A proposition based on a proposition, but a very interesting one.

[RadarArtillery]

I was reading a book by Professor Hawking, and he proposed that the universe might actually be just like the Earth: Finite in size, but with no bounderies.

That is, one giant sphere where you can never fall off the edge, because if you keep moving in one direction you just end up back where you started.

So, I realized something that that proposal of his implies:

Imagine the sphere as one big 2D circle, and that you are at the zero degree point. Imagine there is something you want to observe at the 90 deegree point. The light only needs to travel a distance of ninety degrees to get to you, but since the universe is a sphere and light is emitted in every direction, it would also travel the remaining 270 degrees around the *other* way and you could observe it from that side too.

The light traveling the 90 degree rout would reach you 75% faster then the light on the 270 degree rout, so the light from the 270 degree rout would be 75% older and be from a point 75% older in the object's history then the light you're observing from the 90 degree rout, which would mean you could look at the same point in space from two different angles and not even realize it, because in one direction it would look like a nebula and the other it would appear to be a star.

This means that if we could discover such an object, and could get light from both angles, and knew the precise rate of expansion of the universe, we could precisely measure the size and age of the entire universe and our position in it relative to the object.

Of course, all of this depends on Hawking's proposal, which is just that right now: A proposal. Not a theory, not even a hypothesis. Still, I thought you all might find this to be interesting.

This is listed in Speculation because of being a proposal based on another proposal. Is this the right place for it?

[Spyman]

The problem is that due to expansion and the age of the universe, we can only see a limited view of the Universe, even if the Universe would be finite like a hypersphere it must be smaller than the observable universe for us get confirmation of this from observation.

 

Currently we don't know how large the Universe is, it could be infinite or so large that our view is only a tiny speck of it.

 

There have been tries to search for duplicate images, which claims a lower bound of a diameter close to the size of the observable universe, but it is disputed:

 

If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe. It is difficult to test this hypothesis experimentally because different images of a galaxy would show different eras in its history, and consequently might appear quite different. Bielewicz et al. claims to establish a lower bound of 27.9 gigaparsecs (91 billion light-years) on the diameter of the last scattering surface (since this is only a lower bound, the paper leaves open the possibility that the whole universe is much larger, even infinite). This value is based on matching-circle analysis of the WMAP 7 year data. This approach has been disputed.

http://en.wikipedia.org/wiki/Observable_universe#The_universe_versus_the_observable_universe

Edited March 11, 2014 by Spyman

[RadarArtillery]

The problem is that due to expansion and the age of the universe, we can only see a limited view of the Universe, even if the Universe would be finite like a hypersphere it must be smaller than the observable universe for us get confirmation of this from observation.

 

Currently we don't know how large the Universe is, it could be infinite or so large that our view is only a tiny speck of it.

 

There have been tries to search for duplicate images, which claims a lower bound of a diameter close to the size of the observable universe, but it is disputed:

 

If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe. It is difficult to test this hypothesis experimentally because different images of a galaxy would show different eras in its history, and consequently might appear quite different. Bielewicz et al. claims to establish a lower bound of 27.9 gigaparsecs (91 billion light-years) on the diameter of the last scattering surface (since this is only a lower bound, the paper leaves open the possibility that the whole universe is much larger, even infinite). This value is based on matching-circle analysis of the WMAP 7 year data. This approach has been disputed.

http://en.wikipedia.org/wiki/Observable_universe#The_universe_versus_the_observable_universe

It's very exciting to hear you mention the possibility of the observable universe being larger then the "Real" universe! I had just thought of that half an hour after I made the post, and had wondered if it had crossed anyone's minds. The idea that one of the protogalaxies we observe might even be our own Milky Way (Certainly not likely that the universe is THAT small, but it's interesting to think about) is simply fascinating, and wonderful fuel for science fiction. I'll certainly look into this issue more, because it's very interesting.

 

As for the first part: I had thought of that, yes. If the universe is larger then the observable universe, it would take a very long time to prove this (Which is why I call it a proposition. Right now, unless the universe is quite small or quite old, we wouldn't be able to test it.) At any rate, though, you must admit that this is a very interesting concept. If it *were* possible