Hubble digs deep to see baby galaxies

By Phil Plait | December 8, 2009 9:17 am

I haven’t heard much from the Hubble Space Telescope folks since it was refurbished earlier in the year. Maybe that’s because they’ve been busily working on putting together an incredible image, the deepest ever taken in the near infrared. Feast upon this:


[Oh yes, you want to click to embiggen that, or grab yourself a gorgeous
4.6 Mpixel version.]

Holy Haleakala! This picture is incredible. They pointed Hubble at a fairly empty region of space, one where very few stars are seen. Then they unleashed the new Wide Field Camera 3 (called WFC3 for short) on it, taking images in infrared wavelengths just outside what the human eye can see… and they let it stare at that spot for a solid 48 hours.

The result? This picture, showing galaxies flippin’ everywhere, some seen a mere 600 million years after the Big Bang itself. Because the Universe is expanding, distant galaxies appear to recede from us, and their light gets stretched out. This Doppler Effect — the same thing that makes the sound of a car engine drop in pitch when it passes you at high speed — changes the colors we see from these far-flung galaxies, so their ultraviolet light, for example, gets stretched into visible and even infrared wavelengths. What you are seeing here is actually more energetic light emitted by galaxies that’s lost energy traveling across the expanding Universe, so by the time it gets here it’s infrared.

So the colors are not "real" in this image; they’ve been translated into red, green, and blue so we can see them. The reddest objects in the image are most likely the farthest away, and may be as much as 13 billion light years away.

Thirteen billion. With a B.

hudf_wf3_detailLet me point out something: here is a zoom in on one part of this ultra deep field, from the upper left. I’ve marked three objects. The one in the middle is a star; even with Hubble stars are point-like sources. The light from the star gets bent a bit (diffracted) around the metal support structure holding one of Hubble’s mirrors in place, giving it that crosshairs feature (we astronomers in the know call them diffraction spikes).

But look, the object on the left, clearly a galaxy, has crosshairs too! And they’re centered right on the galaxy’s nucleus, meaning that galaxy has a very bright, star-like core. We see this a lot in galaxies, when the supermassive black hole that lurks at the heart of every galaxy happens to be actively and voraciously eating matter. As this material spirals in, it gets very, very hot, and emits vast amounts of light. We call these active galaxies, and they were common in the early Universe. Studying them gives us insight into what galaxies were like when they were young, how that monster black hole forms and changes over time, and how galaxies themselves are born, age, and evolve over time. How many active galaxies can you find in the bigger picture?

And that little red dot all the way on the right? It’s not possible to say for sure, but given its reddish color in the picture and the fact that it’s a tiny dot makes me think this is one of those extremely distant galaxies, an object whose light has been traveling for roughly 95% of the age of the Universe itself. Those photons have hiked for billions of light years, seen the Universe change drastically, slammed through dust and gas clouds, curved around gravitationally-warped space, all to finally fall into the waiting glass mirror of our eyes’ orbiting proxy in space.

And there are dozens of those red dots in this image, all full galaxies in their own right, shrunk in apparent size and stature by their mind-numbing distance. And there are thousands of other galaxies, too… and yet this image is small, covering an area of the sky only 1/15th the width of the full Moon — it would take 8000 30 million images like this to cover the whole sky!

That means that everywhere you look, any direction you may choose, there are thousands, millions, billions of galaxies lurking there, hidden by nearby stars, gas, dust, other galaxies, and the terrible scale of space and time of our ancient Universe.

Everywhere we look, there are treasures to unveil. That’s what science tells us. And that’s why I love it.

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (100)

  1. PG

    It’ll be fun to try and explain how a galaxy forms in only a few hundred million years!

  2. Jamie F.

    Thanks for the mindboggle, Phil!

  3. Just when you think Hubble can’t top their latest mind blowing image, they come out with another gem.


    Now if you’ll excuse me, I’ve got some gray matter to clean up.

  4. Scott

    Phil – You do a great job capturing the amazement and wonder I feel as well when pondering an image such as this. It is almost incomprehensible how large and old our Universe is when thinking hard about this image. Of course, it makes me wonder if some alien astronomers are looking at something similar, and seeing our entire Milky Way galaxy as just a few pixels on their image!

  5. James

    I was asked by someone a while back why I was happy with “just this *vague arm wave*” and why I didn’t need to fill a non-existent void with woo (my words, not theirs!). They weren’t satisfied with the answer as it involved the word “billions” a few times and people generally lose interest when they hear “billions” as it’s a difficult number to wrap your head around. Especially in this context.

