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I heard that "if you go straight long enough, you end up where you were", as analogous to walking on the surface of a globe. Are you saying that evidence again
by daveloyall 10y ago
I heard that "if you go straight long enough, you end up where you were", as analogous to walking on the surface of a globe. Are you saying that evidence against that has surfaced?
- cygx 10y agoThe current assumption of the cosmological standard model is spatial flatness, which is compatible with the observations. In principle, space could still curve back on itself on a large enough scale, but assuming there's no big crunch coming, you'd have to go straight for a longer-than-infinite duration to come back to the place you started from.
- daveloyall 10y agoLonger than infinite? What does a big crunch have to do with it? Maybe I don't know what a big crunch is... I currently think the big crunch is the idea that gravity will eventually coalesce all matter into a single point.
- cygx 10y agoLonger than infinite? In an expanding universe, objects can be separated by a cosmic horizon. Nevertheless, from the comoving perspective, they may very well still move towards each other - but without ever meeting up. However, if you extended conformal time beyond infinity, they would. That's of course not physically possible, so that particular comment was tongue in cheek.