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101 Giant Galaxy Clusters Discovered
Porfiry says: "Astronomers behind the Massive Cluster Survey (MACS) have uncovered 101 giant galaxy clusters, many of them so distant and thus forming so early in the history of time that they challenge our current understanding of how quickly the Universe evolved into its current hierarchical structure of stars, galaxies and clusters. Galaxy clusters are the largest gravitationally bound structures in the Universe, typically containing a few hundred to thousands of galaxies, each of which in turn contains many billions of stars."
"HOLY Great Gargantuan Galaxy Clusters, Batman!"
or something like that....
Contrary to popular belief, I don't actually make my website for other people to look at.
Er, no. A neutron star has a diameter of about 10 kilometers.
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...that the universe is actually both infinite and constantly expanding, with little bangs producing universlets in any sufficiently empty space. The speed of light is an absolute limit for matter, energy, or information and so for any two sufficiently distant points, you will never see one from the other (or, of course, be able to reach it), with areas not bound by gravity moving apart from each other to become lost to each other forever (which is why the sky isn't dazzlingly bright at night from all the infinitely-old galaxies).
It explains why our local universe is young, without positing anything so absurd as a time before time or a limit to the space out there (if there's 3-dimensions, there has to be a wall, if there's 4-dimensions, what happens if you take a step "sideways"? again, there has to be either infinity or a wall, beyond which there has to be less than nothing; adding dimensions is just hand-waving, adding complexity until you come up with a model beyond your capacity to criticize).
The moral? Exploit away! Strip mine planets and eat stars for fuel. There's plenty more where that came from, and if you expand out in all directions simultaneously at nearly the speed of light, nothing can ever catch you and your species will last forever in the ever-expanding shell. Sit in a bounded area and eventually someone tougher and with a better survival instinct will evolve in the baby universe next door and come to wipe you out (or the stars will just burn out and you'll die because you were too lazy to go get some fresh stars).
We're in the infancy of our corner of the universe, and it's only going to get more interesting from here on out. Think of it, always something new, no end to the adventures on new worlds, a physical universe as infinite as mathematics. Get your immortality pill and hop a ride on a hydrogen scoop A.S.A.P.
O what a generous god who made our universe without end!
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Can't it be possible that the light travels in a cirkle?
Possible, but unlikely. I've ridden in a cirkle once, and it was terribly uncomfortable.
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...of the food chain. So I like to eat cannibals, preferably those who prefer cannibals. Lately I've been snacking on the less vital portions of my limbs.
I would never bother with vegans, they are lower on the chain than decay bacteria.
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lets see. no, the light waves wouldn't cross each others path. Most electromagnetic radiation leaves it source it expands at the rate of the distance divided by time squared[don't have a book handy to confirm, but it think that is it]. The reason stars and the such appear as points of light is simply because they are so far away.
Yes, but it could be seen as a single atom nucleus. After all, it contains mostly neutrons, and you need quantum mechanics to study it.
"About two years from now--if MAP survives the simulator, the launch, and a three-month journey into space--humankind is likely to finally find out how old the universe really is; how it will come to an end; whether space is really infinite; and most astonishing of all, what shape the universe takes."
"What appears to be a distant galaxy might actually be light from a very young version of the Milky Way that has made a 13-billion-year complete circuit around a finite universe. Instead of holding billions of different galaxies, the universe might hold mostly mirages, repeated images of a far smaller number of galaxies. The images would be the result of light taking different pathways through the cosmos at different points in a galaxy's history."
Pretty interesting article that explains some of the objectives in an easy to understand manner.
No, basically, they're orbiting each other, just not in neat orbits.
I hate when someone says "basically" and then says something that one in a hundred people will understand. People understand the idea of orbiting a lot better than the physics underlying it.
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If something is moving away from us at nearly the speed of light (say .9c), then the light from that object still moves towards us at c, rather than .1c as you might expect.
Still, I agree that it is funny how people always assume that the observed limit of the known universe is the actual limit of the universe
This result doesn't change my understanding of the universe at all - I don't pretend to have one - unlike many cosmologists.
It's funny how little cosmologists confidence in already knowing everything (like age & size of universe) was shaken by the fact that their most fundamental prediction of the behaviour of the universe was completely wrong. (The fact that distance galaxies are accelerating away from us as opposed to decelarating)
http://rareformnewmedia.com/
The universe is the largest gravitationally bound structure in the universe...
,whatever that means in curved 4d Riemann space. If it did, our universe model would be incorrect (which is conceivable but not observed) but remember that both gravitational lensing and our cosmology are derived from the same set of equations: general relativity. Using one to disprove/change the other is impossible.