    *This* is the reason. This mind-bendingly-huge universe is why. Until a person has looked up at the sky, through a good telescope, they don’t get it. When they do and they look away from the ‘scope and *shiver*, then they get it. ;o)

  6. LMR

    Correct me if I’m wrong, but I believe this video is from the data from the same image.

    This is one of my favorite YouTube astronomy vids:

  7. Michele Limon

    According to the caption the picture is about 2.4 arcmin wide, i.e. about 1/12 the diameter of the Moon, this make the image about 0.0016 square deg. It will take about 25,000,000 of such images to cover the whole sky.

  8. Jeremy

    5 times the width of the full moon??? that doesn’t seem like a small patch of sky to me.

    The picture from Universe today makes it seem like the deep field is from a MUCH smaller patch of sky than 5 full moons.

    I don’t know, maybe I’m wrong, I’m still pretty amatuer

  9. Ho, hum. Yet another emotionless, unfeeling, uncaring post from one of those “atheist scientists”. :-)

    On a serious note, how does the James Webb Space Telescope’s resolution compare to this? How much more detail would we get from that “little red dot”?

  10. MikeInLondon

    “8000 images like this to cover the whole sky”?

    The image from the HUDF covered one 13 millionth part of the sky. If it was only 8000 there would only be millions of galaxies.

  11. Derek

    “only 5 times the width of the full Moon”

    Now is that a full moon when it is low and looks the size of a Hummer, or high when it looks the size of a dime?

  12. J_w23

    Ehm Phil… The angular diameter of the moon is a whole lot larger than the field of aperature of the WFPC3… So please refrain, #4 MikeInLondon is right too.

  13. Tadas

    I cannot understand one thing :)
    You write “and yet this image is small, covering an area of the sky only 5 times the width of the full Moon — it would take 8000 images like this to cover the whole sky!”, but the moon angular size is ~30 arcseconds.
    Hubble site writes: This image is roughly 2.4 arcminutes wide.

    The image is simply amazing, I think I will go to a printshop to get this one printed.

  14. Roy

    Distances like that make light seem so sluggish. It takes more than a second to get to the MOON. That’s just peanuts to space.

  15. Hugh says the image is 2.4 arcminutes wide…

    Isn’t the moon like 30 arcminutes?

    That would mean this image corresponds to 1% (10% width * 10% height) of the moon’s area.

    Do I have that right?

  16. Navneeth

    I thought that some of those tiny red dots were hot-pixels.

  17. dave

    I defy anyone who’d tell me that there is not another civilisation out there somewhere. The number of other systems out there must be so unfathomably mind-boggling, its surely statistically impossible for another life-supporting planet NOT to exist!

  18. Joe Meils

    I guess I’m not wrapping my head around this properly… how is it that the universe came from the Big Bang (which I assume was more or less a single point in space) and we can look into the past by seeing farther and deeper… yet, no matter which direction we look in space, we can see these hot baby galaxies…

    Shouldn’t we be seeing the early universe as a (relatively) smaller object? A densely packed cluster of galaxies looking something like the opening title shot of “Cosmos”?

    Maybe my understanding of cosmological geometry is a bit FUBAR…. Could any of you wonderful brainy people tell me why the early universe is spread in 360 degrees around us?

  19. Roy

    @9 Think of an ant on the surface of an expanding balloon. The surface of the balloon is seen all around the ant. If you can imagine the same effect in more dimensions (as the surface of the balloon here is a sort of 2-d analogy), you’re closer to the right track.

  20. Roy

    @9 “which I assume was more or less a single point in space” Actually, there’s your problem. It wasn’t a point IN space, so much as it WAS space. There wasn’t anything to expand INTO, which our brains really dislike.

  21. D’oh! I misread the scalebar in the image (that’ll teach me to grab a low res version). I though it was 60 arc minutes, when it was 60 arc seconds. I was off by a factor of 3600! I fixed it in the post. Thanks, MikeInLondon (#4)!

  22. J. D. Mack

    The Stars Are So Big… I Am So Small… Do I Stand a Chance?

  23. Scott_from_MI

    Hey BA: If you draw a line through the two diffraction spikes you point out and follow it to the top-center of the image, the line hits an odd looking orange-blue galaxy. It sure looks like it has 2 bulges, but must just be juxtaposition of two galaxies or a merge/collision right? It just looks so very tidy in the full-size image. Very cool.

  24. David

    Oh, Derek, you…funny guy…you 😉

  25. dcsohl

    Hrm. Can’t delete a comment entirely…

  26. @Joe (#9): Things are spread around us because space itself has grown in all directions. Every observer can realistically place theirself at the center of an ever-expanding universe. The standard pedagogical example is to imagine drawing dots on an uninflated balloon, then watching as the (two-dimensional) space between them expands when you blow it up… from the perspective of a single dot, other dots are receding in every direction within the surface of the balloon. Our own universe appears to behave analogously, with galaxies embedded in a surface of *three* dimensions.

