RE: IFC S02R01: The Disappearing Universe
redshifting and blue shifting
In many ways, we are already familiar with a classical version of it. Doppler shifting... when sound waves (like from a fast moving car), changes in pitch (wavelength/frequency) due to lengthening of the distance between emitted wave peaks. For light (EM waves), there is an element of this Doppler shifting if things are moving fast towards (blue) or away from us (red).
However, for further away objects, this is overwhelmed by the (red)-shifting due to the expansion of the space in between. This is the more unfamiliar concept... as it is caused by the space in between expanding, and is not a property of the motions of the objects involved.
If the universe is expanding, what is on the other side of that expansion?
Technically, the problem with that question is more to do with our limited experience of reality and the Universe. We have to use analogies to get our heads around the concepts... .which neccessarily means that we assume that we have to expand INTO something... because that is the way we normally perceive expansion. However, for this, the expansion is of the Space-Time metric, which isn't quite the same thing as the expansion that we experience with everyday objects! It is more akin to your ruler which you measure things with expanding (changing size between the centimetre pips)?
Of course, this interpretation could still be wrong... but it is the prevailing one. It is more that there currently is no need to postulate a "thing" to expand into! So, it is more of the Occam's Razer solution at the moment...
It's an interesting question indeed.
Because saying that the universe is expanding INTO something would be illogical as that "something" is already a part of that very universe. The universe doesn't have any rigid boundaries. It includes everything there is.
It "expanding" might be the result of something called dark energy which is a theory first proposed by Einstein. In simple words, it the opposing force of gravity. While gravity pulls in, dark energy pushes out. So in theory, if gravity were the dominant force in our universe, the universe would contract.
Correct me if I'm wrong.
Yes, although dark energy is the place holder name until they figure out exactly what is causing the expansion.
Thanks for expanding, I'm not familiar with that technology very much so it's still a bit fuzzy for me, but I think I get it in a sort of general sense!
Interesting explanation yet regardless of whether things are expanding within a set limit or more than that it still begs the question, what's outside of that? And I've seen a good amount of theories put out there yet I just don't think anyone alive probably knows for sure since it's beyond our ability to observe. We may never be able to know? It really does make one wonder though! Like.. Is there just an infinite amount of empty space outside the perceivable universe? Or..?? Lol. Fun to think about whatever the case.
Perhaps though there's no need to theorize about many things, yet we still do and I think a lot of richness in life comes from that. :)
LOL, was that intentional?
I think I put that badly... there is no need to add extra, unless you are trying to explain something that currently has no explaination! In which case, the extra postulations need to serve up some falsifiable predictions that build upon the known knowns!
However, interesting to think about... but I suspect (if it is needed) it is something that would be so far out of our realm of experience to be completely unimaginable.
Not in a pun sort of sense, no. Lol.. It should have been though! It's perfect for the subject.
Ah. Understood, though I think it's great for people of all levels to just theorize in general even if they aren't adding anything new that hasn't been theorized before officially. It's good to encourage people to think and talk about things in general I think.
Indeed.. And yeah, probably.. It's a crazy universe we live in! Sorry for the super late response by the way, as you know I can get a bit delayed with my responses and it can take a while! Sometimes I never get to them but today I found some time to go back and respond to most of my messages.