Recent distant supernova measurements indicate that the expansion of the universe is accelerating in recent epochs: thus the universe is not gravitationally bound.
but it is feasible that as these distant structures are studied in more detail gravitational effects which indicate some other very large masses outside the bounds of what we can detect as the edge of our universe are discovered.
Interesting idea but some major problems. Outside the bounds of our observable Universe, would mean way back in time when the universe was so hot that ionized gas made it opague (because we look back in time). I cannot mean spatially 'outside'
Furthermore lensing signal is only detectable against background sources in specific configurations, because they are the ones that are distorted. If you go to really high-z you're are rapidly running out of sources, apart from the fact that they are incredibly faint and small. (ie better test this in the nearby universe: since the responsible mass is 'outside' our universe there is no need to go distant). Besides this, there's an argument against large mass concentrations influencing our Universe, the gravitational shear this would introduce would be VERY observable as the first superstructures were forming, biased by the influence of this mysterious matter. But the universe is amazingly smooth at large scales. (btw if the gravitational waves from the 'other universe' can travel to us, why not matter and electro-magenetic radiation)
For all you cosmo-zealots: the 'edge' of our detectable universe is one in time not in space. It is called the Cosmic Microwave Background, and it's a wall of plasma redshift by about 1500 to the microwave regime. You see it in every direction you look, we are surrounded by it.
Euclidian style thinking wont get you very far in cosmology.
We are all in the gutter, but some of us are looking at the stars
Nobody I know hates Halton Arp. Most people in the astronomical community have a great deal of respect for him and his work.
However, the evidence that supports his interpretation of redshifts is, quite frankly, weak. Most, if not all, of his "showstopper" examples are quite possibly a consequence of a selection effect, nothing more. And the whole idea of "tired light" has no basis in any physics that we currently know about. In other words, some very big discoveries, would need to be made and a couple of Nobel prizes would have to be given out before most astronomers would accept Arp's interpretation. Current evidence just doesn't point in that direction.
And his theories are definitely not a linux thing any more than any other endeavor that requires a high degree of precision, a whole a lot of sweat, and a great deal of ability to solve nearly intractable problems. The similarity ends there, no matter how much you want to root for an "underdog."
Shop Smart, Shop S-mart!
Ugh! I really think it's time we get MathML working. Trying to parse carrots and underscores is getting increasingly irritating. :)
Shop Smart, Shop S-mart!
If something is moving away from us at nearly the speed of light (say .9c), then the light from that object still moves towards us at c, rather than .1c as you might expect.
...unless it is space itself that expands faster than c. '> c expansion' occured in the inflationary period in the beginning of the universe. Observational 'prove' is the homogeneity of causally disconnected areas in the cosmic microwave background and the overal homogeneity of the observed universe. Only an inflationary 'faster than light' expansion explains this feature in a natural way.
It's funny how little cosmologists confidence in already knowing everything (like age & size of universe) was shaken by the fact that their most fundamental prediction of the behaviour of the universe was completely wrong. (The fact that distance galaxies are accelerating away from us as opposed to decelarating)
Actually, supernovae results indicate that the universe switched to acceleration only in recent epochs z=1. De/accelaration is notoriously hard to measure at some distance and no cosmologist would have claimed now or in the past that testing universe models is a precision job. De/Accelaration in itself not a fundamental prediction, it is a measurement then to be used to justify different models. And there are a lot of tricky stuff involved with supernova measurements. Oh, and last but not least. SNe do not provide any clues at really high redshifts z>2.
We are all in the gutter, but some of us are looking at the stars
Galaxies in a large cluster do tend to collide with each other more often than those in a small group or "free" unbound galaxies. Spiral galaxies like ours get progressively more rare as the groups become larger. Usually though, the galaxies just pass right through each other and come out the other sides. Spirals involved in collisions tend to become elliptical galaxies as they finish. Galaxies only tend to absorb other galaxies when the relative encounter speed is low enough.
Clusters eventually tend to be dominated by a single large galaxy like the giant elliptical M81 which the rest tend to loosely orbit.
As a footnote, it's all but confirmed that the Milky Way Galaxy and Andromeda are in a collison course. We should start seeing the effects in a few million years. Someone's modeled the upcoming collison, unfortunately I forget who.
note lack of "B" word...
Why is it, that with almost every science topic people make redundant jokes and/ or simply make a completely offtopic remark? (this is not directly aimed to the post I'm replying to, more a thing I've noticed in general)
---- Stage 5 of drinking : Politics begin to appeal
The falling of matter from an accretion disk is enough to put out a lot of X-ray. Provided that your gravitational field is strong enough, it's a very efficient way of converting matter into enery (more than fusion, btw).
is that we are looking at our own light. Can't it be possible that the light travels in a cirkle?
