behind it.

  30. Jon Hanford

    @Poul-Henning Kamp:

    “Do we know for sure that the arc is lensing ? Couldn’t it be ejecta ?”

    According to the paper (see link @16 Satan Claws) the possibility that the arc is not a lensed object but, say for example, at the same distance as the galaxy cluster, appears unlikely based on factors such as the arc’s color, curvature, length to width ratio and lack of color variation.

  31. Doug Little

    Satan Claws @16,

    Thanks, that cleared it up.

  32. SkyGazer

    What´s stranger is that everything moves away from us and get´s redder. However this is behind something red, thus farther away and it is blue… is it comming back to haunt us? Or is the blueish appearance due to the lensing.

  33. TheZark

    So far it’s been sounding to me like “this looks like a lensing arc so there must be a galaxy there”. Are there other types of objects that could look like this? Maybe a nebula? Or are nebulas not usually big enough? And are we sure that what we’re seeing isn’t closer to us than the cluster? Admittedly my astronomy knowledge is somewhat limited, so I may have missed some important facts. Is it impossible for us to know for sure what we’re seeing without studying it more?

  34. Mirror

    @30. Maybe we are looking back at ourselves

  35. Shawn S.

    Could another cluster close to it but a bit further away contribute to the effect? Maybe far enough away and positioned so as not be detected but exerting effects contributing to the effects seen at the nearer cluster?

    Or am I not even wrong? :D

  36. Torbjörn Larsson, OM

    That was hard going.

    I take it from the papers that the galaxy mass itself falls well within the LCDM model (“we were simply somewhat lucky”, p5 “SZ Measurement…”). So the standard cosmology has no problem out of this.

    But the arc is problematic to resolve.

    The only realistic resolution was that the dark matter halo concentration is higher than expected. The current distribution for that is a heuristic derived from simulations. To correctly predict local halos, the early halo concentration goes down compared to earlier heuristics.

    So the largest tension seems to be with the current state of the art in predicting dark matter behavior. That doesn’t seem too bad, should be exciting for those who work the area.

  37. JB of Brisbane

    @SkyGazer #32 – Could just be false-colour rendering. Original may not have even been visible light.

  38. Poul-Henning Kamp

    @30 John: But isn’t “unlikely” more plausible than “impossible” ? :-)

  39. #28 Barber:
    No, we are NOT “13.7 billion light years from the spot of the Big Bang”, because there was no “spot of the Big Bang”!!!
    The Big Bang did NOT happen at any particular location in space, from which everything is moving away – because there WAS no space at that instant! Space was infinitesimally small and infinitely dense, and as a result of the Big Bang, space itself is expanding, rather than something expanding into empty space. Galaxies are not moving away from some central location, as there is no central location or frame of reference; everything is moving away from everything else.
    Here in our Galaxy, it looks as if everything ( beyond our Local Group ) is moving away from us – but if we were in another galaxy a billion light years away, we would see the same.
    The Big Bang didn’t happen “somewhere” in space; it happened everywhere!

  40. Artor

    @Barber #28
    We haven’t established that we’re at the edge of the universe. If that were the case, half the night sky would be black. The 13.7 by distance is the limit of what we can observe, not the center of the universe, nor ground zero for the Big Bang. We have no idea where that might have been. As I understand it, (probably poorly), Wer’re not all being flung away from the bang, but it was space itself that expanded, carrying everything along with it. Thus, the center of the Big Bang is everywhere.
    To make it more confusing, the light we see from 13.7 by away was much closer when it shone, and the distance has stretched during it’s travel time.

  41. Jess Tauber

    “Big Bang” unfortunately is here to stay, when in reality it was the Great Rescaling. Space (time?) got bigger relative to mass and energy (which got smaller). Yeah yeah I keep hearing this doesn’t work at locally relevant scales because gravity holds things together, but that fails to explain what happens to the intervening distance between gravitationally bound bodies. You got two planets that expanding spacetime moves apart by some fraction of an atomic distance in time x. Are the bodies themselves expanding, and if not, then what? If we have to ‘eat’ that intervening spacetime expansion, and the bodies get a bit closer, maintaining their known distance (by local scale), doesn’t that energy have to go somewhere? Gravitons changing their ‘frequency’ the way photons do in similar circumstances? Or does this all get lost in the quantum universe?