    “We inhabit an insignificant planet of a hum-drum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people.” —Carl Sagan

  27. Pareidolius

    All hair now standing on end. Awe inspiring and humbling image.

    Okay, the ad agency guy is gonna swing wide on this one and interpret Lawrence Krauss’ AAI lecture as regards’s Joe’s single point in “space”. I think that the “point” has expanded and cooled so it’s now become everywhere and everything. We’re not just “inside” the former singularity. We are it.

    Was that even close Phil? Anyone?

  28. I’ll add that I shouldn’t do math 1) five minutes after waking up and b) before I’ve had coffee.

  29. Roy

    Thanks for the update! I was a little confused…

  30. Re: Comment 28 by Phil Plait; what a way to activate your brain for the day!

  31. Alareth

    “It’s a big universe and we’re not” ~ Yakko Warner

  32. PaleGreenPantsWithNobodyInsideThem

    Is swearing on this blog not allowed? Sorry.

    Anyway, as I was saying. I’m just awed that only 600 million years after the big bang, enough matter has condensed to create thousands upon thousands of galaxies. Fricken incredible.

  33. ^^ Yeah, no swear words — that’s Phil’s single rule, so his blog can stay a bit family-friendly. I didn’t know this until a few weeks ago though. Wish he’d post it somewhere, preferably right by the comment box.

  34. This is a different image than the ultra deep field imaging that was done back in 2004, I assume?

    I have to admit that the whole issue of looking that far back to the time not long after the big bang kinda messes with my mind. It seems like we shouldn’t be able to see this stuff that far back because the light would already have “passed” us, since the universe is expanding slower than the speed of light (or I assume it would be) the light would have gone past our location shortly after the event (because we were not as distant) and we’d never catch up to it.

    However, from what I’ve read, it’s not that simple (or even close) because it’s not simply that the distribution of matter is expanding, space itself is expanding and the big bang was not a single event, but was the beginning of an expansion that continues.

    Still, that seems to throw my brain into an infinite loop, trying to really get a grip of how that all works. It still seems like we shouldn’t actually be able to look back that far, and also begs the question that if we can, then could we also look all the way back to just hours or seconds after the big bang? If not, why not?

  35. Gary Ansorge

    ,,,and from the physics archive blog, comes this addendum to Hubbles Far Seeing, a chance to actually detect the quantum foam structure of reality:

    Hubble. What a wonderful instrument. So much we can learn from it.

    GAry 7

  36. Ooooooooh….

    This also makes a great desktop background (resized, of course).

  37. Michel

    “Everywhere we look, there are treasures to unveil.”
    And we live “in the middle” of it.

  38. In the large image, at the top edge, nearly in the middle, is what looks like a double-cored spiral galaxy. Or perhaps two spiral galaxies superimposed. It / they have two bright centers, and arms.

    Could that be colliding galaxies, or is it one that has been distorted by some intervening gravitational object that has lensed it to appear to be be two galaxies? I wonder….

  39. Chip

    To paraphrase Hitchins, “Far more awe inspiring than a talking snake”.

  40. Richard

    My vote: More of this type of content and less crosses on wrinkled eggs.

  41. @Steve Packard,

    Actually, space can expand faster than light (and did so right after the Big Bang).

  42. Greg in Austin

    dave Says:

    I defy anyone who’d tell me that there is not another civilisation out there somewhere.

    There is not another civilization out there somewhere that we know of.


  43. @dave,

    I agree. I’m not going to take the time to count the number of galaxies in that photo, but let’s suppose there are 1,000. (That’s probably on the low side.) If this is representative of the Universe in general than there are 30 million * 2 * 1,000 galaxies in the Universe. (Times 2 because we need to fill up the skies of both the Northern and Southern hemisphere.) That’s 60 Billion galaxies! Each of those can have millions if not billions of stars. Even if a tiny fraction of those are both the right type of star and have the right type of planet orbiting at the right distance, there would be billions of possible places for life to arise.

    In short, to quote Contact, if it’s just us it seems like an awful waste of space.

  44. @Steve Packard (#34):
    We could look back to hours or seconds after the Big Bang, except that the universe was opaque until atomic recombination at about T=400,000 years. This opacity basically means that no photons older than the CMB will ever reach us, however we may yet probe beyond the surface of last scattering with gravity waves.

  45. Joe Meils

    Thank you all for the explanations… yeah, I keep forgetting that we are NOT outside of space, looking in, but are actually a part of it. (That keeps coming back to bite me in the butt.) I guess I shouldn’t feel too bad… Pohl Anderson made the same mistake in his ending to “Tau Zero” as I recall.