You start your post by claiming that your theory has been "proven" (the only thing you've proved is your ignorance of the way science works). You continue by pontificating self-congratulatingly and without meaning. And you end it thanking God for it. Why the hell would I take you seriously?
If DullBlade's post is a troll, it isn't a particularly good one. If it's a serious post, it's quite stupid.
To the editors: your English is as bad as your Perl. Please go back to grade school.
That's a stupid philosophy. Every link on the food chain means a tremendous loss of energy; just by living, a cow wastes most of the energy stored in the sugar reserves of the plants it eats, a man wastes most of the energy stored in the fat cells of the bovine meat he eats (and he also breaks all the cow's proteins into aminoacids only to assemble them again into proteins, spending even more energy), and a cannibal does the same thing to the men it eats. So let's draw up an energy consumption table for this food chain (with an arbitrary unit of energy):
Being Source [1] Wastes [2] Passes on
Plant Sun (100u) 99% 1u
Cow 10^6 plants 99% 10^4u
Man eq. 1 cow 99% 100u
Cannibal eq. 10 men 99% 10u
Cannibal^2 eq. 10 can. 99% 1u
_YOU_ eq. 10 can. 99% _0.1u_
[1] Throughout the being's lifetime.
[2] Just a guess; I don't have the actual values
See, smart-ass? Cannibalism doesn't pay off...
To the editors: your English is as bad as your Perl. Please go back to grade school.
Surely then he realises that both beeves and broccoli are merely the carcassas of dead supernovae
hey beeves, you said carc-ass.
shut up broccoli.
Arm yourself with knowledge.
While light from an object travels to us at c no matter how fast the object is receding from us, eventually as the speed increases the light is red shifted so far down it becomes unobservable when the object's recession speed equals or exceeds c. Thus is defined the "observable universe". In practical terms it'll be somewhat less as our instruments for observation will always be a bit short of the thorectical ideal.
The universe is the largest gravitationally bound structure in the universe, since sets can include themselves... But, really, I digress ;-)
:-)
Or, do I. The possibility exists that what we observe as our detectable universe is a gravitationally bound structure which is immersed in a large collection of similar structres. Currently, this would be pure speculation, but it is feasible that as these distant structures are studied in more detail gravitational effects which indicate some other very large masses outside the bounds of what we can detect as the edge of our universe are discovered. This could, of course, just mean that more large galaxy clusters lurk outside our range of detection, or it could be that an effect sufficiently severe be discovered that it appears that maybe another extremely large gravitationally bound cluster - one we might wish to call another "universe" - existed.
Right now, of course, this is all just speculation... but it's fun speculation
o/~ we are pissed, we are pissed, we have to resist... o/~ - ec8or
I thought the "big bang theory" said that all matter was concentrated into a single point. If thats true then there wern't any galaxyies around to be 'closer' then any others.
Cosmic expansion is a bit more complicated and like it's been said , you have to divorce yourself a bit from Euclidean gemometry. It's notjust the universe that expands but space itself. The Big Bang is not an event that happened at a particurlarl point in space, it's more accurate to thing of the Big Bang as an event that happened everywhere at once.
Also check out the concept of "inflation" if you get a chance.
are the largest gravitationally bound structures in the Universe, typically containing a few hundred to thousands of galaxies, each of which in turn contains many billions of stars.
That's gonna be one really huge (or really small) black hole one day.
BTW, if it turns out there is enough matter, wouldn't the universe be the largest gravitationally bound structure in the Universe?
IIRC, there are only two galaxies (excluding ours) visible to the naked eye, Andromeda, and the Magellenic clouds. Everything else you see with your naked eye is a star.
Atoms are so small you can't see them with the naked eye.
Galaxy clusters are so large, and so distant that you can't see them with the naked eye.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
X-ray cluster science has been a bit slow about accepting Omega_matter = 1. I still see papers with Omega_matter = 1 and the hubble constant at 50 km/s/Mpc.
What is interesting about the MACS survey is that they will find the most massive systems at z~0.3. Optical selection has some serious problems, X-ray selection has different problems but at least, unlike optical selection, you will not be stuck with a large amount of flotsam and jetsam in your sample. And, the most massive systems are the ones that are suppose to have the most constraining power if you believe the semi-analytical results.
I do agree, however, that RASS results are not all that interesting, at least in a /. sense.
