81–90 of 231 posts
Earlier quoted context omitted.
The first one means the space time metric changes
Is it possible that the universe stays the same size and everything within it shrinks?
The standard way is probably much easier to reason about.
Earlier quoted context omitted.
The first one means the space time metric changes
Is it possible that the universe stays the same size and everything within it shrinks?
But AFAIU, there is no edge to the universe with an unknown something beyond the barrier. Space is not an expanding balloon inside a bigger balloon. Ie, there is no space beyond space.
Not that i'm truly able to wrap my head around it, but at the moment of the big bang, time and space themselves exploded into existence.
What came first, the photon or the electron? Can a photon be emitted without a change in energy state? I’m new here, so instead of answering questions is the protocol just to downvote?
Earlier quoted context omitted.
All the evidence suggests that Big Bang did not happen at one identifiable point. Instead it happened everywhere simultaneously. So there is no place in our universe "very far away from the Big Bang".
Not the above poster, but I want to understand. I have half-understood thoughts that conflict with each other. Any help showing where I misunderstand is appreciated, but this is probably a failure of my brain to be able to cope. * All space was contained in the big bang, so "everywhere simultaneously" makes sense from that perspective. * ...but the idea that space is expanding implies an outer "edge" (, which doesn't…
No, it doesn't.
For example: consider an infinite number of marbles in an infinitely long line, all of them are touching each other.
Now, get an infinite number of helpers stationed along the infinitely long line, and have them all move the marbles in front of them to the right and stagger them out in the process, so that there's now an inch between each marble.
You now have an infinite number of marbles an infinitely long line, but it's a longer line than it started out, because there's now an inch between all the marbles.
I think, by Occam's Razor, the most likely explanation is that there's a skybox surrounding the solar system that Voyager 1 may run into any day now, like Truman Burbank at the end of The Truman Show. It seems to be a more parsimonious explanation of the available facts that we're looking at the result of a super duper planatarium projector, as opposed to an actual vast and frequently inexplicable universe.
Earlier quoted context omitted.
All the evidence suggests that Big Bang did not happen at one identifiable point. Instead it happened everywhere simultaneously. So there is no place in our universe "very far away from the Big Bang".
Not the above poster, but I want to understand. I have half-understood thoughts that conflict with each other. Any help showing where I misunderstand is appreciated, but this is probably a failure of my brain to be able to cope. * All space was contained in the big bang, so "everywhere simultaneously" makes sense from that perspective. * ...but the idea that space is expanding implies an outer "edge" (, which doesn't…
Space expension just means that the metric used to measure distance increases with time. It doesn't imply a border.
Consider the function equivalent to the Euclidian distance on a line : d(x1,x2) = sqrt((x2-x1)^2)
Now, you can consider the function : d2(x1,x2,y) = y * d(x1,x2)
If you view x1 and x2 as positions on one axis and y as a position on the other one, you can think of d2 as the distance between x1 and x2 expanding as you go higher in the plane.
Space expansion works in the same way but y is actually time.
Earlier quoted context omitted.
Correct me if any of the following is wrong, though: when we say the universe is expanding, we mean that matter is spreading out. The further apart the matter is, the faster it's spreading out. If we back-trace the position of stars, they all coincide at roughly the same point in time and space. This led us to believe that at some point in time all of this matter was together, incredibly dense, and in a very "hot", h…
Perhaps a big bang that's 'just' an explosion in spacetime, rather than of spacetime, would not work with known physics because that concentration of that much matter would be a black hole? Until now, I never thought to ask anyone.
https://upload.wikimedia.org/wikipedia/commons/c/c7/Space_Ex...
You can see that from any given point:
1. Every other point is moving away from you
2. Points further away are moving away at a faster rate
This could only work out if space were expanding. If it were an explosion instead, everything would be moving away from a fixed central point.
This reminds me of Iain Bank’s Excession. Great book, strongly recommend it.
GN-z11 is a galaxy that's 32 billion light years away. Here's the note from wikipedia: At first glance, the distance of 32 billion light-years (9.8 billion parsecs) might seem impossibly far away in a Universe that is only 13.8 billion (short scale) years old, where a light-year is the distance light travels in a year, and where nothing can travel faster than the speed of light. However, because of the expansion of t…
Also, despite the age of the universe (13.8B years), the diameter of the observable universe is 93 billion light years. That's because the universe expanded (and probably still is expanding) faster than light.
Earlier quoted context omitted.
Correct me if any of the following is wrong, though: when we say the universe is expanding, we mean that matter is spreading out. The further apart the matter is, the faster it's spreading out. If we back-trace the position of stars, they all coincide at roughly the same point in time and space. This led us to believe that at some point in time all of this matter was together, incredibly dense, and in a very "hot", h…
> when we say the universe is expanding, we mean that matter is spreading out It's been a while, but I recall reading in a book that's actually the space between everything that's expanding, much like you state in your second paragraph. For example, if you blow up a balloon, two points on it will appear to be moving apart from each other even though they're stationary. I believe this Forbes article is in agreement: h…
But that's also somewhat misleading as it gives the impression that it's just interstellar space (reinforcing the non-scientific connotation of space) that inflates. At some point even atoms may not be able to hold together. See https://en.wikipedia.org/wiki/Big_Rip Whether the Big Rip is true or not, it's useful as a supplemental illustration.
