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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."
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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...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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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
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.
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
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.
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.
[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
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.
I am a committed carnivore. I prefer to eat committed vegetarians.
134340: I am not a number. I am a free planet!
Angular momentum creates a barrier in terms of the effective potential. Basically, unless the material can find a way to dissipate angular momentum, it can't fall to the center of the cluster.
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...
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.