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Author Topic: Is there no end to space?  (Read 9991 times)

Offline Joe L. Ogan

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Is there no end to space?
« on: 07/12/2012 22:02:50 »
Is there no end to space?  Einstein had a formula for calculating space but it does not answer my question.  It appears to me that every thing must have an end but I can find no answer to my question.  Thanks for comments.  Joe L. Ogan


 

Offline Don_1

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Re: Is there no end to space?
« Reply #1 on: 07/12/2012 23:06:19 »
"Is there no end to space?"

I don't think there is. All the theorising of space bending in on itself, doughnuts, figure of 8 etc. still leaves the question of what is outside of this imaginary universal 'shape'. To me they still leave the possibility of an edge or boundary.

Until someone can prove otherwise I shall continue to consider the universe to be in 3 parts. Part 1, the mass, part 2, the space between the mass and part 3, the void into which the mass and space are expanding.
 

Offline evan_au

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Re: Is there no end to space?
« Reply #2 on: 08/12/2012 06:48:19 »
Assuming you are talking about an edge of our "Observable Universe", ie the part of space you could visit if you had a hypothetical spaceship that could travel at > 99.99% of the speed of light, would you reach point beyond which all is empty?

This answer can be addressed in several parts:
  • Is our universe infinite in "width"? If so, then you could travel forever, and never reach a boundary. (Most recent cosmologists seem to seem to suggest that our universe has a finite width, of around 14 billion light years.)
  • Does our universe have a "boundary"/"edge"? With your spaceship traveling slightly slower than light, you can never overtake all the matter that started traveling before you, so you will always see matter beyond you on all sides. So there might be a boundary, but you will never reach it.
  • But what if you had an even more hypothetical spaceship that could travel significantly faster than light (like 1 billion light-years per minute), would you run into such a boundary? This is where it gets weird, because most recent cosmologists suggest that our space expands to contain all the matter that there is. Opinions differ, but some suggest that you could, after a quarter of an hour or so, end up back at Earth!
  • As far as we know, you can't escape intact from a black hole, once you have passed the event horizon. Cosmologists don't like to talk about it too often, but the Big Bang Theory suggests that "Our whole universe was in a hot dense state" (http://www.lyricstime.com/barenaked-ladies-the-big-bang-theory-lyrics.html) in which case it started as a black hole, and we are inside it. If so, you can't get out! 

If you are talking about the also-hypothetical Multiverse, which contains parts we cannot even hypothetically visit (with our current knowledge/technology), I would say that this is beyond our current boundary.
 

Offline JP

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Re: Is there no end to space?
« Reply #3 on: 09/12/2012 17:47:08 »
Is our universe infinite in "width"? If so, then you could travel forever, and never reach a boundary. (Most recent cosmologists seem to seem to suggest that our universe has a finite width, of around 14 billion light years.)

Do you mean 14 gigaparsecs, which is roughly the size of the observable universe?  The observable universe is actually ~42 billion light years in size.  It's 14 billion years old, but has been accelerating in its expansion so we can see light from stars 42 billion light years away.  I used to get this wrong, too, until someone pointed out the error.  There's a nice explanation on Wikipedia here:
http://en.wikipedia.org/wiki/Observable_universe#Misconceptions

That's also the size of the observable universe.  It's possible (and quite likely) there's more to the universe than that.  It's just that the distance between us and anything beyond that edge is growing at faster than the speed of light due to the expansion of the universe, so we'll probably never get to see it (unless we figure out faster than light travel). 
 

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Re: Is there no end to space?
« Reply #3 on: 09/12/2012 17:47:08 »

 

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