    Actually the galaxy arc has me worried- where it the arrow it show (or was that the arrow of time?).

  42. Steve Morrison

    What´s stranger is that everything moves away from us and get´s redder. However this is behind something red, thus farther away and it is blue… is it comming back to haunt us? Or is the blueish appearance due to the lensing.

    Remember that “red shift” means the whole spectrum shifts in the red direction; this is very different from things simply getting redder. (As higher frequencies become red, the red frequencies become infrared.) Isaac Asimov once argued that the terms “red shift” and “blue shift” should be replaced with “redward shift” and “blueward shift”.

  43. David C.

    try and think of the BB as if it were a tea biscuit or loaf of raisin bread, with raisins in it;

    now you’ve put a yeast or baking soda / powder in the dough to cause it to expand;

    when you put it out in a warm spot it begins to expand, and the raisins move with the expansion of the dough;

    the dough is the Universe, the Raisins are the galaxies; so while they are all moving outward, it is the dough that is carrying them along, not the speed of the raisins themselves;

    ps I know a bit about yeast ;-) one of my favourite food groups when mixed with sugar and liquid ;D

  44. Ananth

    Good ol’ Hubble – still opening our eyes to new wonders & knowledge, two decades after it was launched.

  45. Alhazred

    Well, remember, you’re looking at the 3d universe which exists in a 4d space time continuum. SPACE is “finite but unbounded”, so there is no ‘edge’. In a crude sense you can think of a sphere. The expansion of the universe is like the sphere getting larger. It has a larger and larger surface area, but the SURFACE (the analog of our 3d space) doesn’t have edges. In theory there should be closed paths you can follow in a straight line that get you back to where you started, much like great circles on the Earth. When someone says “13.7 billion years ago this light was emitted” there are actually several different ways to measure a distance to that object. There is a ‘co-moving distance’, a ‘time of flight distance’, and some other ones that I am not entirely sure I fully even fully understand. Relativity starts to make things rather hard to understand by our common sense notions when you get to cosmic scales.

  46. David C.

    been away and it gave me time to think:
    If the JWST or either of the two spy telescopes recently given to NASA, don’t get funding, it may be another generation before a clearer picture of what this represents will become available to science; to me and I suspect to Phil and the rest of us, that will be a tragic slowing of scientific understanding of our Universe (or even the Multi-verse); being on the cusp of great discoveries in the colliders, we need a complimentary advance in technology in telescopes; certainly one can say we are under a constrained economy, but we aren’t going to bring advancement 50 to 100 years from now, if the basic research is not funded now; we are still riding the wave of investment from the early to middle 20th century; sadly the majority of investment around the world in the latter portion, was in the military; future generations will have much to say about that;

  47. Dave

    Is this a galaxy that no longer exists? One that was so powerful that it collapsed upon itself and exploded, then formed what is now seen around it?

  48. Diederick

    Do I read this right? The cluster is 500 trillion solar masses, the galaxy behind it 70 trillion solar masses. So we have a custer that is less than 10 times the mass of a single galaxy?

  49. Itskurtins

    Yes! That ark I have heard all kinds of speculation about what it might be: one of thoes massive first stars that started the whole metalisity thing off, one of the first galaxies, though they are not supposed to be so bright as this object. So every body waits for JWEST to launch and look back and see what was what. Think of JWEST as our last big science program, or lets hope its not our last one. And thank you to the poster who explained the BB so nicely. Neil H.

  50. @23 Infinite123Lifer I use seconds to break down time scales into something manageable. For example: 1,000,000 seconds = 11.57 Days, and 1,000,000,000 seconds = ~31.7 Years. So 500 trillion seconds is around 15854.9 millennia or ~15,854,896 Years. Though again at this point you come across the fact that your invoking a million to describe another number and it starts to lose its meaning again.

  51. MNP

    A day when statistical analysis is wrong. That, that is a good day.