    Everyone keeps talking about how insignificant we all are in comparison to the rest of the universe. I’ve never seen it that way. I see us as some of the rarest, most wonderful forms of matter in the cosmos. Matter that has over immense time scales, arranged itself into forms that can reproduce itself, and that can sense the universe around it, and think about it’s place in the grander scheme. As Sagan said, “we exist in order for the Cosmos to know itself.” Or, to put it another way…


    Ha! Let’s see a spiral galaxy do THAT!

  46. Walter Zed

    Goodness, but that’s gotta be a LOT of turtles…

  47. Dave72

    1) If we’re looking at 60 arc seconds of our current sky at our ancient universe that was much smaller are we really seeing a bigger section of the ancient sky and is it possible that if we look deep enough we will find these same galaxies in another part of the sky from perhaps a different angle ?

    2) Are those galaxies still there ? Is there even a there, that we could put on a map and travel to in our minds ?

    The expanding balloon model doesn’t help me wrap my brain around this one.

  48. Caleb

    Wonderful image!

    This and a previous post make me think of a quote from Blaise Pascal:

    “What is man in nature? He is nothing in comparison with the infinite, and everything in comparison with nothingness, a middle term between all and nothing. He is infinitely severed from comprehending the extremes; the end of things and their principle are for him invincibly hidden in an impenetrable secret; he is equally incapable of seeing the nothingness from which he arises and the infinity into which he is engulfed.”

    Just to clarify, I don’t interpret Pascal’s statement as referring to creation ex nihilo but rather the seemingly infinite universe in which we find ourselves. I just find it refreshing to read timeless statements like this from great thinkers.

    Go Hubble and LHC! :-)

  49. @Dave72 (#46)
    1) Global expansion is angle-preserving, so 60 arc seconds will always be 60 arc seconds no matter how far into the past you look. However, a multiconnected universe would present multiple images of the same source, and thus appear much larger than it is.

    2) The galaxies aren’t still “there”, but the matter-energy comprising them still exists. They are now on pretty much the other side of the universe.

    To use the expanding balloon model here, you have to include a finite speed of light—like a straight line (arc of a great circle) being drawn at constant speed over the growing surface, starting at one point while the balloon is small and eventually reaching a distant point after a long time (and much expansion).

  50. Bjoern

    @Steve Packard and TechyDad:
    Actually, it makes little sense to say that the universe / space expands slower or faster than the speed of light. According to Hubble’s law, the further something is away, the faster it recedes from us; so when you say that “the universe expands at speed x”, what exactly are you talking about? A galaxy at a distance of 1 billion years? 10 billion years? etc. Do you see that saying that the universe expands at that and that speed is meaningless?

    The only way to talk sensibly about how fast the universe expands is to say at what *rate* it expands, i. e. in that and that time, its radius increases by that and that factor (actually, for the accepted value of the Hubble constant, it increases by 7% per billion years).

  51. Josh

    Dave72 – Even though this image captures light from a very ancient time in our universe, you have to remember that the objects that generated that light are still moving away from us. Therefore, this image captures a point in which these objects are a certain distance from us. Since these objects are now even farther away from us, it would be impossible for us to find them in another part of the sky at the same time, as it would mean that the object would have to be closer to us than it was previously in order for us to receive light from its future position at the same time that we are receiving light from its previous position. Not only that, but I’m pretty sure that means it would have also had to travel faster than the speed of light to do so!

    I’m by no means an astrophysicist though, so somebody feel free to correct my train of thought if it makes no sense.

  52. Dan

    “Every observer can realistically place theirself at the center of an ever-expanding universe”

    The part that bugs me is that if I look at a galaxy at the very far reaches of space, meaning I’m seeing it only a few million years (or so) after the big bang, then everything in my logical brain is telling me it should be CLOSER to us. Meaning I’m seeing light from it at a time when it and us were MUCH closer together than we are now, so how can it look so far away?

    The other thing that bothers me is that there should be an edge! I know there’s not; even if I transported myself to the farthest reaches of the Universe, there is no “barrier” (or restaurant, thank you Douglas Adams). But I want there to be!

  53. colorofjanuary

    Great post. It all still makes my brain hurt, but every now and then it’s great to have everything put into perspective. :)

  54. awesomekip

    Hmm. I wonder if Hubble could be used to get a more detailed image of an exoplanet, such as Fomalhaut B, using this method of pointing at it for 48 hours. If so, could other planets be imaged this way, such as planets in the Gliese 581 system that have only been measure by the tug on their star?

    According to ( ), the exposure time for the picture of Fomalhaut B was 11.4 hours. Would a 48 hours exposure result in a better picture?

