Hundreds of Millions of Stars Racing Towards a Cosmic Hotspot (Aug 26, 2009). Could this be evidence of (Luminet's) 'wraparound universe' and a overlying 4D topology of the universe? An analogy would be hundreds of people who set off from the north pole in different directions (the big bang). The only place where they would tend to converge towards would be at the antarctic south pole during their wraparound globetrotting venture. Is this the same thing that is happening with the galaxies of our universe?
"Dark Flow" Discovered at Edge of the Universe
- Thread starter common_sense_seeker
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It doesn't tell you anything about the topology of the universe, only that there's likely some very big amount of matter which we cannot yet see, due to it being too far away, but which a lot of the matter in that direction can see, as they are close enough for light and gravitational forces to reach them from this large amount of matter.
Your example of people walking away from the North Pole to converge on the South Pole is not a good analogy as only some of the galaxies we see are moving to this 'hot spot', while your example would have everyone moving towards the same point.
Your example of people walking away from the North Pole to converge on the South Pole is not a good analogy as only some of the galaxies we see are moving to this 'hot spot', while your example would have everyone moving towards the same point.
I concede that this is the obvious alternative.
Not "everyone" necessarily, but the majority perhaps. It's a fair point.
More data will come in the near future I guess. Here's the latest article: The "Great Wall" Of Space: Galactic Superclusters a Billion Light Years Away Extend for 5% of Observable Universe (Aug 28, 2009).
What do you mean exactly, 'cranky'?
Did you read the article?
A billion light years!
The way I read this article is that it says the big bang is wrong. At a time when everything is supposed to be rushing away from everything else, the exact opposite is happening. It is more of a big collapse than a big bang.
Hyper-inflation? Didn't that stop at about cricket ball size?
I'm surprised no scientist has come out with the obvious answer (it took me 2 minutes) but that would take an original thought since you are not going to find it on wiki.
I didn't say it was a black hole, I said a lot of matter. A large region of space with more galaxies per unit volume than most of the universe, for instance. Huge structures like super clusters of galaxies are known to exist, this might just be a particularly enormous example.
You would read a cornflakes packet to be saying the big bang is wrong.
Inflation and continued universal expansion doesn't preclude gravitational collapse, even on scales as massive as that. Some regions of space will inevitably be more densely packed with matter than others, with those regions of particularly high density being those which will result in the largest gravitationally bound structures.
Rather than twisting what scientists say by your ignorant hyperbola why don't you try being honest and rational for a change?
And?
Yes, why bother spending years learning when you can just say "Bah, everyone is wrong except me" with only 2 minutes of effort.
Why bother expanding your horizons when its quicker and easier to dismiss anything you don't understand, which is a viscous cycle. You don't understand so you refuse to consider. You don't consider so you don't learn. You don't learn so you don't understand again. Repeat for ... how many years you been whining now Kaneda?Did You?
OK, then.You did not read the article. You read your preconceived notions into the article.
Just that the universe seems a little - you know - touchy when it's having its dark flow.
Edit: I don't mean anything by that of course. Just, you know, seems a bit...off. Maybe the universe needs some more iron.
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For perhaps 20 or more years, it has been known that our galaxies & others near us are moving toward what is called The Great Attractor.
A search for "Great Attractor" should result in data more recent & more accurate than the above, which is based on my not always reliable memory.
It seems that there is another Great Attractor somewhere. Perhaps the one mentioned in this Thread is some how different from the local attractor.
A search for "Great Attractor" should result in data more recent & more accurate than the above, which is based on my not always reliable memory.
It seems that there is another Great Attractor somewhere. Perhaps the one mentioned in this Thread is some how different from the local attractor.
http://www.sciforums.com/showpost.php?p=2303496&postcount=6
D H said:
D H started a new thread in Free Thoughts and put my name on it back in July 2009. The posts that I made on the Dark Flow topic in the Cosmology forum thread were moved from this thread for the reason stated by D H above. However he forgot to mention or leave an acknowledgement in the original thread that he had moved my posts. Now the topic has been brought up again in Cosmology and my speculations on the subject that apply to this new thread as well are sitting out there in Free Thoughts. I provide a link to the Free Thoughts thread from this thread so if anyone wants to see what is called over speculation on the topic of Dark Flow they can check them out. http://www.sciforums.com/showthread.php?t=94385&highlight=dark+flow
Getting back to dark flow without my speculation:
http://www.newscientist.com/article/mg20126921.900-dark-flow-proof-of-another-universe.html
Dark flow: Proof of another universe?
23 January 2009 by Amanda Gefter
Magazine issue 2692
FOR most of us the universe is unimaginably vast. But not for cosmologists. They feel decidedly hemmed in. No matter how big they build their telescopes, they can only see so far before hitting a wall. Approximately 45 billion light years away lies the cosmic horizon, the ultimate barrier because light beyond it has not had time to reach us.
So here we are, stuck inside our patch of universe, wondering what lies beyond and resigned to that fact we may never know. The best we can hope for, through some combination of luck and vigilance, is to spot a crack in the structure of things, a possible window to that hidden place beyond the edge of the universe. Now Sasha Kashlinsky believes he has stumbled upon such a window.
