Astronomers find a galactic nursery 12.7 billion light years away

By Phil Plait | May 7, 2012 10:33 am

You know why astronomy is cool? Because of things like this:

Galaxy clusters are collections of galaxies held together by their own gravity. We see clusters all over the place, and they’re among the largest structures in the Universe. We can find them at large distances, which means we see them as they (and the Universe) were young — it takes light a long time to travel across the cosmos. Astronomers went looking to find extremely distant clusters of galaxies, and found one at a staggering distance: 12.7 billion light years away!

Here’s an image showing the central part of the cluster:

[Click to bigbangenate.]

Each of those circled red dots is a young galaxy, so distant that the light has been on its way here for more than 90% of the current age of the Universe! And they’re almost lost among all those other stars and galaxies in the image (though their intense red color helps… as to why they’re red, read on).

Finding this cluster was a magnificent achievement. The astronomers used the massive 8.2 meter Subaru telescope to look at large swaths of the sky. They looked at the colors of the galaxies they found (PDF); distant objects would be so far away their light is significantly redshifted by the expansion of the Universe itself (I explain how this works here and here).

Galaxies are distributed throughout space, so you expect to see them scattered across the sky as well as in redshift (distance). When looking at one part of the sky, however, they found an unusually high concentration of galaxies that were very red. Using a different camera on Subaru, they took spectra of those galaxies — breaking the light up into very fine divisions of colors, like a rainbow with hundreds of colors in it — to accurately measure the redshifts of those galaxies. Spectroscopy of objects that faint is no easy task, but Subaru is a big ‘scope, and collect a lot of light even from faint objects at the remote reaches of the Universe,

The astronomers confirmed that many of the galaxies in their sample were at the same redshift (z = 6 for those in the know — which is a mighty big redshift). The odds of these galaxies all being at the same distance happening by chance is extremely small: only about one in a billion! So it’s pretty clear these galaxies really are physically associated with each other.

That is, clustered together.

This makes the cluster the most distant ever found that has been confirmed spectroscopically — one other has been found that might be farther away, but it hasn’t been confirmed yet. At 12.7 billion light years away, that means we see this cluster as it was a mere one billion years after the Universe itself formed! That provides key information about conditions in the early Universe, which are critical to understanding how it formed and changed as it aged.

The cluster itself is vast — it’s something like 50 million light years across. The team of astronomers used various methods to determine its mass, and their best guess is that its total mass is several thousand times the mass of our entire Milky Way galaxy! The estimation methods they used are fairly fuzzy, so it’s not clear how accurate this number really is. Still, the cluster is clearly huge, and massive. If we could see it today, it would probably rank among the largest structures in the Universe.

That’s not terribly surprising, if you think about it: only the biggest monster clusters can be seen at such a mind-crushing distance. The smaller ones will be harder to detect, so we’re likely to find the biggest.

Still, holy cow. I have read and written about extremely distant objects many, many times over the years, and have no doubt: I get chills every single time I think about this stuff. It wasn’t that long ago when the entire human race couldn’t be bothered to look beyond the tip of its collective nose. Now we can look into the fires of the Universe’s birth, into that forge itself, and tease out the secrets of how we came to be.

That’s why astronomy is cool.

Related Posts:

- An ultradeep image that’s *full* of galaxies!
- Most distant object ever seen… maybe
- Another record breaker: ultra-deep image reveals ultra-distant galaxy
- Record-breaking galaxy found at the edge of the Universe

Comments (34)

  1. Florian

    Yes. Thank you. I share your sense for neverending wonderment. Data like this always makes me ask how galaxies could form so fast after BB. Matter seems to like being structured. Are there convincing working theories on galaxy formation in the early universe? Does anyone know where the inhomogenities came from?

  2. Bjoern

    12.7 billion light years *away*? Err, no. The *light travel time* was 12.7 billion years – that does not mean that the *distance* is 12.7 billion light years!

  3. Marvellously mind-boggling discovery that. :-)

    Co-incidentally the word Subaru = the Plieades, Seven Sisters, Messier 45 in Japanese. Apt.* ;-)

    Galaxy cluster, star cluster, same diff! (well yeah, I know, *not* exactly. )

    I love that poetic last paragraph there. Superluminously well said. 8)


    * If people look closely at the eponymous car company badge they’ll see those seven stars, the mythical Alcyone, Merope, Taygete, Maia, Celaeno, Electra, Atlas & Pleione, those far distant blue-white hot multiple times larger than our Sun spheres of searing plasma shining across the hundreds of light years as one of the night’s great wonders.