  55. Evil merodach

    I’m I right in assuming that this image was taken towards the galactic south pole, through the local chimney? (

    Seems to me that that would the best way to avoid the gas and dust in the Milky Way’s disk. We’re lucky that we have these observational “windows” out beyond our galaxy.

  56. Those photons have hiked for billions of light years, seen the Universe change drastically, slammed through dust and gas clouds, curved around gravitationally-warped space, all to finally fall into the waiting glass mirror of our eyes’ orbiting proxy in space.

    And nobody thought to ask those photons if it was okay to slam a mirror in front of them. Tsk. Tsk. For shame.

  57. Radwaste

    For those of you who might still be confused about “square degrees” and so forth…

    If you stand in the middle of a perfect sphere, it’s easy to see that you can turn around 360 degrees and still be looking at the inside of the sphere; if you marked off the equator with a pencil, you’d rapidly find out that the line is the same distance, both in linear measure and degrees, if you made another full circle at an angle to the first one.

    For ballpark purposes, and to help visualize this, one angular degree is about five feet at 100 yards, and one minute of arc is about an inch at 100 yards. Yes, you can get picky and be more precise. The short story is that this leads to 3600 square arc-minutes in a square degree… and about 41253 square degrees on the surface of any sphere. It’s “about” because of PI. You knew that part.

    I bet a buncha people here could show more of the math, but this simple explanation will get you around the blog pretty well whenever anybody cites an angle. Cheers!

  58. I have heard it said that, no matter how powerful the telescope, we can never see back far enough to the Big Bang. This maybe a silly question, but why is that, especially if Hubble can image galaxies a mere 600 Million years after the Big Bang?

  59. tacitus

    Essentially because the Universe was opaque before about 400,000 years after the Big Bang. Before then the Universe was so hot that matter only existed as plasma, and the plasma absorbed energy at all wavelengths and thus no light could escape to eventually reach the end of our telescopes.

  60. Dan Gerhards

    The universe shortly after the big bang was too dense. Every photon that was emitted was immediately absorbed, so there is no light to detect. It took around a few hundred million years for photons to be able to move freely and begin traveling here.

  61. Mark

    I don’t believe this is a brand new image. I saw this same image during the summer at the Cleveland Museum of Natural History [Shafran Planetarium.] One of their astronomers [Jason Davis] showed us this image on the dome and told us that there could be – based upon this image and if memory serves – over 400 billion galaxies.

    I could be incorrect, but it’s still freaking awesome.

  62. Scott

    @gibson042 says “Things are spread around us because space itself has grown in all directions. Every observer can realistically place [himself] at the center of an ever-expanding universe.”

    I’m afraid this will only inflate the egos of those who already think “the Universe revolves around them”!

  63. Mark

    A question about cosmological redshift:

    As space expands, it stretches out the wavelength of photons traveling though it, thus decreasing their energy. Where does the energy previously possessed by the photons go?

  64. Frederic Dumont

    If the galaxies were created about 13 billion years ago, with the expansion of the universe, shouldn’t they be much, much further that 13 billion light years? Or are these other galaxies?

  65. MAC

    No swearing? Well, @^&#%$@^&%#!

    I think the easiest way to understand why we see galaxies in every direction we look is that, like reporters in Afghanistan, we’re embedded – just a part of the ever-expanding universe. Or at least this particular universe.

  66. J. D. Mack

    What’s going on in this part of the image?

    Are these three galaxies really as close to each other as they appear? Why is material streaming *away* from the other galaxies instead of towards them?

    J. D.

    (I’m presuming that it’s not possible to embed images in our posts.)

  67. tacitus

    As space expands, it stretches out the wavelength of photons traveling though it, thus decreasing their energy. Where does the energy previously possessed by the photons go?

    The energy of the photon doesn’t change. The change in wavelength is due entirely to the change in the frame of reference between where (and when) the light was emitted and where (and when) the light was observed. That difference in the frame of reference is caused by the expansion of the Universe. So the photon hasn’t changed in any way, it’s when and where we are observing it (as compared with its origins) that has.

    Relativity — don’t you just love it!

  68. tacitus

    If the galaxies were created about 13 billion years ago, with the expansion of the universe, shouldn’t they be much, much further that 13 billion light years? Or are these other galaxies?

    It’s been estimated that the most distant galaxies we can see are now about 46 billion light years away from us today due to the expansion of the Universe, and yes these are the same galaxies that we observe to be around 13 billion years away in terms of the distance the light has traveled in the Deep Field photos. (I hope I got the terminology mostly right!)

    There really wouldn’t be much point in using the actual distances in the present because we have no idea what those far distant galaxies look like today anyway. To look that far back into space is to go back in time.

