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Don't confuse the "shape" of the universe (eg flat or hyperbolic/open) with the "size" of the universe.Just because the geometry seems (close to) flat, does not mean that it is infinite in extent - it can be flat and finite in size.

If the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper, and infinite in extent.

Quote from: evan_au on 28/03/2013 10:51:59Don't confuse the "shape" of the universe (eg flat or hyperbolic/open) with the "size" of the universe.Just because the geometry seems (close to) flat, does not mean that it is infinite in extent - it can be flat and finite in size.Where did you get that idea from? It's incorrect. I'm quite familiar with the geometry of such universes. I'm curious. Do you think that a straight line that ends at a brick wall? A flat or open universe is infinite in size. See ...sorry, you cannot view external links. To see them, please REGISTER or LOGINQuoteIf the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper, and infinite in extent.And the universe does seem to be flat.

Quote from: Pmb on 28/03/2013 11:01:07Quote from: evan_au on 28/03/2013 10:51:59Don't confuse the "shape" of the universe (eg flat or hyperbolic/open) with the "size" of the universe.Just because the geometry seems (close to) flat, does not mean that it is infinite in extent - it can be flat and finite in size.Where did you get that idea from? It's incorrect. I'm quite familiar with the geometry of such universes. I'm curious. Do you think that a straight line that ends at a brick wall? A flat or open universe is infinite in size. See ...sorry, you cannot view external links. To see them, please REGISTER or LOGINQuoteIf the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper, and infinite in extent.And the universe does seem to be flat.

If the universe is either flat or open it seems to me that there there should be an infinite amount of stars and planets. Given an infinity of them it seems possible that there is a planet identical to Earth out there somewhere just by the law of large numbers. The cool thing about that is that there should be a planet out there with a duplicate of me as king of the world.

Quote from: Pmb on 28/03/2013 01:27:42If the universe is either flat or open it seems to me that there there should be an infinite amount of stars and planets. Given an infinity of them it seems possible that there is a planet identical to Earth out there somewhere just by the law of large numbers. The cool thing about that is that there should be a planet out there with a duplicate of me as king of the world. Maybe,...........but with an infinity of time and space, the universe also has an infinity of choices it can make. And, it's also possible that non of those choices necessarily has to resemble you or your particular life style.