Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Joe L. Ogan on 22/11/2009 17:57:43

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: Joe L. Ogan on 22/11/2009 17:57:43

Does anyone really know whether space is finite or infinite?  Besides, in space, there may be another description for existence.  Just a thought.  Joe L. Ogan

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: Mr. Scientist on 23/11/2009 00:24:46

We know space is expanding and now acclerating from some [finite] point in time. Now, at this general periodic galactic time (or asymptotic time) we can argue that spacetime is accelerating without recourse, and thus must imply it is infinite in size, because logically, the size of the universe now, was not the same as it is after. This is a process which has been proposed to have occured somewhere between 10,000-15 million years ago.

So space has a finite past, but predictably an infinite future, making it one large infinite streak in itelf.

Could you clarify this question please:
Besides, in space, there may be another description for existence.

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: Joe L. Ogan on 23/11/2009 00:34:56

Please let me clarify what I meant about space having a different definition than finite or infinite.  Since my limited human brain knows only these two definitions, I can only conjecture it might be something in between or something that could not even be conceived by my limited human brain.  I hope this helps.  Joe L. Ogan 

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: Mr. Scientist on 23/11/2009 02:21:19

No, i am sorry - it doesn't.

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: LeeE on 23/11/2009 07:46:12

It's an interesting question Joe, and the answer depends on how you look at it.

Space seems to be unbounded, which is to say that we're not aware of any intrinsic limits to it, so in this respect it appears to be infinite, or at least potentially so.  However, if you go along with the idea of the Big Bang, then the universe clearly appears to be finite in the time dimension, for it has a finite age.

The thing is though, that we cannot really separate space and time from each other and need to think of them as a unified space-time environment, which is expanding both in space and in time: the galaxies all seem to be receding from each other due to the spatial expansion of the universe, and at the same time we also seem to be constantly moving into the future i.e. into new time.

When thinking about space-time though, you need to be aware of the limitations of having a view point that is restricted to a particular number of dimensions, for there is infinite n-1 dimensional space within a finite n-dimensional environment e.g. there is enough space for an infinitely long 1-dimensional line within a finite 2-dimensional area.  This implies then, that there would seem to be scope for infinite 3-dimensional space-time within our 4-dimensional space-time environment, which is currently finite in the time dimension.  However, while the universe appears to currently be finite in the time dimension, the time dimension appears to be unbounded, just like space, which in turn rather suggests that our 4-dimensional space-time may exist within a higher order 5-dimensional space-time environment.

Title: Does not being able to prove that space is finite, necessarily, prove that it i?
Post by: variationz on 26/11/2009 04:27:53

Space is finite in nature...

and here are the answers for your questions...

http://www.thenakedscientists.com/forum/index.php?topic=26911.0

I hope you get them right!