  69. Asimov fan

    The BA wrote :

    “But look, the object on the left, clearly a galaxy, has crosshairs too …”

    Clearly? It looked awfully star-like to me esp. at first glance. But maybe that’s just because of the low resolution? (Looking at the image above not the embiggened version.)

    “And they’re centered right on the galaxy’s nucleus, meaning that galaxy has a very bright, star-like core. We see this a lot in galaxies, when the supermassive black hole that lurks at the heart of every galaxy happens to be actively and voraciously eating matter. As this material spirals in, it gets very, very hot, and emits vast amounts of light. We call these active galaxies, and they were common in the early Universe.”

    So that specific “quasi-stellar object” (to me in appearance! 😉 ) is “just” an Active Galactic Nuclei (AGN) galaxy then and NOT a full blown quasar? Or could it actually be a quasar? Can we be any more specific on its nature?

    (Nb. Yes I know that Quasars are just the most extreme examples of AGN but you know what I mean – I hope!)

    Did we get spectra here as well or just the image by any chance?

    In passing, I find it curious to note that the terms ‘quasar’ and ‘asteroid’ have similiar derivations – both coming from objects that (through small telescopes) appear “star-like”. (Quasi-Stellar Radio sources = QUASARS / asteroids =little stars or “star-like” if I remember correctly which I may or may not be doing..?) Yet one is an entire galaxy or its superluminous active core and the other is a tiny rock within our own solar system. One is a rock that is microscopically small compared to a star while the other is a hundreds of huge collection of millions of stars and clouds of star-forming dust and gas and black holes and so much more but both at a quick glance could be confused with stars.

    To me, that really says something about our initial perceptions and assumptions and the the need to find out more & observe more closely, about how easily we can fail to understand things with our limited comprehension of the scale of different object & also just how mind-boggling wonderful science and esp. astronomy is! :-)

    This picture powerfully reminds me of the earlier Hubble Deep & Ultra-Deep Field images and, again, I am in awe. This is just marvellous and … well words fail me.

    Thankyou Dr Phil Plait for posting this and explaining this and so much more so well. 😀


    PS. If anyone wants a good introduction or discussion of cosmology (the galaxies & universe & its formation, history, etc..) may I recomend Tim Ferris’es very readable and clear “The Whole Shebang’ as a great non-fiction book on this topic?

  70. There was a great article about Hubble in the Washington Post magazine this past Sunday:
    Although it didn’t make it into the article, the writer said in a separate posting that Hubble has only photographed (you might want to sit down for this) one percent of the sky!!!

  71. ZERO

    Make that 13.7 billion years!

    And isn’t that the Hubble Ultra Deep Field?

  72. It’s been estimated that the most distant galaxies we can see are now about 46 billion light years away from us today due to the expansion of the Universe

    So… does this mean that we can never see beyond13 billion light years (or so) away? So, for instance, assume that the whole universe is at least 46 billion light years across. Say that a star was born about 20 billion light years from us. Can we ever see it, or is it forever beyond our view because it’s farther away than the universe is old? (I realize that I’m simplifying matters a whole lot, but I hope the idea is clear.)

  73. scottb


    This new image is also discussed in a feature article in the Jan 2010 issue of Sky & Telescope magazine. It talks about the limitations of Hubble and how much deeper the James Webb telescope will be able to go.

  74. tacitus

    Say that a star was born about 20 billion light years from us. Can we ever see it, or is it forever beyond our view because it’s farther away than the universe is old? (I realize that I’m simplifying matters a whole lot, but I hope the idea is clear.)

    Correct, we will never see a star that is born that far away from us, it will forever be outside our observable universe. In fact, it’s going to get a lot worse than that in the far distant future because of the runaway expansion of the Universe. Eventually (in many billions more years) the Milky Way will be the only galaxy we will be able to see — even those galaxies that are just a few million light years away today will be too far away to see at all. The only exception will be Andromeda since it is heading in our direction, but well before that time the Milky Way and Andromeda will have collided and merged into one massive galaxy anyway.

    Imagine taking a ultra deep field photograph like Hubble did and seeing nothing but emptiness, blackness. We would know nothing about the Big Bang at all, and almost nothing about the true nature of the Universe at all.

  75. Jim B.

    Absolutely fascinating! Reading this and thinking about it is an incredibly humbling experience. Thanks, Phil!

