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"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.'"
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=-
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=-
You can't see ships past the YOUR horizon, but those ships could certainly see other ships that you can't see that are beyond YOUR horizon, but not theirs.
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...
If we are observing far-away galaxies being affected by the stuff too far away for us to observe directly, maybe we are observing the stuff outside our bubble indirectly? This visibility can be transitive?
Also, maybe we can also "observe" the stuff outside our bubble via the effects of "spooky action at a distance"?
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
Your reasoning is trapped by trying to imagine the universe as some defined boundary expanding. It's the same reasoning that images the Big Bang as an explosion in space.
The bang wasn't an explosion in spacetime, it was an explosion of spacetime. The expansion of space just means that the metric which measures distance between two points that stay at the same location changes. As time passes, two points which stay at the same location on some hypothetical reference grid will first measure one foot apart, then two, then five, etc. They aren't going anywhere, they're being carried along on space itself.
i think life is possible in almost any kind of environment. just look at the so called fragile state of life as we know it - bacteria that thrives in nuclear reactors and in boiling water. from what i've obversed life isn't fragile OR rare, but tough enough to adapt to anything and populating to the extent it seems like a cosmic imperitive.
If you mod me down, I will become more powerful than you can imagine....
This is why examples fail. There is no physical "horizon" like there would be on earth, the only "horizon" is time and the speed of light. To try to repair the ships example, the horizon would be expanding away at cannonball speed, thus when you see the first ship hit by a cannonball, you should logically bee able to see the ship that fired it at the same time, if not earlier. Thus if you see a ship hit by a cannonball, and don't see the ship that fired it, you might assume that the cannonball somehow travelled above cannonball speed. Or not, since this example isn't complete: The ocean is also expanding between you and the ships, and betwen the two other ships. To summerize, the naval analogy isn't really optimal for this problem.
It's contradictory anyway. If we're seeing something influenced by it, then we ARE observing it. That's what observation MEAN.
If you're "watching" something, you're really interpreting electrical signals generated by your retina in response to chemical reactions triggered by photons, nothing "direct" about it whatsoever.
So saying we're seeing something being influenced by something outside the observable universe is nonsense.
Yep you're right, but *I think* they're talking about a different horizon to the one you're thinking of (the summary doesn't make this clear).
The furthest back we can see is the CMBR, due to the Universe being opaque any earlier on. This opacity creates a horizon at a slightly shorter distance than the horizon you would get due to the fact that light/changes in gravity fields propagate at c.
The abstract (linked below) mentions that they suspect it is gravitational influences from beyond the CMBR barrier (but before the speed of light barrier) that is producing the effect:
"... and may be indicative of the tilt exerted across the entire current horizon by far-away pre-inflationary inhomogeneities." ... at least that's how I translate the above.
Humans are insignificant for the terms of the universe, but we at least strive to understand it.
We haven't yet fully understood the universe, and even if we do it's so large that it's hard to fathom the span of it.
And did the universe really exist before the big bang or was it created by the big bang? How can one prove something that is hypothetical if we don't have something to measure it against?
Anyway - it is possible that what attracts matter is nothing more than an inert part of matter - or more specific a black hole that currently is invisible because it has consumed all matter near itself a long time ago.
The Big Bang wasn't a "perfect" explosion, and if it had been we wouldn't have had the distribution of galaxies that we have - it would have been a cloud of gas. And since we haven't had a perfect explosion it is possible that the black hole was created at a very early stage of our universe.
But who knows in reality?
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Therefore, claiming that there could be "giant, massive structures much larger than anything in our own observable universe" just outside this bubble seems somewhat... convenient.
"giant, massive structures much larger than anything in our own observable universe" is the new "here be dragons".
You just got troll'd!
First, the region that these clusters are supposedly moving towards are pretty close to being in line with the heart of the Milky Way. What this means is that the attractor object may simply be obscured by our own galaxy.
It's not just the lack of an attractor object, it's the unusual velocities.
Second, the motion is not unusually large for superclusters.
They argue otherwise: "If produced by gravitational instability within the concordance LambdaCDM model, the motion would require the local Universe out to ~ 300h^1 Mpc to be atypical at the level of many standard deviations of the model", and argue that even a 100 km/sec motion due to local gravitation alone would be excluded by observations. I confess that I don't know enough cosmology to understand why. Either you expect smaller motions in the earlier universe or else there are additional constraints at work (they mention having to explain why the dipole is approximately constant with depth). I'd have to do more background reading to understand what's going on here, but the point is that they say they have reason to believe that the motion is unusually large.
What really bothers me here is the claim that these bodies are still experiencing forces from the long departed rest of the universe.
I don't think they are. From my reading of the paper, it sounds like this motion is left over from the inflationary phase.