2021-07-27, 02:25 AM (ISO 8601)
Re: Properties of void outside the universe*?
Oddly enough, I think the current theory is that you would end up in an overlapping bubble with the same properties (and same big bang)!
Originally Posted by danzibr
The logic goes that when two points are sufficiently far enough apart that the expansion of the universe means they are effectively moving apart faster than the speed of light, then they are no longer in the same universe. However a point half-way between (in so much as that is defined once things are in separate universes) is still in the same universe as both of them.
No - I don't like that theory either (so I have probably badly misunderstood it).
Anyway, if the universe is infinite (as I am told the current theory is) then you could travel 180 B ly and remain in the same universe, but outside the observable bubble. In fact, with distance defined by the universe then no matter how far you travel you cannot leave it by travelling a distance - leaving it would require something else.
Back when I was growing up scientists were rather less sure about the size and "shape" of the universe (one through was that it could be 'closed' - travel far enough in one direction and you get back to the starting point coming from the opposite direction).
As for constant properties, there remain alternative theories for the current universe, particularly for gravity, that mean if you travel far enough in this universe the properties can change! Note, they are minority theories, but although the standard model is getting better and better dark matter and dark energy remain big enough problems that respectable physicists accept that one of the other theories could be more correct (though it is thought to be very unlikely)