  52. Joseph G

    Fascinating, really cool stuff!!
    Just curious, though: do we have any idea how our own galaxy “weighs in,” measured in solar masses? I’m just trying to get some landmark for comparison to a 70 trillion M☉ galaxy. Is that big? Heh, sounds like a strange question: “Is 70 trillion suns a lot?” Astronomy really demolishes one’s sense of proportion :-P
    But just to get an idea? I keep hearing 100 billion as an estimate of the number of stars in our own galaxy. Of course, we also have large stars and a supermassive central black hole, but my understanding is that something like 85% of the stars in the galaxy are less massive than our sun, soooo… 100 billion M☉ or thereabouts? Of course, that doesn’t take dark matter into account.

    EDIT: Teh Wiki sez 1 to 1.5 trillion M☉. Seeing as how the Milky Way is a larger then average galaxy already, 70 trillion M☉ is huge! Huger. More huge. Moar!!
    Sorry, I’m tired :)

    @47 Diederick : Do I read this right? The cluster is 500 trillion solar masses, the galaxy behind it 70 trillion solar masses. So we have a custer that is less than 10 times the mass of a single galaxy?

    I guess that’s what I’m trying to get a handle on. I get the impression that most galaxies are WAY less massive than 70 trillion M☉, but I’m not sure by how much…

  53. Joseph G

    @17 Andy: What you’ve spotted there is clearly the Nexus from Star Trek Generations, the likeness is uncanny.
    This link probably won’t come out at all, but if it does see here:

    Rats. We’re gonna have to destroy a LOT of stars to get it to come here :-P

  54. SkyGazer

    @ 37. JB of Brisbane
    Ah yes ofcourse. False colours might be the reason it is blue. Silly me.
    Thanks.

  55. scribbler

    Good point 28…

    Funny how there is no beginning point to the big bang and yet the Universe has an “edge”…

    Logic demands that IF there is a big bang (and I agree it does look that way ;-), we are smack dab in the middle of it; at Ground Zero, so to speak…

    To be clear, for it to take 13 billion years for the light to get to us, it had to be 13 billion lights years away to begin with…

    @3 I have often pondered what we would be able to observe in our realm of matter traveling faster than the speed of light. Reason would be that it would still BE there, it would still exert gravitational pull and yet, we would not be able to SEE it, would we?

    Sure would explain a lot…

    ;-)

    As for the state of our “knowledge” of the Universe, I stick with the philosopher who said that he was considered by the gods to be the wisest man on Earth because he knew that compared to the Infinite number of things to be known, we, collectively as humans, in reality know NOTHING…

  56. scribbler

    As for pointing fingers, in some of these “discussions”, I would be pointing only one and it would be pointing straight up with the other three pointing to the ground and the thumb tucked neatly over the index…

    ;-)

    (chuckle)

  57. Abiblr

    @phil and @all, may be….just maybe what the arc is part o the galaxy itself.

    this occurred to me ‘cos the foreground galaxy cluster is 500 trillion-sun heavy so it should have a huge rear-end (or posterior?)…and the arc may be just the arc forming from the farther part(s) of this posterior.

  58. BAC

    I don’t see anything telling us where in the sky this is. Does any one have a reference point?

  59. BN

    My question when I read stories like this involves the expansion of the universe (I am using universe to mean space, I understand that they can mean different things though) and the speed of light. My understanding/assumption is that if the universe is ~13 billion years old, then light reaching earth from objects at the limit of the observable universe originated ~13 billion light years away. Due to the expansion of the universe though, those objects may now be closer to ~50 billion light years away. In the ~13 billion years that the light emanating from those objects was traveling and the universe was expanding, would the light then have had to travel > 13 Billion light years or does the light expand with the universe as it travels through space or does the speed of light increase with time? What I mean by the speed of light increasing with time involves periods of time that are so large that the increase in the speed of light is not yet measureable. For instance (and I know that this is not exactly an accurate description because my understanding is that objects that are gravitationally bound to each other are not believed to be subject to the expansion of space), say that in 2 billion years that the space between the earth and the sun had expanded so that the distance between the two was twice the distance it is now. Would the light from the sun then take ~17 minutes to reach the earth, or would the speed of light have doubled so that it still only took ~8 minutes? Because, if it took ~17 minutes under those circumstances, expanding that premise to distances near the limits of the observable universe, would it not follow that light from an object that was 13 billion light years away 13 billion years ago had to travel more than 13 billion light years due to expansion? Or is expansion already taken into account when calculating distances of light received from those far reaches of the universe? If it is though, wouldn’t that mean that objects emitting light that traveled ~13 billion light years may have been less than 5 or even 1 billion light years away when they emitted the light? This still doesn’t even take into account superluminal expansion and what that could mean to perceived distances of objects that far away.

