Are we alone?

[Wayne]

Amongst a few, it's considered they invented: roads, plumbing, law, welfare and fast food shops.

Apart from roads, plumbing, law, welfare and fast food shops What have the Romans ever done for us?

 

[Nishy]

Apart from roads, plumbing, law, welfare and fast food shops What have the Romans ever done for us?

Prosecco

 

[efsk]

Given that “universe” means all of space and time and everything in it, what’s outside it?

Good question.

I don't really get the point you're making.

I dispute "infinite", and the claim that one infinity causes another.

 

[sɐǝɹpu∀]

Yes the universe is finite but it's expanding into possibly infinite space.

My understanding: Space/time is part of the universe. There is no concept of space/time outside the universe, therefore the universe, while expanding can't expand "into" anything.
Is the universe finite? While there is no proof for that, the concept of an infinite universe has horrendous implications that my brain refuses to accept. It's absurd. Doesn't mean it isn't so, but I'd rather hope it isn't.

To quote Douglas Adams (a great author, but not a physicist or mathematician)

Space is big. Really big. You just won’t believe how vastly hugely mindbogglingly big it is. I mean you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

Doesn't mean it's infinite.

 

[Boru62]

My understanding: Space/time is part of the universe. There is no concept of space/time outside the universe, therefore the universe, while expanding can't expand "into" anything.
Is the universe finite? While there is no proof for that, the concept of an infinite universe has horrendous implications that my brain refuses to accept. It's absurd. Doesn't mean it isn't so, but I'd rather hope it isn't.

To quote Douglas Adams (a great author, but not a physicist or mathematician)

Doesn't mean it's infinite.

If we had the capability, the universe could possibly be measured at a moment in time, therefore it's possibly finite.
The fact that it is both growing and dying also show that it's possibly finite.
I really can't conceive an organism being infinite.

p.s. it is a long way to the chemists and they never had any peanuts.

 

[MntnMan62]

If we had the capability, the universe could possibly be measured at a moment in time, therefore it's possibly finite.
The fact that it is both growing and dying also show that it's possibly finite.
I really can't conceive an organism being infinite.

p.s. it is a long way to the chemists and they never had any peanuts.

I’m confused. How do we know the universe is growing?

 

[Boru62]

I’m confused. How do we know the universe is growing?

https://www.independent.co.uk/news/...-latest-image-picture-telescope-a8426451.html

 

[MntnMan62]

https://www.independent.co.uk/news/...-latest-image-picture-telescope-a8426451.html

Ok. So new planets are being formed. That makes sense to me. But when we talk about the Universe being finite or infinite, does that not relate to whether it has borders or an end?

 

[Boru62]

Ok. So new planets are being formed. That makes sense to me. But when we talk about the Universe being finite or infinite, does that not relate to whether it has borders or an end?

It's expanding into unoccupied space, what can the barriers be made from?

 

[sɐǝɹpu∀]

I’m confused. How do we know the universe is growing?

Red shift. An object (star/galaxy) moving away from us has its colour shifted towards the red spectrum Doppler effect, like a police car's siren's frequency is getting lower moving away from you - works with light as well.
Every far away galaxy we observe from earth has light shifted towards red, so they are all moving away from us. Also, the further away they are the redder they are, so they also move away from each other. That's best explained by the universe expanding. It's not that galaxies actually fly away from each other, the space between them expands. Tricky to get your head around, but easier than - for example - an infinite universe.

 

[MntnMan62]

It's expanding into unoccupied space, what can the barriers be made from?

Exactly.

 

[sɐǝɹpu∀]

Ok. So new planets are being formed. That makes sense to me. But when we talk about the Universe being finite or infinite, does that not relate to whether it has borders or an end?

Imagine you are a being living in a two-dimensional world. Like the surface of a balloon that's being blown up. For you, every point on your world is moving away from all the others, yet the balloon's surface has no borders and no end. The universe is just like that, except it is 3D, and it went "bang" at the beginning, not at the end. I may be over-simplifying ever so slightly.

 

[MntnMan62]

Red shift. An object (star/galaxy) moving away from us has its colour shifted towards the red spectrum Doppler effect, like a police car's siren's frequency is getting lower moving away from you - works with light as well.
Every far away galaxy we observe from earth has light shifted towards red, so they are all moving away from us. Also, the further away they are the redder they are, so they also move away from each other. That's best explained by the universe expanding. It's not that galaxies actually fly away from each other, the space between them expands. Tricky to get your head around, but easier than - for example - an infinite universe.

So, while the planets and constellations and stars are still being created, the planets, stars, constellations are spreading out, further away from one another. That still leaves the possibility that there is no limit to how far apart they can move, meaning that space itself could be limitless. No end to it.

 

[sɐǝɹpu∀]

So, while the planets and constellations and stars are still being created, the planets, stars, constellations are spreading out, further away from one another. That still leaves the possibility that there is no limit to how far apart they can move, meaning that space itself could be limitless. No end to it.

I have to borrow that balloon again. The things in the universe don't actively move away from each other, the space between them stretches, like the surface of the balloon. Each point on the balloon doesn't move across it, the space between them gets bigger. And while the balloon's surface gets bigger and bigger, it never gets infinite.

 

[Boru62]

So, while the planets and constellations and stars are still being created, the planets, stars, constellations are spreading out, further away from one another. That still leaves the possibility that there is no limit to how far apart they can move, meaning that space itself could be limitless. No end to it.

The space is most probably infinite but that doesn't mean the universe will become infinite.