Australian Study Backs Major Assumption of Cosmology 94
cylonlover writes "In mankind's attempts to gain some understanding of this marvelous place in which we live, we have slowly come to accept some principles to help guide our search. One such principle is that the Universe, on a large enough scale, is homogeneous, meaning that one part looks pretty much like another. Recent studies by a group of Australian researchers have established that, on sizes greater than about 250 million light years (Mly), the Universe is indeed statistically homogeneous, thereby reinforcing this cosmological principle."
on smaller scales as well (Score:5, Funny)
Once you've seen one suburban shopping mall, you've seen them all.
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>Once you've seen one suburban shopping mall, you've seen them all.
"If you've seen one shopping center, you've seen a mall."
Down under (Score:5, Funny)
So the laws of physics still hold in Australia at least.
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Re:Down under (Score:5, Funny)
Gravity works backwards down there too, so it pulls them up, which is down.
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Hold up a ball. Which side points to the earth? What happens when you drop it? Will it always fall towards the earth? Now, go to Australia. Which side of the ball faces the earth? What happens when you drop it? If you drop the ball, will it fall towards the earth? If so, that's why they haven't fallen off.
Really?
You should really get some sort of Nobel prize for finally solving that particular puzzle.
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Aliens? Probably. (Score:2, Offtopic)
Aliens who visit us, dismember our cattle and probe us? No.
Extra-solar planets with intelligent life? Probably. Given the sheer size of the universe and the number of solar systems and planets there are quite likely some out there with intelligent life (within range of detection is a different matter). Given enough rolls of the dice you're bound to hit on any given combination more than once.
Re:Aliens? Probably. (Score:4, Informative)
More to the point would we recognize intelligent life even if it was in front of our face.
Re:Aliens? Probably. (Score:5, Insightful)
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...an argument often, rightly made here on earth.
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More to the point would we recognize intelligent life even if it was in front of our face.
There's a television joke in here somewhere....
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More to the point would we recognize intelligent life even if it was in front of our face.
There's a television joke in here somewhere....
There's also a slashdot joke, but I'm not sure many people here would appreciate it.
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More to the point would we recognize intelligent life even if it was in front of our face.
Probably not, because it would be too different from us.
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Aliens who visit us, dismember our cattle and probe us? No.
Extra-solar planets with intelligent life? Probably. Given the sheer size of the universe and the number of solar systems and planets there are quite likely some out there with intelligent life (within range of detection is a different matter). Given enough rolls of the dice you're bound to hit on any given combination more than once.
This pre-supposes that "intelligent life" is a possible result. It may be that much like you can't roll 42 on 2 six sided dice, intelligence is just not possible in this universe. Were that the case, any intelligent life to think you have found is merely an illusion cause by your inadequate intelligence.
As has been pointed out many times before, we know with 100% certainty that there is intelligent life in the universe, because we are it.
If the argument is that humans aren't necessarily intelligent on a universe-wide scale, how do you know? What are you comparing us with?
Re:Aliens? (Score:5, Informative)
(and, shouldnt that be a unit of volume, not length?)
When talking in terms of scale, it's generally better to use fundamental units, not derived ones. Volume is derived from length (length^3), so a volume scale is inherently a length scale, but less precise. If you were to use a volume scale, say 250Mly^3, then that could mean different averages looking in different directions (i.e. the universe is homogenous every 250kly looking up, every 10ly looking left, and every 100ly looking forward). Just using a length scale ensures all 3 dimensions are covered equally.
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But is it a cube or a sphere (your description implies sphere but your definition implies cube)? If a sphere, is that a radius or a diameter? There's a reason that we use volume as a dimension......volume doesn't depend on shape.
Re:Aliens? (Score:4, Informative)
There's a reason that we use volume as a dimension......volume doesn't depend on shape.