  60. Infinite123Lifer

    @Brian S:

    Ah time, it is always helpful for me when trying to get perspective on large numbers, I should have thought of that :) And yeah ~15,854,896 years does kiiinda lose its meaning. Maybe this, if I lived for 100 years every time than I would have to live approx 158,548 lifetimes. Imagining 150,000 lifetimes doesn’t really sink home either. I guess 500 trillion is just outta comprehension for me. Good try though

  61. Statistically it doesn’t exist, yet we have an image of it.
    Statistics can be misleading.
    Take coin tossing for instance, flip two coins and they will come up HH HT TH or TT the probability of guessing which pair comes up is fairly low, yet one of them will occur every time. Calling it in advance is tough but second guessing its probability in hindsight is meaningless. Same for the picture of the really very far away galaxy. Saying you’d find one probability apparently zero, but having found one, probability 100%.

    Personally I think somebody just found Waldo.

  62. @scribbler
    The Big Bang wasn’t an explosion it was the beginning of inflation. The light that we see now from these objects has been traveling for about 13.4 Billion years but because space itself is expanding it has taken this long to get here. The objects emitting that ancient light are now about 42 Billion light years away,because inflation is still happening and some think it is accelerating.
    Also, yes we are the center of the OBSERVABLE universe because we see equally far in every direction. Yet we can’t see the entire universe (Look up Hubble Limit). But since we can’t directly observe anything beyond the Hubble limit it is not discussed much, however we should be able to see the effects of large gravitational masses on stuff within our view.

  63. Kevin Walker

    We live in a giant optical illusion from which we are trying to make an escape.

  64. Kevin Walker

    Suppose that an intelligence evolved in a galaxy in the future where no other galaxies were within their optical view. They would think that the universe had begun as a soup of particles spread out over an infinite distance and through gravity had pulled together into their galaxy and that gravity would eventually crush into the black hole at the center and disappear. It all depends upon your current perspective. What we see isn’t necessarily what exists or even what always existed , it is only what we can see.

  65. Kevin Walker

    What we can see is so dated that it would be laughable if it weren’t so depressing.

  66. Kevin Walker

    Would galaxies even still exist in so distant a future where you couldn’t see light from other parts of the universe?

  67. scribbler

    @63 I’m with ya…

    About the Hubble limit, I use a thought experiment. We are at the center of the observable Universe. Let’s imagine a person standing at the edged of what we can see and the “darkness” beyond. In between us is the same section of Universe. We see it from one side and he sees it from the other. It is safe to presume that the Universe between us is pretty much the same as it is around us. Wouldn’t the Universe on the other side of him be the same as that which is in between us?

    I divide science into two camps I call “Reasoners” and “Empiricist”. A Reasoner does as I just have and presumes until proven otherwise, that the unobserved Universe on the other side of what we can observe is the same as the Universe around us that can be seen. An Empiricist will only think about and discuss what can be seen and measured. He will make no presumptions and will only state that we can’t see, so we can’t be sure and then deem the concept unworthy of consideration…

    A Reasoner sees a doorway in front of him that is darkened out, looks behind himself to see rooms through other doorways and presumes until proven otherwise, that there are rooms through the darkened doorway. The Empiricist says we cannot see rooms through the darkened doorway and will not discuss them. He then makes the mistake that since he finds no value in the concept of rooms through the darkened doorway that he defines the space beyond as having no rooms…

    To that end, I say that Reasoning demands that the Big Band is much larger than a roughly 26 billion light year sphere. If that is the case, all bets are off with the current Standard Model…

    Let’s say the real Universe is, for the sake of argument, 260,000,000,000 billion light years in diameter and is all, more or less, like it is around us. Let’s say that it has a center and everything is moving away from it. Now lets say that you pick any spot and draw a 26 billion light year sphere in it that does not intersect and edge, and you will get our observable Universe EXACTLY…

    ;-)

    With all due respect, in my opinion, Inflation is akin to Dark Matter. It is the realization by mainstream science of their MISTAKE and the quantification of that mistake to a degree to derive a “constant”, if you will. Inflation has not been proven to my satisfaction enough to even seriously consider it a reality. Reeks of “fudging” to maintain the status quo, to me…

    I prefer to stick with “We were wrong and we don’t know the nature of our mistake as of yet.”