Kashlinsky, a senior staff scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, has been ...
The complete article is 2007 words long.
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Does this latest finding make the universe significantly 'lumpier' or more asymmetric than previously thought?
In mathematics the term asymmetric means the opposite of invariance and we can be confident that if in reality the universe is asymmetric then applying some geometry to it could be more difficult. Symmetry in that sense makes applying geometry easier and that is very useful by providing a common framework for discussing it. Spacetime is a good example of how successfully you can apply geometry if the universe is considered symmetric, i.e. invariant in geometry.
http://en.wikipedia.org/wiki/Symmetry_in_mathematics
But when talking about the universe without regard to geometry or existing theory my first thought is about reality and not mathematics. There is no way to tell if dark flow is a sign an asymmetric universe because symmetry can be equated to the cosmological principle. If the universe, lumpy or not, complies with the cosmological principle it is homogeneous and isotropic on a grand scale and then symmetry applies to it on a grand scale.
The difference is that the operative geometry has to accommodate a greater view of the universe if dark flow turns out to be a sign of other universes that could intersect and overlap with ours.
You once started a thread about a roar coming from deep space but never responded to any replies. I found that thread interesting too.
Is there anything new on those high altitude balloon experiments related to the "roar" and is there any connection between that roar from deep space and this dark flow in your opinion?
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We need a new term to apply to what we've been calling the universe, to distinguish it from the universe as a whole & cease saying silly things like other universes.
If there is more beyond the distance we are currently able to detect, that is yet part of THE universe not another universe.
If there are galaxies whose light hasn't had time to reach us, either the universe is older than currently thought and/or that part of the universe had a separate origin.
Perhaps there is a Great Attractor surrounding our part of the universe.
We need a new term to apply to what we've been calling the universe, to distinguish it from the universe as a whole & cease saying silly things like other universes.
If there is more beyond the distance we are currently able to detect, that is yet part of THE universe not another universe.
If there are galaxies whose light hasn't had time to reach us, either the universe is older than currently thought and/or that part of the universe had a separate origin.
Perhaps there is a Great Attractor surrounding our part of the universe.
Why? Space-time can expand such that two objects are 'carried' away from one another faster than light so it's possible for the universe to have expanded sufficiently fast that even over 14 billion years the light from some galaxies won't have reached us. It's like running on a conveyor belt, if you can't run fast enough you won't get where you're running to or it'll take longer.
So let me test my understanding of what you are saying about spacetime by putting it in my own words.
You are saying that:
Spacetime expands.
Spacetime can expand faster than the speed of light.
As spacetime expands it carries mass with it.
So spacetime can expand such that two objects are carried away from one another faster than the light that they have emitted travels.
I assume that is because the light that they have emitted is not carried with it as spacetime expands?
Or is light also carried with it as spacetime expands?
And if light is carried with the expansion of spacetime, and if the light emitted by two objects has not reached to each object, then the "faster than light" expansion between the two objects means that the light will never reach. If so then is that because the expansion of spacetime can't accelerate light while it can accelerate mass faster than the speed of light?
Why wouldn't light travel faster than the speed of light if it was being carried along with the expansion of spacetime?
And if light is carried with expansion also, you seem to be saying that in spacetime the speed of light light is not invariant?
Clear this up for me: Does light get carried along with the expansion of spacetime just like mass?
If so does this mean that the speed of light is not invariant?
If you don't mind, I will jump in here to advance your understanding of the current consensus of our expanding universe.
Correct, spacetime, the aether, the Dirac sea or whatever else one may wish to name the vacuum of space.
To be more precise, two points in spacetime can separate faster than the speed of light if they are located far enough apart.
Well, neither mass nor spacetime moves in the local spacetime, so it is a bit of a misnomer to say that mass is "carried" by spacetime.
Yes, other than the reference to 'carried away'.
An object is not moving in its local spacetime, at least due to the expansion. The local spacetime is not moving relative to the object. Emitted light cannot be 'carried' because the local background is not moving.
I'm not sure I understand exactly what you refer to when stating "carried with it". The speed of light will always measure as 'c' in a local frame of reference. Perhaps it is easier to think of the volume of space increasing over a period of time, say one billion years. Say two objects in space are separated by one billion lightyears when a photon is emitted by each object toward the other object. While those two photons are travelling through space, the volume of space each must travel through is increasing over time. Even though the photon is always travelling a 'c' when measured in its local spacetime, it can take each photon much longer than a billion years to complete their respective journeys. Do you understand the true meaning when cosmologists state that the rate of expansion is increasing? Consider those two photons that were emitted when two objects were one billion lightyears apart. Assume those two objects were very distant to us, both located in the early universe when it was only four billion years old. Now assume two more objects emit photons when they are located one billion lightyears apart, but both of those objects are located closer to us in the modern unverse. It takes longer for the photons in our modern universe to complete the 'original' one billion lightyears trip than for the photons in the early universe. The rate of expansion is increasing. The rate of expansion was actually decreasing slightly until about seven or eight billion years ago, then the rate started increasing.
Got to leave for now, will continue my post at a later time.