As far as we know the universe is expanding because of the explosion at the Big Bang which causes everything to expand out from that first explosion. What is it expanding into? The space outside the universe, although no-one really has a clue what that might be. The best idea is just nothing, there’s just nothing there but who knows?
Hi coca-cola
Got to agree with Robert regarding what we already know, but I have always wondered if it is expanding and continues to do so, would it be possible for two solar systems to come together and for planets to change orbits……obviously not anytime soon, but sometime? Just a thought!
The universe is expanding because of the big bang – if you think of explosions you get a growing area of exploded stuff – and the universe is doing that in super slow motion. As to what it’s expanding in to – our best guess is nothing! It’s just expanding. But who knows, there’s still so much we don’t understand we might discover something outside of the universe
ok, I know I’ve been evicted, but I do like the odd ‘space’ question
There does seem to have been something special happen at the ‘Big Bang’ where everything was very hot and very compressed (how it got this way no-one knows) and since this moment the universe has been expanding. Exceptionally rapidly at first, then more slowly, and the latest observations suggest the expansion is speeding up again (but its difficult to tell for sure). ThE speed of this expansion, given by the Huble constant, is now approximately 70km/s per megaparcsec (so an average galaxy 3.09×1019 km away is moving 70km/s away from us)
As for what its expanding into… You could simply define the universe as ‘everything’ so there is nothing ‘outside’ it. But even if there is an ‘outside’, I wouldn’t call it ‘space’. The universe is not an object ‘in’ space it *is* space (and stars and gasses etc) itself. The typical model system use to describe this is a rubber balloon:
Imagine the entire universe as the surface of a balloon (ok you have to pretend that the universe only has 2 space dimensions rather than the more usual 3, but it makes it easier to imagine!).
So the Big Bang can be thought of like this – Draw spots on the balloon to represent the stars and galaxies and start inflating the balloon. You should notice all the spots start moving away from each other as the balloon/universe expands… It is not that the galaxies are moving around rapidly, but the space/rubber in between them that is expanding.
As for what is it that the universe/balloon is expanding into – As I said I wouldn’t call it ‘space’. Space in this model is the rubbery material that makes the balloon… the rubbery fabric of the balloon doesn’t expand into more rubber.
Essentially, the question ‘what is outside space’ is (for the moment) outside the experience and experimental techniques open to humans… it could be nothing, or something… but it almost certainly isn’t ‘space’, since space is what the universe is made of.
There might be a way of probing what lies ‘outside’ the universe if for example we were to notice the values of what we thought were fundamental constants (for example the G of Newton) started changing. This sort of thing is what might be expected if a ‘neighbouring universe’ moves relative to ours (in the balloon model, this would just be two balloons moving past each other). If this were to happen, you might be able to find out something about the intervening material.
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Ian commented on :
ok, I know I’ve been evicted, but I do like the odd ‘space’ question
There does seem to have been something special happen at the ‘Big Bang’ where everything was very hot and very compressed (how it got this way no-one knows) and since this moment the universe has been expanding. Exceptionally rapidly at first, then more slowly, and the latest observations suggest the expansion is speeding up again (but its difficult to tell for sure). ThE speed of this expansion, given by the Huble constant, is now approximately 70km/s per megaparcsec (so an average galaxy 3.09×1019 km away is moving 70km/s away from us)
As for what its expanding into… You could simply define the universe as ‘everything’ so there is nothing ‘outside’ it. But even if there is an ‘outside’, I wouldn’t call it ‘space’. The universe is not an object ‘in’ space it *is* space (and stars and gasses etc) itself. The typical model system use to describe this is a rubber balloon:
Imagine the entire universe as the surface of a balloon (ok you have to pretend that the universe only has 2 space dimensions rather than the more usual 3, but it makes it easier to imagine!).
So the Big Bang can be thought of like this – Draw spots on the balloon to represent the stars and galaxies and start inflating the balloon. You should notice all the spots start moving away from each other as the balloon/universe expands… It is not that the galaxies are moving around rapidly, but the space/rubber in between them that is expanding.
As for what is it that the universe/balloon is expanding into – As I said I wouldn’t call it ‘space’. Space in this model is the rubbery material that makes the balloon… the rubbery fabric of the balloon doesn’t expand into more rubber.
Essentially, the question ‘what is outside space’ is (for the moment) outside the experience and experimental techniques open to humans… it could be nothing, or something… but it almost certainly isn’t ‘space’, since space is what the universe is made of.
There might be a way of probing what lies ‘outside’ the universe if for example we were to notice the values of what we thought were fundamental constants (for example the G of Newton) started changing. This sort of thing is what might be expected if a ‘neighbouring universe’ moves relative to ours (in the balloon model, this would just be two balloons moving past each other). If this were to happen, you might be able to find out something about the intervening material.