    ;-)

  68. Nigel Depledge

    Scribbler (69) said:

    A Reasoner sees a doorway in front of him that is darkened out, looks behind himself to see rooms through other doorways and presumes until proven otherwise, that there are rooms through the darkened doorway. The Empiricist says we cannot see rooms through the darkened doorway and will not discuss them. He then makes the mistake that since he finds no value in the concept of rooms through the darkened doorway that he defines the space beyond as having no rooms…

    But your own definition of the Empiricist would not have him make this assumption – instead, he would say “we don’t know” and turn his attention to something that can be measured.

    To that end, I say that Reasoning demands that the Big Band is much larger than a roughly 26 billion light year sphere. If that is the case, all bets are off with the current Standard Model…

    The Standard Model is a particle-physics theory, not a cosmology theory.

    Let’s say the real Universe is, for the sake of argument, 260,000,000,000 billion light years in diameter and is all, more or less, like it is around us.

    Why?

    As far as we can tell, the universe is infinite.

    Let’s say that it has a center and everything is moving away from it.

    This is highly speculative. If the universe is finite, it is very likely to be unbounded (akin to the way the surface of a sphere is finite but unbounded, only the universe has more dimensions). If this is correct, then there is no centre. To draw an analogy, where is the centre of the surface of a sphere?

    Now lets say that you pick any spot and draw a 26 billion light year sphere in it that does not intersect and edge, and you will get our observable Universe EXACTLY…

    More or less, apart from the fact that our observable universe is far larger than 26 billion ly from side to side (due to the expansion of the universe and the finite speed of light).

    With all due respect, in my opinion, Inflation is akin to Dark Matter. It is the realization by mainstream science of their MISTAKE and the quantification of that mistake to a degree to derive a “constant”, if you will.

    But Inflation does make predictions that have been borne out by observation (the nature and distribution of the anisotropy of the cosmic microwave background, for example).

    Inflation has not been proven to my satisfaction enough to even seriously consider it a reality. Reeks of “fudging” to maintain the status quo, to me…

    Maybe so, but as far as we can tell, Inflation is a necessary component of any BB model that produces a universe that looks like ours. Occam’s razor tells us, therefore, to assume it is correct until we find evidence to the contrary.

    I prefer to stick with “We were wrong and we don’t know the nature of our mistake as of yet.”

    But this approach precludes the exploration of alternative theories as much as it precludes the exploration of the edges of our current theories. Theoretical cosmologists are always on the hunt for facets of a theory that can be empirically tested to distinguish it from other, similar, theories.

    To say what you propose is to wait for new evidence to come to light by luck. To say instead, “we know that our theory is an approximation, but how good an approximation is it, and is there any way we can distinguish it from other possible approximations?” encapsulates – IIUC, of course – modern theorertical cosmology. IOW, it is a search for observations that can be made to test the validity of various components of the theory.

  69. scribbler

    @ 70, I know that the Standard Model is particle physics and it is, in my opinion, off.

    I’ll let the rest of it stand as it is…

  70. erbite

    Powerdroid is a baby bird that wants to be fed one morsel at a time.

  71. scribbler

    I have time…

    @ 70: Sorry, I did miss use the term “Standard Model” above. I do think it is off too but I was shooting for something more akin to “cosmological model”. Brain fart… I was also guilty of simply scanning your post and then responding without full information. I apologize.

    If I may…

    70: “But your own definition of the Empiricist would not have him make this assumption – instead, he would say “we don’t know” and turn his attention to something that can be measured.”

