Slashdot Mirror
"Dark Flow" Outside Observable Universe
DynaSoar writes "NASA astrophysicists have discovered what they claim is something outside the observable universe exerting an effect on the observable. The material is pulling clusters of galaxies towards a region of space known not to contain sufficient matter to create the effect. They can only speculate on what the material is and how space might differ there: 'In these regions, space-time might be very different, and likely doesn't contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.'"
Since no one reads TFA anyway, and since you clearly didn't:
The universe is thought to have formed about 13.7 billion years ago. So even if light started travelling toward us immediately after the Big Bang, the farthest it could ever get is 13.7 billion light-years in distance. There may be parts of the universe that are farther away (we can't know how big the whole universe is), but we can't see farther than light could travel over the entire age of the universe.
And then:
A theory called inflation posits that the universe we see is just a small bubble of space-time that got rapidly expanded after the Big Bang. There could be other parts of the cosmos beyond this bubble that we cannot see. In these regions, space-time might be very different, and likely doesn't contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.
Finally, on a side note, years of watching slashdot paid off in a truly interesting story!
An old-timer with old-timey ideas.
Maybe you should get one of those pumps.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
But I'd say if lots of really big things are being affected, then there could be a bigger thing out there.
It's a theory I know. I'd like to call it Cen's Big Fucking Thing theory, it's a big ball of stuff, chairs, signs, tanks, gravel and so on, literally sucking the universe dry of interesting stuff. A universal suck, maybe even a multiversal suck mechanism. Either way, I'm pretty sure we'll not see it coming.
Task Mangler
I'm actually pretty excited at this news. Granted, my understanding of astrophysics is limited to Hawking books and guests of George Noory (kidding, kind of). But I look forward to anything that seems to pin down the concept of 'dark matter'.
Dark matter to me has always smacked of a Victorian Era flimflam artist talking about the aether. And I don't care how dapper Mortimer T. Snerd is dressed, I'm not drinking his dark matter kool-aid until I can get a better explination for it than 'its invisible, supermassive, unobservable, and so totally there'. If you can't explain it to me, the interested layman, you may need to put your theory back in the crucible o' truth. Its probably not done yet.
-=Bang Bang=-
> NASA astrophysicists have discovered what they claim is something outside the observable universe exerting an effect on the observable.
The third episode of Brian Greene's "Elegant Universe" documentary miniseries on PBS said that while matter is confined to the known dimensions, its possible that gravity isn't and so can move through dimensions. The example they feel is that we could possibly detect the gravity of 'something' in another Universe by its gravity, even though we could never actually touch it. Wonder if this is it?
http://www.pbs.org/wgbh/nova/elegant/
The Dark Matter in US is pulling a ball busting amount of money away from tax payers to Large Banks.
In this area of Universe known as Capitol Hill and White House, the normal laws of space-time continumm is suspended so that banks which screw up your money get your money to bail out themselves.
"Doing what i can, with what i have." ~ Burt Gummer
Don't tell anyone, but when contrasting known information against an infinite cosmos...the average scientist is basically as clueless as the rest of us.
-=Bang Bang=-
i think it's kinda cool. the idea that there are even more massive structures out there than what's in our observable universe is really quite mind-boggling. but without stars and galaxies i wonder what kind of emergent structures or phenomena could exist beyond our observable bubble.
i'm guessing it's probably not possible for biological life to form in such a radically different environment, but then again maybe i just lack the imagination to conceive of such possibilities. it seems like within our observable universe for any biological life to evolve it must follow certain patterns dictated by the laws of physics/chemistry. but if space-time in these regions is so different from our observable universe then who knows? our level of consciousness compared to what exists out there might be like comparing an amoeba with a blue whale. even the time scales experienced by other life forms could be drastically different from ours. entire civilizations could spring forth and flicker out of existence all in the blink of an eye.
but since we can't even observe what is out there maybe this is all pointless speculation.
Yes I know, but we can see the galaxies travelling under the effect of this supposed dark flow. If we can see the galaxies being affected by these superstructures, then the light travelling to us from the galaxies which we now see left after the causal influence reached them, which means the causal influence had time to reach /us/. Which means the super structures aren't in the unobservable universe...
Cthulu waits.
At cosmological scales, metric expansion of space becomes very important. Light that left 13.7 billion years ago will actually travel 47 billion lightyears because of metric expansion. Since metric expansion implies space-time is curved (at cosmological scales, locally it is flat, like the earth is flat locally), general relativity comes into play. This means the normal causality described by special relativity is no longer applicable.
Imagine points A-B-C to be gravitationally bound. Because of metric expansion, space between A-B and B-C expands. This can cause A to move away from C at larger than lightspeed. Since space between B-C only expanded half of A--C, B will be withing light distance from C and thus visible by observers on C. Light from A can reach B, but it will never reach C. By the time it would, space between B and C will have expanded so much that observers from C will no longer see B.