duckiegooseman t1_j1goass wrote
Reply to comment by TLRsBurnerAccount in Did you know it will still take 46 billion years to cross the universe at the speed of light? 65 mph = 4.8 * 10^17 years! by NotAndroid545
Looks exactly like what you see from earth because it doesn't have an expanding edge, but rather the space between "things" just get bigger, so to an observer sufficiently far away, earth is on the edge of their observable universe
Artikay t1_j1gszt9 wrote
So if you place Earth in the center of our observable universe, and call it Planet A, then you take two planets on the far opposite ends and call them B and C. Does that mean to Planet A, B and C can be seen, but to planets B and C only Planet A can be seen?
Basically B and C have more than one observable universe between them? It would take exponentially longer for light to reach between stars because there is more space to expand between them?
If there is so much space between ends of the universe could two points be so far apart that light could never get from one end to the other?
Wind_14 t1_j1gu400 wrote
the last one is the consequences of observable universe though. Yeah there's a point where light simply can't reach the other side, because the expansion is faster than the speed of light, thus limiting the size of the observable universe (of course, this is assuming our prediction/projection is really true which is the farther an object is from the center the faster the expansion rate is between them and center).
And you don't have to assume that earth is the center of our observable universe, since it is (or rather the center of your observable universe is you).
duckiegooseman t1_j1hf4ic wrote
Yes to the last question. Actually since the universe is accelerating faster than light, every second more and more "things" get so far away they are "lost" to us permanently because light from them can never reach us anymore. At some point far far into the future, our cosmic horizon would be complete emptiness in every direction, and our galaxy would be the only thing that even exists to us anymore.
But to B and C, they don't exist for each other. Information from B can never reach C and vice versa.
TLRsBurnerAccount t1_j1gp27x wrote
I guess what I mean more I wonder what it's like being beyond the edge of the universe and essentially being crested by the edge
420binchicken t1_j1gpqoh wrote
AFAIK that’s not really how it works. For them, they are the centre point at which the universe is expanding from. It’s all relative to your own frame of reference. No solar system is more on the ‘edge’ of the universe than any other.
Please someone correct me if that’s wrong. Space is big and weird.
inventionnerd t1_j1gs85e wrote
This is true if we're going off the belief the universe is infinite. Then yes, everyone can only see in a 46b radius and are therefore at the "center" of their universe.
sbrt t1_j1gtcr9 wrote
It was explained to me that it is the 3d equivalent of a 2d creature living on a globe that is expanding. I can imagine that but I have no idea if it is accurate.
ZincMan t1_j1i1jce wrote
Can we judge our location in relation to the “true” center of the universe ? I mean I assume if the Big Bang was centralized, there must be a “core” to that expansion where everything is expanding radially outward…. But now that I think about it, it still might appear as though everything in relation to you is leaving your observable edge of the universe at equal speed regardless.
inventionnerd t1_j1i2ctp wrote
It wasnt centralized though. Basically the current theory is the universe is/was always infinite and is just a bigger infinite now. The mass might have been far denser and closer together before the space expansion, but it wasnt in like a 1 mm radius sphere or something. It was always in an infinitely sized space.
gtga1976 t1_j1i4b96 wrote
That's space itself though yes? I assume the mass within space shows differential in red shift relative to earth based on some other central point? Or are you saying everything is travelling away from earth at the same speed?
inventionnerd t1_j1i8w3u wrote
Not quite sure what you're saying, but no, everything isn't traveling from Earth at the same speed. But I'm saying wherever you are in space, you'd see the same frequency if you look far enough as you see on Earth? So, our observable universe is about 46b lightyears in radius. To us, we're at the center right? We see a redshift of x when looking straight "up" to the very edge of our universe. If we can teleport to this this spot instantly and look around us, we'd still see a universe of about 46b lightyears in radius (just would be mostly different things as you could see from Earth. If you then looked straight "up" from this spot, you'd still see the same redshift of x as you saw when you looked at your current spot from Earth. So, how could you ever tell what the central point is if everywhere you go, you'd have the same size observable universe and same shifts?
The_Most_Superb t1_j1gu3pk wrote
There is only existence and non existence. Beyond the universe is nothing. Unfathomable nothingness.
Caveman108 t1_j1gwkoj wrote
Except we don’t know that. If you could travel multiple times the speed of light, ideally many multiples, you could reach the edge of the observable universe. There you very well might just find more universe. We don’t know there’s an “edge.” Just an edge of what we can see.
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