|
|
| 13 Jan 2018 06:08 PM
|
if the universe is expanding, how can we be sure that it won't reach the point of maximum expansion, and just stay there forever?
i mean, it's like our universe is an air-filled balloon; if you keep blowing it up for long enough, eventually it'll become so big that you can't make it bigger anymore. at that point, it's going to stay at max size forever.
so...isn't that what's gonna happen with the universe?
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:12 PM
|
A lot of people believe that the universe is going through cycles of expansion and contraction (Big Bang, Big Crunch) or that it will continue expanding infinitely.
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:19 PM
|
why are they all so sure? it seems that the only real evidence we have is that space is expanding now. and even then, we don't know for sure if it's happening now; it could've been like this at any point in time.
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:22 PM
|
People say it will keep expanding because if it does, they can calculate how much energy would be needed to stop it and use that to estimate the amount of dark matter/energy in the universe which is a lot of money
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:24 PM
|
@iDoaBarrelRoll
We do know for sure because it was predicted by General Relativity
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:26 PM
|
but how did general relativity predict it?
what was the evidence?
|
|
|
|
|
|
|
Report
Abuse
|
|
|
|
| 13 Jan 2018 06:29 PM
|
Well, let's see.
If you look at a picture of the Big Bang (google images) you'll notice that it looks like a bunch of red and blue dots which are galaxies being stretched out by gravity. If you look closely, you'll notice that most of them are red with a few blue ones here and there. This is due to the fact that space is expanding faster than light meaning that everything is moving away from us faster than the speed of light. The red dots are far away, but we can still see them since their light has been traveling towards us for quite some time and is now reaching us. The blue dots are much closer to us and their light has just started reaching us and hasn't had enough time to reach us yet so they're not visible.
|
|
|
|
|
|
|
Report
Abuse
|
|