Of galaxies may be quicker than originaly thought. They did expect to find galaxies that old. Well maybe when the "big bang" happen since these galaxies where closer to the bang they form quicker than galaxies that were further away from the bang. Also it is late at night and I do not have a clue what I am talking about so how knows.
Oprah Winfrey, who was, for a time, the largest gravitationally bound structure on Earth.
-cibrPLUR
so i thing mr. hawking has to correct his nice litte book now...
what i do wonder is that the galaxies in a cluster do not collidate all in the middle of it because of their great mass. i suppose it's because of the space between single galaxies in a cluster are just too big or so.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
Dark matter frosted clusters of galaxies. Snap crackle pop big bang when you add the milky way
Even the cosmos is gettin
in on the beowulf craze...
I gotta get me one of these
101 node/galaxy clusters
.sig wanted: Must be concise, funny, and display my cleverness.
And that would've been great publicity for Apple in the scientific community!
Development of galaxies may be quicker than originaly thought. It certainly is, if that Arp astronomer that everyone loves to hate is even partially right. He has Quasars being baby galaxies, fired off from other galaxies... maybe, maybe not, but his re-interpretation of redshift (with extensive documentation and numerous showstopper examples) is certainly interesting, and is very much a Linux ``it can't be done, but that hasn't stopped it from happening'' paradigm-busting phenomenon.
Got time? Spend some of it coding or testing
So it's safe to say there's "billions and billions of stars" ??
I want to delete my account but Slashdot doesn't allow it.
I am a committed carnivore
Oh, they have Internet in the asylums these days? (-:
Seriously, if you were a committed carnivore, you would be committed to hospital within about two weeks unless you chose mostly fish and other relatively low-fat low-pollutant meats and ate them all raw and were happy with a lifespan of under 40 years. This has been tried before, several times.
Oddly enough, two weeks is about how long people last on an all-MacDonalds' diet as well. Perhaps that's the typical amount of time can survive on recycled garbage before it tosses in the towel.
I prefer my food first-hand... (-:
Got time? Spend some of it coding or testing
strikes me that we could be watching our own galaxy develop. how strange is that?!
Prove that this doesn't prove my theory.
Incidentally, it was neither a troll nor serious.
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[RANT] I become increasingly frustrated with the way science (especially astronomy) is portrayed on /. Although I'm happy that ppl take interest in this field, I feel that creating hypes or suggesting breakthroughs in every little article is just not the way to go. It may be the american way... I dunno. For NASA, pumped PR is essential for its survival. I'm also amazed that whereas /. readers are in general critical and sceptical, when the subjects changes to science they believe everything without actually trying to understand what is being said.[/RANT]
Finding clusters @ z = 0.3 is no big deal and wont challenge our current understanding of how quickly the Universe evolved into its current hierarchical structure of stars, galaxies and clusters. The current theoretical (numerical) view of the deep universe comes from the Virgo Consortium and predicts the existence of clusters on much higher redshifts. Wat is interesting is that it appears to be relatively easy to image large amounts of cluster. Clusters have been found out to a redshift of 1.2 (universe 40% of current age) and protoclusters at z = 2.2 (universe 25% of current age). CAVEAT: this MACS sample are selected on basis of their X-RAY properties; they were snatched from the ROSAT source list. Only heavy clusters with lots of infalling gas will produce much X-RAY emission, therefore biasing against smaller/less gass rich clusters. It is completely unclear if the study of high density regions (ie clusters) is representative of global picture galaxy and cluster evolution.
There is also a program underway called the Sloan Digital Sky Survey; a huge project where they (amongst other things) try to find clusters by optical selection in an automated way.
Finally, the article states "The analysis is not yet complete, but it is already clear that our observations are in conflict with a high value of omega."
Translation: this does not mean that our current picture is challenged. To the contrary: this study very crudely confirms other analysis (spatial structure in cosmic microwave background) and arguments for low omega_matter. Low Omega_matter is the currently favoured model. Trying to present this study as a breakthrough in this respect is false.
We are all in the gutter, but some of us are looking at the stars
I know that this is the best we can do with our "remote sensing" of the stars, but what if our models are wrong and we should be thinking differently. (Or maybe it is just that the universe is more complex than we have previously imagined.)
I would just like to note there are a number of cluster surveys going on out there. Including one, called the REFLEX survey, that uses the same data, the ROSAT All Sky Survey, as the MACS survey as a starting point.
What makes cluster surveys interesting is not just the scientific output but the various means of finding clusters people are trying. For example, the MACS survey mentioned above uses a Voronoi tesselation of the original X-ray data to detect and find sources. Other surveys use wavelet techniques, such as the SHARC survey (to pick one out of the air) or adaptive kernel smoothing, such as the Northern Sky Optical Cluster Survey.
