Aliens: Yes Or No?

[Parmandur]

There is no current scientific consensus on whether the universe is infinite or finite, we simply do not know with any certainty.

Consensus is difficult. Bit all the evidence I've ever seen leans towards finite in time & space.

 

[tomBitonti]

Consensus is difficult. Bit all the evidence I've ever seen leans towards finite in time & space.

I think the consensus would be be that the question is a-scientific. Absent data via a test / experiment that can be repeated, there is no science to be done.

There is somewhat a basis for the universe being larger than we can observe, and that the parts that we cannot observe are about the same as what we can observe, which is, as I understand it, physics works the same everywhere, and, we do not have a distinguished place in the universe. Note that those are general principles which have worked so far, but are more useful guidelines than physical rules.

TomB

 

[Parmandur]

I think the consensus would be be that the question is a-scientific. Absent data via a test / experiment that can be repeated, there is no science to be done.

There is somewhat a basis for the universe being larger than we can observe, and that the parts that we cannot observe are about the same as what we can observe, which is, as I understand it, physics works the same everywhere, and, we do not have a distinguished place in the universe. Note that those are general principles which have worked so far, but are more useful guidelines than physical rules.

TomB

Fair.

 

[Parmandur]

I think it is interesting that just about as many people believe there is no extraterrestrial intelligent life as they are people who believe they are already among us.

As to the recent UFO kerfuffle, it smells of the Air Force pulling tricks to obfuscate their research breakthroughs and intimidate enemies. As has often been the case with past UFO "leaks".

 

[Umbran]

We're kind of a sad case...

Don't fall into the idea of human exceptionalism. That goes for being exceptionally good, or exceptionally bad. If we must make an assumption, it is reasonable to guess that our problems are kind of generic, and everybody else who might be out there face(d) much the same difficulties we do.

 

[Umbran]

Consensus is difficult. Bit all the evidence I've ever seen leans towards finite in time & space.

I believe current understanding is mostly that what you say here is incorrect.

There is finite space in the observable universe, because our observations are limited by the speed of light. However, there is nothing particularly weird that happens at the edge of that observable universe - implying the universe just... continues beyond that.

Our observations within the observable universe are that it is, on large scales, perfectly flat - it doesn't curve back in on itself, or curve outwards. We know that to within about one part in 400. Barring any reason to assume that the universe radically changes outside the visible part, that means the overall universe is at least 400 times the radius of the visible universe - which means the full universe has at least 64 million times as much space as we can see, and no particular reason to think that it curves back in on itself at all.

There is a known limit to time in the backwards direction - the big bang is t=0 on the great cosmic clock, because "time" as such doesn't exist before that point - indeed "before that point" is a meaningless statement. But, we don't see sign that time is curved back on itself either. And while the universe might continue forward in time to the point of heat death, after which time is... pointless, I guess is the right word, there's no particular reason to think time just stops in the forward direction any more than to think that space just stops.

 

[le Redoutable]

Then, crystal spheres ?

 

[ichabod]

Our observations within the observable universe are that it is, on large scales, perfectly flat - it doesn't curve back in on itself, or curve outwards. We know that to within about one part in 400. Barring any reason to assume that the universe radically changes outside the visible part, that means the overall universe is at least 400 times the radius of the visible universe - which means the full universe has at least 64 million times as much space as we can see, and no particular reason to think that it curves back in on itself at all.

Okay, but even if the full universe is 400 times the size of the observable universe, that's still finite.

 

[Whizbang Dustyboots]

You may think it's a long way down the road to the chemist's, but that's just peanuts to space.

 

[Corinnguard]

Then, crystal spheres ?

If the crystal spheres were a more solid version of the Heliosphere. Heliosphere - Wikipedia