  76. @Seamyst (#71):

    The answer to your question depends on the global expansion of space. Let’s model that as a function of time r_i(t) (in units of (length/time)/length), and examine a light beam traveling at constant instantaneous velocity c towards a “stationary” target whose distance at time t is d(t) and receding velocity (from expansion) is r_i(t) * d(t). If we further assume that r_i(t) is monotonically increasing, we know that the target will never be reached if r_i(t) * d(t) > c, establishing a cutoff horizon of c/r_i(t). So if the global expansion rate never falls below its present value of 74.2 km/s/Mp (, we will never see anything that’s happening now more than 13.2 billion light years (^9+light+years%29) away. But things are more complex for time-varying r_i(t), in which the cutoff horizon is also time-varying. And we appear to live in precisely that universe, with r_i(t) not only increasing in the current universal epoch but also *decreasing* in the distant past!

    Making a long story short, your question is answerable only after defining r_i(t), and I don’t know enough about current models to even guess. But we *can* say that the cutoff horizon only exceeds 20 billion light years while the universe is expanding at less than about 66% (*+10^9+light+years%29+%2F+%2874.2+kilometers%2Fsecond%2Fmegaparsec%29) of its current rate. Hooray for envelope backs!

  77. Michael T.

    Do all of those galaxies have a black hole at its center A few? most? Do we know or have any idea?

  78. tacitus

    Michael, astronomers are reasonably certain that those galaxies that are host to quasars have super-massive black holes at their center, and they have been seen as far as 13 billion light years away, so we know that some galaxies have black holes. I doubt there is any way to tell how many of those very distant galaxies that don’t have quasars have black holes, not directly anyway. The best bet is to study the evolution of galaxies and come up with better and better models for their formation from observations of closer galaxies.

    I believe most astronomers think that black holes are somehow either instrumental in the formation of galaxies or are the inevitable result, but they don’t know for sure which it is yet.

  79. Photon man

    I believe that those photons haven’t been traveling for even a second! Traveling at the speed of light, like they do, time stands still. From the photon’s point of view, no time went by at all. It’s Pop! you are created and Pop! you hit that detector. Mr. Einstein told me so.

  80. Michael T.

    @tacitus, thanks for the post. So is it too far afield to visualize the early universe as similar to a volumetric swiss cheese, where the cheese holes are black holes? I understand there is a chicken/egg issue with galaxy formation but if a black hole initiates a galaxy then at some point there was a perforation so to speak of space-time. Sorry if I am getting carried away with the cheese metaphor 😉

  81. Seamyst

    Tacitus and gibson042, thanks! Of course, now I remember that Phil covered that scenario in Death from the Skies!

  82. tacitus

    Michael, I may have misled you a little in my last comment. Astronomers don’t think that black holes formed before the galaxies formed. They are pretty sure that the pre-galactic era universe was clumpy (somehow) — some regions had more gas (and perhaps dark matter) then others — and, over time, gravity caused enough of the gas to accrete to form stars and then, eventually, galaxies. Once the galactic disks began to form then, at some point, there was enough mass at the center of the young galaxies for the super massive black holes to begin forming.

    What I should have said is that we’re not sure yet how involved the super massive black holes were in the evolution of newborn galaxies once they had formed at the center of those galaxies. Astronomers are still trying to figure out how much influence they had, once formed, on their host galaxy.

    Your picture of swiss cheese in the early universe isn’t actually that far off, but the holes would not black holes but just voids in space where there is little or no matter, and the cheese itself would be the dust and stars that slowly clumped together into galaxies and clusters of galaxies strung out over millions of light years.

    I hope that clarifies things a little :)

  83. nakomaru

    @OP “What you are seeing here is actually more energetic light emitted by galaxies that’s lost energy traveling across the expanding Universe, so by the time it gets here it’s infrared.”

    This should read “is actually higher frequency light.. that’s has been reduced in frequency”. The energy isn’t lost.

    @67 “The energy of the photon doesn’t change.

    Yes it does. Photon energy is *only* a function wavelength. Photon energy = h*c/λ

    @63 “Where does the energy previously possessed by the photons go?”

    This one I’m not as authoritative on. You are right that the wave energy (radiant energy) is not lost. It is not converted to matter. I don’t think the photons split into less energetic photons (as seen with scattering), but I may be wrong and I don’t think it matters. Here’s my take on it.

    If you have a single 1mm, high photon energy (& thus radiant flux) wave and you redshift it out to 1m, the photon energy has diminished 1000 fold as per E=h*c/λ, but now you also have 1000 times the wavelength.

    In this way, the radiant flux has been reduced, but the duration it takes the wave to pass the observer is increased 1000 fold (3.3 ps vs 3.3 ns). The total radiant energy of the wave is the integration of the radiant flux with time. I presume that the integration is the same for both of these waves.

  84. Star Counter

    Does this change the estimates of how many stars there are in the visible Universe? It looks like a 2003 survey made an estimate of 70 sextillion (7 * 10^22), but allowing that it could be much higher.