  4. Thank you, as always an awesome blog.
    I’m gonna be the annoying guy coming in with a technical correction that totally doesn’t have anything to do with the awesomeness of the topic ;-)

    You write : “At 12.7 billion light years away, that means we see this cluster as it was a mere one billion years after the Universe itself formed!”

    This is only true in a static, non-expanding Universe, just like the size of the observable Universe is far larger than the 13.7 billion light years one would expect. The proper distance – that is, the actual distance today as we would measure it with a ruler big enough – to an object with a redshift of exactly 6 (that is close enough, that would mean the light was 12.4 billion years old), is around 27 billion light years – more than twice the distance of the 12.7 billion years mentioned.

    If, on the other hand, the Universe were static, the light would have reached us much faster (because the path it travels is being stretched during the travel) than it actually has – so the proper distance to these galaxies at the time when the light was emitted, was quite a bit *smaller* than the one inferred from the time it has travelled.

  5. KaneHau

    Aloha from Subaru Observatory…

    Thank you Phil, for posting this!

    Mahalo nui loa!

    (P.S. to Messier Tidy Upper – just to clarify to others, Subaru Telescope is not affiliated with the car company bearing a similar name)

  6. gameshowhost

    0.5 arcmin at that distance? wow

  7. Jon Gluvna


    meaning our year is not equal to a UNIVERSE YEAR
    is any of this getting thru.

    stupid scientists.

  8. This_Guy

    Mind-crushing does not even begin to describe the distance! We need a new word, or combination of words to ACCURATELY describe that overwhelming distance. I nominate “ZOMGWTFBBQ”

  9. Ha. In “Who Got Einstein’s Office?”, a book about the Institute for Advanced Study in Princeton, one of the inside jokes for the astronomers/astrophysicists at the institute was the discovery of a galaxy with a redshift of z=6. This was back in the 70s and 80s of course. It’s funny how that has come true now.

  10. I am sorry, my comment above was of course meant to address the statement that light that traveled 12.7 billion years comes from a source that is 12.7 billion years away. Also, I see that the error stems from the press release from the group itself.

    Also, my latest statement was of course wrong – if the universe was static, the light would travel 12.7 billion light years in exactly 12.7 billion years. What I meant to say was that these specific galaxies were closer than 12.7 billion light years at the time of emission, but this region was receding from us faster than the speed of light (this is in fact true for any object with a redshift larger than around 1.8) due to cosmic expansion, so these photons were in fact receding from the Milky Way at the earliest times and only later started moving closer to us.

    For a more thorough treatment of cosmological distance and “faster-than-light” expansion, one can take a look at this great paper by Tamara Davis and Charles Lineweaver: .

  11. Chris

    You know you are an astronomer when someone says Subaru and you immediately think of the telescope. :D

  12. jayscheuerle

    Unfortunately, Subaru (the car co.’s) badge only contains six stars!

    The six sisters?

  13. Alph

    help me out here…..if those galaxies are within a billion years of the Big Bang, then is it fair to say that the Big Bang happened in the direction of those galaxies? And if we were to turn the telescope 180 degrees and look in the opposite direction, we’d be looking toward the ‘edge’ of the Universe?

  14. @Alph;

    Big Bang happened everywhere at once.
    No matter in which direction we look, we look back in time, so the farther we look, the farther back in time we look. Closer to Big Bang in a time-like sense, but not in a “geographical” sense. Big Bang was the entire (and probably infinite) Universe expanding at once at explosive speed.

    The interesting question is then, “expanding into what”?
    The answer is a bit tricky; I usually compare it to a coordinate system that you draw on paper. We accept that the axes reach infinitely in all directions (even though we only draw a small piece of them).
    If we now draw a second coordinate system, but with twice as far between the numbers on the axes as before, we have “expanded” the coordinate system, even though it was already infinite. Something very similar is probably the case with the expansion of the Universe.

  15. Wes

    Alph, I’m not an astrophysicist or astronomer, but I believe one of the weird things about the big bang and its aftermath is that EVERYTHING is moving away from EVERYTHING ELSE. Can someone refresh my memory about this – my ASTR101 class was like 20 years ago. Something about the universe is not a line or a ball but somehow twisted and folded upon itself as everything expands.

