well, i think its best to remember that nothing outside of the universe exists. The universe is everything so nothing exists outside of itself. The expansion of the universe can simply be viewed as the stretching of space. since space is everything, it doesn't stretch into anything but itself, this highlights two propositions (1) the universe is infinite
The
idea that space is expanding is based on Einstein’s General Theory of
Relativity, and backed by Hubble’s observation of Redshift. The General Theory of Relativity says space
has a shape, if it has a shape then it isn’t infinite. The Standard Model of Cosmology presupposes
a Big Bang universe expanding from a point in time and space, because you can’t
traverse and infinite either spatially or temporally, both the Standard Model
of Cosmology and the General Theory of Relativity explicitly deny the proposition
that the universe is infinite. If it was infinite, it couldn’t be expanding, it’s
also logically and cognitively inconceivable that an actual infinity could
exist. If an actual infinity did exist
we could not confirm it through observation because there would be no way to
measure it. If I did exist, there is no
way for us to know it.
Of course, a cyclical model could be considered infinite, but none of our scientific models
are cyclical.
or (2) laps back on itself. In case 1, it could be described as Somewhat like if we bounce on a trampoline it spreads out and closes back in depending on the force put upon the trampoline, but the amount of material on the trampoline never increases or decreases. All that increases and decreases is how stretched out whatever is already there is. In this same sense the universe is never stretching or going into anything new, but stretching what is already there, like the trampoline. It may be that space simply is literally bending into itself.
The
problem I see with option 2 is that if in fact space itself is expanding then by
definition, the distance between all the objects in space are increasing, but
if it laps back on itself, wouldn’t that entail the distance between at least
some objects decreasing, which would mean space in that region would be
contracting.
If the universe is indeed infinite, then the simple answer is that the universe doesn't have anything to expand into. A good analogy can be made with math. Imagine you have a list of numbers, 1,2,3,etc all the way up to infinity. Then you multiply every number in this list by 2, so that you now have 2,4,6 etc all the way up to infinity. The distance between the numbers in your list has "stretched" (it is now 2 instead of 1), but can you really say that the total extent of all your numbers has expanded? probably not, because in the end it all leads to infinity again anyways. So there is still stretching but you still end up with the same total.
That’s the problem with the concept of infinity, I don’t
think it can be said to be a valid mathematical concept, at least in the sense
that when you apply mathematics to it, you get logically incoherent results. One
of many examples is algebraic, infinity + infinity = infinity, subtract
infinity from both sides of the equation and you get infinity = zero, which is nonsensical. It’s a useful concept for referring to a
cyclical function, but it really can’t be considered a number or even a valid
mathematical object.
Modern science produces a lot of mathematical infinities
but I tend to think they represent places where the mathematical formulas break
down. When scientific equations introduce infinities and zero divisors it does
not speak to what is possible in the real world as much as it speaks to the
limitations of our mathematical equations to adequately represent reality.
I suppose the only way that infinities could be actual would be “dimensionally”
speaking. If the reality that we
experience, that we are capable of experiencing, is a lower level,
four-dimensional aspect of a far greater reality that we are incapable of even
fathoming, certainly more than we can adequately express with the limitations
inherent in the tool of mathematics, then I suppose that would entail the
possibility of actual infinities, but that would transcend our science and our mathematics. (that plus many of those words would be a Pavlovian trigger for all of our spiritual detractors to lose it and throw a tantrum lol).
