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And WHAT THE HECK is the universe 'expanding into'?
The answers to these questions make me dubious on tiny-human understanding of the nature of reality.
Mechanical Elves, anyone?
Earlier quoted context omitted.
IANAP, but I think so. I vaguely recall that early inflationary expansion was very fast. Like several times the speed of light.
No, not really. One theory is that eventually things will slow and then collapse again. https://en.wikipedia.org/wiki/Big_Crunch Taken to the extreme, this expansion and collapse has been happening over and over again in a cyclical fashion. https://en.wikipedia.org/wiki/Cyclic_model
ELI5: How can the universe be "infinitely big" yet have a measurable "finite age" and the velocity arc of the 'expanding' universe not be some known rate? Such that we can estimate the actual farthest distance. And WHAT THE HECK is the universe 'expanding into'? The answers to these questions make me dubious on tiny-human understanding of the nature of reality. Mechanical Elves, anyone?
Imagine an RTS game on an infinitely large map with fog of war. Sure, there's something out there beyond the fog of war, but we can't see it. (don't try to go too far with this analogy though)
The universe isn't expanding into anything. It just is. This is the key to your misunderstanding I think; the universe isn't expanding through or into some other, extra-dimensional medium. The universe itself is expanding.
Earlier quoted context omitted.
Thank you, went to the comments to learn this. So the universe actually expands pretty fast then! Faster than the speed of light? Strangely...
Space still expands lower than light speed, the moment expansions goes faster night skies will be completely dark because other objects' light won't be able to reach our field of vision. I do not remember how that phenomenon is called.
ELI5: How can the universe be "infinitely big" yet have a measurable "finite age" and the velocity arc of the 'expanding' universe not be some known rate? Such that we can estimate the actual farthest distance. And WHAT THE HECK is the universe 'expanding into'? The answers to these questions make me dubious on tiny-human understanding of the nature of reality. Mechanical Elves, anyone?
I also really wonder what is the universe “inside of”? Like why is spacetime here in the first place?
I agree that our explanation must be impoverished compared to the true nature of nature. It really boggles my mind. I enjoy the public physics lectures scattered around YouTube, but it all still leaves me realizing how limited our understanding is compared to the mundane goings ons of our universe. Our current understanding is that we’ll never communicate with distant galaxies, meaning there’s likely a trillion inhabited worlds full of beings we will never know.
ELI5: How can the universe be "infinitely big" yet have a measurable "finite age" and the velocity arc of the 'expanding' universe not be some known rate? Such that we can estimate the actual farthest distance. And WHAT THE HECK is the universe 'expanding into'? The answers to these questions make me dubious on tiny-human understanding of the nature of reality. Mechanical Elves, anyone?
The entire universe is infinitely large, (we think) but the observable universe is finite, limited by the age of the universe, the speed of light, and the portion of the early universe when space was opaque. (which is what the cosmic microwave background, or CMB is) (note that terminology is confusing; when people use the word "universe" you have to determine base on context whether they're talking about the infinite…
My understanding was that the universe originated as a point, inflated a great deal, then began expanding at a rate that has changed over time. As a result, the universe would be significantly larger than the visible universe, but would have a finite size.
(A finite size, but no boundaries. The universe is a sphere whose circumference is everywhere but whose center is nowhere. Cue Borges music.)
Earlier quoted context omitted.
what is a kvasar
I had to look it up too, it's the German word for Quasar. https://en.wikipedia.org/wiki/Quasar .
(I hear "kvasar" and "cantoom" for quasar and quantum)
Earlier quoted context omitted.
Thank you, went to the comments to learn this. So the universe actually expands pretty fast then! Faster than the speed of light? Strangely...
Space still expands lower than light speed, the moment expansions goes faster night skies will be completely dark because other objects' light won't be able to reach our field of vision. I do not remember how that phenomenon is called.
our observable universe may be around an unobservable area whose light hasn't reached us yet
Earlier quoted context omitted.
The entire universe is infinitely large, (we think) but the observable universe is finite, limited by the age of the universe, the speed of light, and the portion of the early universe when space was opaque. (which is what the cosmic microwave background, or CMB is) (note that terminology is confusing; when people use the word "universe" you have to determine base on context whether they're talking about the infinite…
Infinitely large? My understanding was that the universe originated as a point, inflated a great deal, then began expanding at a rate that has changed over time. As a result, the universe would be significantly larger than the visible universe, but would have a finite size. (A finite size, but no boundaries. The universe is a sphere whose circumference is everywhere but whose center is nowhere. Cue Borges music.)
Rather everything was just closer together. Imagine traveling back in time - you would see galaxies move closer and closer - until everything was super dense and hot - like the center of the sun but everywhere.