  16. Herman

    The Big Bang didn’t happen in any direction or spot because space itself is expanding everywhere at the same rate ever since the event. So there is no center. There could be an edge but because space is expanding faster than the speed of light we will never reach it. That’s why astronomy concerns itself only with that part of the universe from which light was able to reach us since the Big Bang, called the observable universe. The galaxies in the photo are pretty close near the edge or ‘particle horizon’ of that spherical part of the universe.

  17. Worlebird

    @Alph #6 No, you actually can’t say that the Big Bang happened in any particular direction. You may have heard of the analogy of the balloon. The expanding universe is like a balloon – as it grows, all the spots on the surface of the balloon (galaxies) move away from each other. However, can you point to a spot on the balloon that is the center of the expansion? A place where the initial blow into the balloon happened? Not at all. Everything is expanding from everything else, and everything can be said to be at the “center” of the expansion from its own point of view. When the Big Bang happened, everything was in one place, and there was no other place to be. So there is no spot in the universe where the Big Bang happened – rather, all spots in the universe are where the Big Bang happened.

  18. KaneHau

    Alph #6…

    There is no center and no edge to the universe. There is an observational sphere that is centered on every point in the universe (that is… every point in the universe can be considered as the center from that points perspective).

    What we see when we look out 13 billion light years – in any direction – is the horizon of our observational sphere.

    If you move one foot to your right, your observational sphere also moved one foot to your right, etc.

  19. Ori Vandewalle

    Alph: What Worlebird said. Also, if you do point your telescopes 180 degrees and look in the opposite direction, you see (more or less) the exact same thing. One of the principles of modern cosmology is that the universe is isotropic, which means that it looks the same in all directions.

  20. But there are things we can’t see anymore, because expansion and time has put them out of range. Thus the most distant things you might have been able to see when this galaxy cluster first shone the light we’re now seeing are long off the map as far as we’re concerned, at least in certain directions. Which brings me to the question, how big was the universe when this light first emerged?

  21. Brian Too

    What strikes me about this image. It is so busy, with so many light sources, I’d guess that some of the galaxies in that cluster are certainly behind other, closer objects. Also, if it is as big as the B.A. says, that would only increase the odds of this happening, no?

  22. FMCH

    Sorry, as a Young Universe Creationist, I believe that the universe is only 6 billion years old. Anything else is a liberal conspiracy designed to lead the world to ruin.

  23. Liath

    It seems this is a day to get questions answered. And answered clearly which is a huge relief to old geezers like me. So… my question is: Because we are all moving away from each other an these incredible speeds, how come galaxies collide. Is it all gravity that is strong enough to overcome inertia? Andromada is not exactly next door to the Milky Way and yet the forecast is that we will have a great meetup in the realitively distant future. Young whippersnappers tell me that gravity is the weakest force and yet it appears that gravity is strong enough to pull together two huge galaxies at great distance. Is this correct?

    The next question is: what will be the new trajectories of the galaxies after they have merged and then seperated. Is there any way to determine that? Or is that a meaningless question?

  24. John

    Yes, gravity is by far the weakest of the known forces — 100,000,000,000,000,000,000,000,000,000,000,000 times weaker than the electromagnetic force. (It took the entire mass of the earth to break the electromagnetic force between molecules in the stem of Newton’s apple.) HOWEVER, electromagnetism comes in both positive and negative varieties, and they normally cancel out. There is no anti-gravity, so it is purely additive, and if the mass gets large enough, it can overpower everything else. (It takes a mass the size of the sun to condense something to a white dwarf, and maybe four times that much to crush those atoms out of existence and form a neutron star.) So yes, the gravitational attraction between the Milky Way and Andromeda has a much larger effect than the expansion of the fabric of space between them. On the scale of the entire universe, the two galaxies are microscopically close together — two million light years apart IIRC compared to twelve BILLION.

    (Galaxies are quite close to each other relative to their sizes, compared to the spacing of stars. If a galaxy was the size of a quarter, the next galaxy would be only a foot or so away. If a star was the size of a quarter, the next star system would be hundreds of miles away — about one per state.)

  25. Messier Tidy Upper

    @5. KaneHau :

    (P.S. to Messier Tidy Upper – just to clarify to others, Subaru Telescope is not affiliated with the car company bearing a similar name.)