There's a reason that we don't use volume as a measure of scale - volume doesn't depend on shape. That's my entire point. When you're dealing with scale, it doesn't matter if it's a sphere or a cube, because we're dealing with statistical averages, not defined physical limits. The difference between a sphere and a cube of D=S is dwarfed by the difference between a sphere and a hugely-eccentric ellipsoid of equal volumes. The point is homeogeneity. We want to be clear that the average pointing one direction is the same as the average pointing another direction. You can't do that with volume.
It's a hidden message! (Score:2)
No, it just implies that you have to go 250MLY that way.
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i.e. the universe is homogenous every 250kly looking up, every 10ly looking left, and every 100ly looking forward
That doesn't sound very homogeneous.
(Yes I get what you're saying and agree. It just sounded funny)
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There is also the factor we don't know how many earth like planets with life exist in our 250 million light year rage. You are assuming that there is only 1.
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Or.....assuming there is AT LEAST 1 (slight difference in mindset).
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So, does that mean there is atleast one Earthlike planet with life on it every 250 million light years?
No. Statistics don't work that way. It might mean there is, on average, one Earthlike planet per given volume of space, but certainly no "at least" guarantee, and indeed if the average is that low, there will be many instances of zero in said volume.
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Statistically speaking, isn't the universe empty?
Given that particles and anti-particles are continually being "produced" by quantum effects out of (seemingly) nothingness and disappearing only moments later, and given that we understand that we observe an enormous gap in measurable (luminous vs. non-luminous matter) mass in the universe, and add to this the potential category of supersymmetric particles, a powerful argument could be made that space is quite cluttered, if not densely packed.
INAS - perhaps an wizard from Fermilab or Hogwarts can flesh out
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42
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No. Well, probably not. That's one problem in cosmology that goes back a few hundred years (at least to the time of Netwon through Einstein). Not sure what the current theory states about it.
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Define "Earthlike." Certainly, for example, there are other terrestrial planets in the universe. There are probably even some with a similar mass to ours, at a similar orbital distance from a similar star. But this still doesn't account for, for example, when in their history such planets might be. Life might not have begun on all of them, or it might have already ended, or what life exists might not have reached the state of relative advancement we enjoy today.
Bottom line: yes, there are probably planets w
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They're already here. Under your grounds. Up in yer caves.
And they call themselves the Earthlings.
Join the fight against the greys and reptiliods today! Don't believe them when they say they created you in a test tube or that they're the good guys. They're after our natural metaphysical abilities. Kill them at first site.
Re:Aliens? (Score:4, Interesting)
For scale:
Milky way diameter ~ 0.11 Mly,
Local Group (Milky way, Andromeda, etc...) diameter ~ 10 Mly,
Virgo Supercluster diameter ~ 100 Mly.
The existence of superclusters is part of why local homogeneity is not observed. However, the claim is only that any given region of about 250 Mly is on average about the same as any other region of the same size. So, even if that homogeneity holds true as you reduce scale (i.e. look for an average Earth) there's still a huge difference in thinking that you've got AC posters on alt-Earth asking about their alt-Australian universe homogeneity study. Besides, the frequency of Earth like planets should be signnificantly higher within our own statistically homogeneous region, but we still haven't had cookies dropped off from our older-to-the-hood neighbors. Check out the Fermi Paradox [wikipedia.org] for fun reading.
Actually - there's some discussion to having been visited in prehistory and early history earth, but that's a subject for an alt. and not an alt-
;)
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No, because this universe was generated before Mojang tweaked the chunk-creation code to stop producing so many life-supporting worlds.
Goddamn nerfs...
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This doesn't change much. As mentioned, this is a pretty fundamental assumption. What this assumption gets you is that if you go big enough, all of the differences in mass distribution smooth out and everywhere is just like everywhere else. There will be a "typical" cluster of galaxies that "most" are "pretty close" to. And within such a typical cluster you can talk of a "typical" galaxy, and a "typical" star within that galaxy. But are we a typical planet in a typical solar system in a typical galaxy
Sounds a lot like Southern California (Score:4, Funny)
Well, except for San Bernardino.
huge scale (Score:1)
If anyone is trying to visualize that scale, it might be more convenient to consider that 250 million light years is simply 4.70279985 × 10^23 rods
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But some ethnic groups have shorter rods.