  85. If we don’t legislate Dark Sky practices – the Hubble will be the only proxy we have to see anything at night. Awesome image.

  86. You know, you’re going to have to start suing APOD for stealing “your” images.

    Once again, the day after you post an image like this, it appears on APOD.

  87. Ken B (87): Assuming you’re serious, that’s not really fair. Astronomers send out press releases with images like this, and so bloggers, newspapers, etc. get them and write them up. APOD gets a zillion submissions, and only posts one image per day, so is usually a day or so behind other bloggers – and I can’t react as quickly as say Universe Today, which has multiple writers! So it’s not stealing, it’s just different sites post them after the pictures are released.

    PLus, the guys at APOD are friends of mine, and we like each other’s work. :)

  88. Assuming you’re serious

    The one time I forget to put in the smiley… :-)

    But, you have to admit that tomorrow’s APOD is often today’s BAblog entry.

  89. Doug

    I’m proud to point out that I worked on the very first Hubble Deep Field nearly 15 years ago. I helped pick the field. My contribution was pointing out that it was far from the bright limb of the Earth and in the CVZ (Continuous Viewing Zone) so we could look at it for a LONG time and not worry as much about background light from the Earth. More have been done since with HST and others, and they just keep getting better.

  90. itskurtins

    You might also want to look for some gravitational lensing.

  91. paul

    This may seem like a silly question, which only occured to me last night.
    Given the level of detail the space telescope hubble can see, why are there no pictures of planets, moons, and other larger objects within these galaxies?
    It seems like somebody has missed the point along the way, surely the detail should be on the objects making up these clusters?

  92. Basta

    @79 Whoa! I didn’t even think to think of it like that, but now that I do it makes sense. To be frank, I don’t have my head wrapped totally around the special relativity thing (general relativity, more so, but still). I can get my head around this article, which makes me very happy as a quantum dilettante and somebody who never did great at math. I’m an English major. Maybe if I read up on the theory of this stuff and get to understand it better, I’ll be more inclined to try out the math again.

    And OP, why the “terrible scale” of the universe?! It’s wonderful! Really, you could go to inversely comparable powers of scale with subatomic particles and even things like the Planck length. The way I see it, we’re right in the center of all this, like a famous piece of art at the Louvre. That’s the best place to be, not only from a humanistic point of view, but from a scientific one too. If a galaxy could think, do you think it would be in a good position to contemplate itself AS WELL AS an atom? That’s hard to reconcile without our unique point of view.

  93. Jeremy

    Is there a written analysis of this image anywhere that actually explains what we see in this image? For instance, where does the info come from that leads BA to claim the little red dots come from 600 million years after the Big Bang (other than the fact that the hubblesite caption makes this claim)?

    I’m especially interested to learn how this image shows those tiny red dots to be ‘baby’ galaxies, and how those galaxies differ from the galaxies we see around us. Google isn’t helping me much with this one.

    Ooh, here’s a start:

  94. Tony

    To Joe Meils,

    I am not sure if others have answered your questions better, but a 1-sentence explanation goes like this: your assumption that the Big Bang occurred at one point is not right (just like there are tons of other misconceptions about the Big Bang, it is not a “Bang” after all). The Big Bang occurred *everywhere*. It created all space.

  95. DJGriz

    Can anyone further explain the 2d balloon expansion in 3d environment? I don’t quite get how you expand it to another dimension. Or link with info?? thanks

  96. dhvl

    If the Big Bang occurred to create space, where did it occur?

  97. Rob

    Big Bang happened everywhere.

  98. GWamp

    @Dave72 (#47) (and any others who took to his questions)
    This question always comes to mind when I see images of distant stars/galaxies. Not even in reference to are they still in that location (they’re obviously moving, so no), but do they even exist anymore?

    The light emitted from these objects takes SO LONG to reach us, could it be that by the time we are seeing these objects, that if we went to them in real-time (or instantaneously, if you will), to their current location, would they still be or would they have fizzled out? Are we still seeing them simply because the light took so long to reach us, but they actually no longer exist?

    At the time of this image, some of these objects were some 13 billion light years away or 475,000,000,000,000,000,000,000,000-4,750,000,000,000,000,000,000,000,000 (475 septillion-4.75 octillion) miles away (depending on if I was off a zero or not!) I don’t even know how long it would take light to travel that distance, and it may take a long time (if ever) for us to finally see them disappear, but…is this concept making any sense or is it just in my mind??? LoL I’m not a mathematician or astrophysicist by any stretch of the imagination. What math classes I passed in school, I did so with a “C”! I was even looking up the names to these numbers as I was typing this out, and it could be riddled with flaw.

    Just something to envoke some thought.


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