    Ooops, yes. Sorry that wasn’t supposed to be product placement at all just an observation.

    @12. jayscheuerle Says:

    Unfortunately, Subaru (the car co.’s) badge only contains six stars! The six sisters?

    Most people can only see six stars, it takes very good eyesight to see more. Try counting them next time you see the Plieades and see.

  26. @ ^ BTW. There’s some suggestion that one of the “seven sisters” stars may have faded and become less easily visible in historic times. Pleione a Be type – for emission – “shell star” is, I’m fairly sure, one candidate for the “missing Pleiad. Although looking at its entry on Kaler’s site (linked to my name here.) apparently it switches from normal to Be star in a repeating cycle.

    Kaler suggests that the misisng Pleiad is instead Celaeno which is one of the fainter of them although Sterope – is very faintest named “sister” and could also be the Lost Pleiad which, Greek legend has it, hid in shame because she married a mortal whereas the others married gods or something. Another version has it Pleione as the mortal mother of the other eight named Pleiads with Atlas their father being the Titan who holds up the world. :-)

    I think I recall reading of Patrick Moroe doing an informal experiment once to see how many M45 stars people could see unaided eye – the average being six.

  27. hdhondt

    @Liath, from one old geezer to another

    Galaxies that are “close” to each other, as they are in a cluster, do not move away from each other. The gravitation within the cluster keeps them together, and as they travel around the centre of mass of the cluster, they can bump into each other.

    Computer simulations have been done on galactic collisions, and some can easily be found on the web. In fact, Phil posted one a couple of years ago: . As to exactly what will happen when we collide with Andromeda. I think there are far too many unknown variables to give even an approximate answer.

    Gravity is indeed the weakest force, but it’s also the only one that is always attractive. Electric charge, for example, comes in two flavours which we call positive and negative. In any object there are almost exactly as many positive as negative charges, so the total charge is zero. With gravity that does not happen, more mass always adds to the attraction.

    If Dark Energy rules the universe in the distant future, this may change: there may come a time when gravity is no longer strong enough to keep clusters together. Even further into the future, Dark Energy may rip galaxies apart, then stars, and eventually even atoms.

    I can’t wait to see what will happen after that…

  28. Messier Tidy Upper

    I think I recall reading of Patrick Moroe [D'oh! Typos! - ed.] Moore doing an informal experiment once to see how many M45 stars people could see unaided eye – the average being six.

    Aha! Found it & found I’ve misremembered :

    “How many of the Pleiades can you see with the naked eye? I once carried out an experiment, enlisting the help of viewers of my television programme The Sky At Night and found that the average number was indeed seven, though some people could see more. The record is reputedly held by a nineteenth century astronomer named Eduard Heis, who could count nineteen.”
    – Page 156 ‘Patrick Moore’s Passion for Astronomy’, P. Moore, Brunel House, 1993.

    So my apologies. I got it wrong and most people *can* after all see seven stars in Messier 45.

    Although I wonder when that experiment of Moore’s was conducted and how much light pollution has increased since.

  29. Today. Astronomers find a cluster of galaxies 12.7 *billion* light years away. Tomorrow. Young earth creationists say that “The data is flawed, misinterpreted, false or there’s something else wrong with it because it does not verify our wishful thinking.”

    /believes there is a God that created everything, but is not blind to scientific fact

  30. Liath

    Thank you John

  31. Brad

    Does anyone know about how many photons are collected from such a galaxy to make an image like this one?

  32. When the James Webb goes up I expect our vista to be full of such clusters that will seem to be farther apart than our neighborhood clusters. My expectation is that this same kind of observation, but in finer detail, will have some galaxies appearing to be as old or older than the Milky Way. Maybe at that time they will finally start to realize that the Big Bang is the wrong cosmological model. But first I expect there will be a number of valiant attempts to greatly increase the age of the universe according to the Big Bang model.

    After a few years, however, maybe by about 2020-25, I expect they will be considering alternative cosmological models that would allow for a much older universe. Maybe ten years after that the BB may no longer be the prevailing model in cosmology because of observations like this one, but in much finer detail. This is my prediction. The distant universe is the same as the local universe even though is some ways it presently appears to be different.

  33. Tribeca Mike

    Silver beetles in front of the camera lens perhaps, or is that Lennon-McCartney reference too obscure or irrelevant?

  34. conincalgary

    12 billion years ago, wouldn’t everything have been much closer together?


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