    MeNow: While we may not know, it is pretty safe to presume until proven otherwise, that what lies behind the doors we can see also lies behind the doors we cannot see when stated as theory and not fact. I agreed that an Empiricist would say “we don’t know” and turn his attention to what can be measured. No offense intended at all but I think that you missed the subtlety that in so doing he ignores what is behind the darkened door.

    I’m with Einstein on the infinite Universe thing, I’m uncomfortable with it.

    I understand the concept of the “dots on a balloon of expanding space” but think it is unsupported. Space may be expanding but every device you use to measure it expands at the same rate as well, so how is it testable? I’m asking, not challenging (and yes, I did read through this time and will address the microwave issue below ;-)).

    The balloon thingy is a bad example in that it is a three dimensional model demonstrating a two dimensional concept, in my opinion…

    It we hold it as accurate of the concept, the center you seek is the center of the balloon…

    70: “More or less, apart from the fact that our observable universe is far larger than 26 billion ly from side to side (due to the expansion of the universe and the finite speed of light).”

    MeNow: The actual Universe is larger than the observable Universe for the reasons you state. Is that what you meant? Our observable Universe is defined by the roughly 13 billion years worth of light that has had time make it here for us to observe. That makes the observable Universe a sphere roughly twice that then, right? I understand that with the Inflation theory (which is not necessary for your point to remain valid) and with the actual movement of the objects that gave off the light that they have traveled, one way or the other, farther away in the time it took for the light to get here. Again, that makes the actual Universe larger than the observable Universe.

    70: “Maybe so, but as far as we can tell, Inflation is a necessary component of any BB model that produces a universe that looks like ours. Occam’s razor tells us, therefore, to assume it is correct until we find evidence to the contrary.”

    MeNow: You say we have to accept this “anomaly” to keep the works greased and I agree. I would just be more comfortable calling this a constant or something rather than using to support the theory of Inflation. Splitting hairs, I admit…

    70: “But this approach precludes the exploration of alternative theories as much as it precludes the exploration of the edges of our current theories. ”

    MeNow: How?

    70: “To say what you propose is to wait for new evidence to come to light by luck.”

    MeNow: I disagree and can proffer a way to test whether there is directionality to the expansion of the Universe. It came to me while watching a pendulum. The pendulum stayed in line while the Earth moved under it. The same principle dictates the use of gyroscopes. If we had gyroscopes sensitive enough, and set say, six of them (three would work but six would be better, I think) on a 2X, 2Y and 2Z axis arrangement, IF there is directionality as I propose, it should show up as a constant variation that could not be explained by the movement of the Earth/Sun/galaxy/cluster. IF there is Inflation, there would be ONLY the wobble accountable by the said movement above.

    Don’t have a clue who or how it would be set up or if it’s even doable, but IF we had that information, neither of us would have to speculate.

    To address the fluctuations in the background microwaves, I will ask a question: Is Inflation the only thing that will account for this?

    I thank you for your kind and thoughtful response!

  72. scribbler

    @ 70: Wow! Someone who reasons without attacking. How refreshing!

  73. Sakari Maaranen

    If new space was being generated everywhere at a tiny but approximately constant rate on the average, wouldn’t it appear like the universe was expanding at an accelerating pace? Wouldn’t it look like it started at an indefinitely small singularity even if it always was boundless? What proves that new space or new probabilities are not constantly produced everywhere and that’s why the universe appears to be expanding at an accelerating rate?

  74. Will

    @Below – When you look through hubble, your really looking into the past because light takes x years to get to the telescope, thus the name lightyear. If the theory of big bang is right, that massive of a cluster shouldnt have existed that early in the universe. Thats why it shouldnt be there.

  75. Will

    @Below – When you look through hubble, your really looking into the past because light takes x years to get to the telescope, thus the name lightyear. If the theory of big bang is right, that massive of a cluster shouldnt have existed that early in the universe. Thats why it shouldnt be there.