No matter where you go... (Score:1)
I knew it... (Score:3)
A good foundation will cover those blemishes and make the subsequent layers easier to apply.
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Well, 90% chance you are in fact trolling, but just in case: white knighting like you're doing right now is the worst form of discrimination against women. Women are perfectly capable of standing up for themselves if they are offended. They are not weak, fragile flowers who need you to rise to their defense, and you insult them by doing so.
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Well, 90% chance you are in fact trolling, but just in case: white knighting like you're doing right now is the worst form of discrimination against women. Women are perfectly capable of standing up for themselves if they are offended. They are not weak, fragile flowers who need you to rise to their defense, and you insult them by doing so.
Yeah, but if the OP hadn't said he was male, all the slashtards would have assumed it was a woman and started with the "show us your tits" comments.
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I have never once seen that on /.. This is not /b/, this is not digg, and those are not tech sites (even by the stretch that /. is one).
Visualizing The Scale (Score:5, Interesting)
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It's pretty far also :-(
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You think that's far? You should see how far it is to the chemist.
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Excellent Douglas Adams reference.
Which was quoted at the top of TFA.
I know, I know...
the idea that it loops and we see old stuff-- (Score:3)
So, isn't there a concept that the Universe is closed, and we're just seeing older versions of the same stuff, but kinda repeated? (but hard to recognize because of the time lag involved)
Is this still considered a possibility, or have they figured out a way of ruling that out?
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Good, it's not too late to kill Lady Gaga's great grandparents.
Re:the idea that it loops and we see old stuff-- (Score:4, Informative)
It was pretty much ruled out by the cosmic background microwave radiation surveys. Because that's a point-in-time snapshot of the universe, seeing the same stuff repeated in layers would really stand out. The visible universe is a subset of the universe.
And the universes' population: (Score:4, Funny)
None. Although you might see people from time to time, they are most likely products of your imagination. Simple mathematics tells us that the population of the Universe must be zero. Why? Well given that the volume of the universe is infinite there must be an infinite number of worlds. But not all of them are populated; therefore only a finite number are. Any finite number divided by infinity is as close to zero as makes no odds, therefore we can round the average population of the Universe to zero, and so the total population must be zero.
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He's quoting the Hitchhiker's Guide to the Galaxy. So it's not his logical gap or his own problem. It belongs to Douglas Adams.
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It's homogeneous... (Score:3)
...but is it pasteurized?
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In fact it's been ultra-super-duper-insanely pasteurized, though what with it been sitting around for a few billion years since then I think life may have crept in.
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I shall continue to milk this joke-line until the cows come home, or until everyone grows sour to it and they start carton us away.
Self Portrait? (Score:2)
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We know that's not the case from the cosmic background microwave radiation surveys. Repeated patterns would had really stood out statisically, but that's not what we see.
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The CMBR is a snapshot of the universe at a point in time long after "inflation" (if inflation even happened, that's still speculative). Normal expansion of the universe is easily adjusted for.
2 Mly? (Score:2)
This research is false. (Score:4, Interesting)
Until the Billion light-year across VOID is explained, this article makes no sense! http://www.newscientist.com/article/dn12546-biggest-void-in-space-is-1-billion-light-years-across.html
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Dear AC, the fact that with an infinite number of coin tosses you should tend to average tails half the time? It in no way prevents you from rolling heads several times in a row - or a billion times, for that matter.
The gizmag article is about statistical homogeneity while the newscientist article is about an empirical anomaly. The two are quite compatible in that respect.
It should also be mentioned that the fine article mentions the study is ongoing and has only mapped less than 1% of the observable univer
...for the obsrvable universe only (Score:4, Interesting)
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If the universe is infinite, then this observation says nothing about the non-observable universe. Any statements about the non-observable portions are purely assumptions.
Of course, the thing about the non-observable universe is that as far as we care it might as well not exist.
Really glad about that (Score:2)
And the Australian Government (Score:2)