Is it a bit odd to see what I do for a living on /.
The ramifications of this study and the study that my group is doing is challanging what we understand of Gravitational Theory, Age of the Universe Theory, and current red-shift theory, since all of these models come short of explaining the observations that we, and this article are gathering.
What we are finding are galactic clusters that are so large, that there is not enough time in the age-of-the-universe model to form. So either the Universe is SUPER old, or our concept of gravitational theory is incorrect. (Currently the age of the Universe is slated between 13-18 billion years, and these objects are so huge that 18 billion years is a drop in the bucket in the ammount of time required.)
So this is the quandry and now this study has found MORE of them.
Some astronomers have tried to explain these descrpencies with Dark Matter, but I'm skeptical.
And this is just Carlosian opinion, and should be taken as such.
*Carlos: Exit Stage Right*
"Geeks, Where would you be without them?"
*Carlos: Exit Stage Right*
"Geeks, Where would you be without them?"
"Got Linux?"
BTW -- and I could be remember things incorrectly here, but I don't think so -- the issue of dark-matter bias (how well the visible matter traces the dark matter) doesn't really affect these particular results too much, at least as long as you assume the bias isn't changing dramatically over time. (And as long as you take whatever bias you pick as a prior for all possible values of Omega, as opposed to mushing it around as you see fit.) You're right that there's degeneracy, but I think most of that comes from the lambda, Omega business, and the distributions of clusters expected are not totally indistinguishable, just close.
Clusters of galaxies are not so large that there is not enough time in the universe to form them. There are two pieces of evidence for this.
One piece is that clusters of galaxies are only 1.5 Megaparsecs in size (or about 5 million light years). The universe is 15 billion years old, so over the course of the history of the universe your average galaxy go back and forth across a cluster about 10 or so times at the speeds galaxies whiz about at in clusters. And don't forget, according to the standard model, the universe was a lot smaller back in time, so clusters were not as big.
Secondly, we are watching clusters form as we find higher redshift clusters. Clusters at redshifts of z~1 look a lot more like amorphous blobs then low redshift clusters (which look more like circular blobs). Quantify that and you have nice paper in ApJ.
I suspect you are talking about super clusters and the like. It is not clear that you need to toss out everything we know yet because of super clusters. First off, they are not bound by gravity, so they could be very young. Secondly, as I said before, the universe was a lot smaller many billions of years ago, so it takes less work to form them early. And, of course, any theorist would respond with one word and one word only, inflation. Fortunately, I am not a theorist.
I am a committed carnivore. I prefer to eat committed vegetarians.
134340: I am not a number. I am a free planet!
> Not only is Harold Ebeling a professional astronomer, he's a committed vegetarian.
Surely then he realises that both beeves and broccoli are merely the carcassas of dead supernovae?
Sheesh, evil *and* a jerk. -- Jade
I thought they were just fans of Apple computers?
Any sufficiently advanced civilization is indistinguishable from Gods.
This is very interesting. Of course the popular article is short on details. Of interest to us astrophysicists is how many, how massive, and how large z, and how large a volume did they survey. We already know of a few clusters nearly 10^5 M_sol at z=0.5-0.8. I'll have to ask for details once they get back from the HEAD meeting...
But, in any case, the claim of hundreds is very exciting. In a universe with a large \Omega (both matter and dark matter, but not lambda or quintesence), massive clusters become extremely rare at large redshifts. That's why the person claims this will help measure omega very accurately. Unfortunately, there is a degeneracey (I believe the primary degeneracey is how much the luminous matter distribution is representative of the dark matter distributions, but I'd have to check to be sure.) and this observation alone can not determine Omega. However, when combined with other observations (such as supernovae and CMB), Omega can indeed be tightly constrained. We're closing in...
...a Galaxy cluster of these things!
I'm a theoretical chemist. I spend my time studying things on a scale of several atoms. I also enjoy quantum physics which deals with smaller stuff, so these atoms seem humungous. Now I step back and look at the stuff the organic chemists are doing, and wonder at the size of the molecules in amazement. But that's really nothing compaired to the biochemists and thier macromolecules. Then there are the structural engineers who deal with unimmagniable amounts of stuff; where the sheer number of atoms involved is unifathomable. But the geographers deal with masses; contenents; worlds! of this stuff. Then I look up at the sky and see white dots, some of which are galexy clusters containing thousands of galexies. And I fall down on the ground dizzy...
Sometimes I've believed as many as six impossible things before breakfast.
Take neutron stars, for example: entire solar masses compressed into a single neutron nucleus. See? It's still on an atomic scale.
-- Anne Marie