  76. scribbler

    @ 75, if you have a relatively constant number of tiny bits of space being produced all around us, you would have the appearance and the reality of a Universe expanding at a constant rate. If these “packets” were increasingly larger or increasingly more in number, then you would have the appearance and the reality of an accelerating expansion. If the rate of increase was constant, the acceleration would be constant. If the rate varied, the acceleration would vary as well…

  77. Sakari A. Maaranen

    @78, But even if these bits of new space and probabilities were approximately the “same size” and “same in numbers” per amount of already existing space, wouldn’t the universe appear to be expanding at an accelerating rate, because the more space you have between any two points, the more bits would be generated between them? There’s simply more space to generate the bits in. It would be kind of “interest on interest”. For example, if two points in space, X and Y, had a million miles between them, and in a period of time, N new bits formed between them to double the distance to two million miles, then in the next similar period, approximately 2N bits would form between the same points, X and Y, because they were now double the distance apart. This would mean that the observed distancing velocity had doubled. Now, this hypothetical space and probabilities generation could be accompanied by or be related to other spontaneous generation phenomena, such as vacuum energy, and could behave differently depending on whether it happened around dense energy fields, matter, or in free space. I would like to know what, if anything, is wrong with this idea?

  78. scribbler

    @ 79,

    In your example, yes the “bits” would be represented by: n 2n 4n 8n. That is no acceleration. An accelerating Universe would be: n 2n 5n 12n…

  79. scribbler

    @79, You hit upon what I see as a potential flaw in the idea that space itself is “Inflating”. I assert that IF space is inflating then it “should” inflate in all direction, more or less evenly. That would mean that to us, everything would remain more or less relative to everything else, or put simply, there would be no observable change. So, when those who adhere to this theory use the word “space”, they don’t really mean space as in space/time, they mean that the more or less “empty” space between planets and galaxies and such is inflating.

    In the balloon analogy, not only are the distances between the dots expanding, the dots are expanding. No relative change…

    This idea is very, very problematic and has begun to be rejected. I can even name the death knell: Dark Energy… ;-)

    As for the idea that all of space time inflated at some point in the past to even out our mathematics and to preserve our cosmological model, I don’t buy into that at all…

  80. Sakari A. Maaranen

    @80, Okay, perhaps I have misunderstood something, but according to what I have read, if the dark energy is modeled as a cosmological constant(a, the universe would expand exponentially, i.e. similarly to what I described earlier. Could you point me to an online source that explains the faster than exponential growth that you seem to be referring to? I was talking about x^t , where x>1, and t is time. The ratio of (x-1) to x would be the amount of “bits” generated per one unit of space over one unit of time. Isn’t this the kind of exponential (accelerating) growth that those models (a) are about?

  81. Some scepticism is called for: http://telescoper.wordpress.com/2012/06/26/clusters-splines-and-peer-review/ .

    See also http://telescoper.wordpress.com/tag/extreme-value-statistics/ which is from the same blog and discusses another thing to keep in mind in cases like this.

  82. scribbler

    I don’t buy into dark energy at all so I couldn’t direct you to any sites expressing an opinion one way or the other. I simply observed that while what you expressed is certainly expansion, it is not indicative of ACCELERATING expansion. The way you laid it out, the expansion is constant and unchanging.

    YES, the number of “packets” is increasing exponentially but the increase between any object in your example is always an increase by a factor of 2x…

    For the increase to accelerate, just to keep the math simple, it would have to be something akin to 2x+1.

    I don’t believe in dark energy any more than I do in inflation. I a certain though that this theory will displace the theory of inflation because it is “new”…

    I thank you for a pleasant exchange!

  83. BerndB

    How can we be sure that the galaxy whose light is being bent is more distant than the cluster doing the gravitational lensing? I mean, if the cluster is really that massive, is it not possible that light passing it is bent more than just a few degrees? Say, 150 or 160 degrees? Like the path of a comet passing close to the sun and then being flung back in a similar direction to where it came from. Wouldn’t that mean that the “lensed” object is actually closer than the lens and we are in fact looking “back” this way? So far, I have not read anything here that would rule this out.

  84. Sakari A. Maaranen

    @84, okay, we just used the word “accelerating” in a slightly different meaning. By the way, I had a typo in my equation. The ratio I mentioned earlier would be of course (x-1) to 1.

    @85, read for example: http://www.physicsforums.com/showthread.php?t=312375

  85. scribbler

    @ 86, ;-) You’re good!

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