All Questions
352
questions
-3
votes
5
answers
213
views
Can some regions of space (independent of size), be completely devoid of matter?
Before answering the question, keep in mind that I am a second year Biology student, with no experience in studying Physics and a very basic understanding of Mathematics. However, I have some ...
- 69
0
votes
1
answer
105
views
If the universe is infinite, would it be homogenous?
I know, that we can't really know the answer to that, but what is the current state of understanding?
We seem to assume that on very large scales, the universe is homogenous. As I understand it, this ...
- 866
5
votes
3
answers
15k
views
Are the claims about repeating states and space in Netflix's "A Trip to Infinity"'s based on real research?
I just watched Netflix's documentary on infinity "A trip to infinity". They have an example where you put an apple in a perfectly sealed box. They make a claim that seems odd to me.
The ...
- 61
2
votes
1
answer
171
views
Particle horizon in an empty universe
So in this thread,
Can space expand with unlimited speed?,
the author Pulsar made amazing diagrams of different horizons and paths for a benchmark model that describes our current universe, and gave a ...
- 161
4
votes
3
answers
2k
views
Will a light come back within finite years?
In this answer Javier said
Imagine the universe was the inside of a ball. We're 3D now, so no one is hiding any dimensions. This ball has a border, except it's not really a border. You should think ...
- 405
0
votes
2
answers
91
views
What is there at a point the universe hasn't expanded past yet? [duplicate]
(Please don't mark as a duplicate)
If the universe is constantly expanding that means that there is a point the univese hasn't expanded past, with that what would be past that point? This isn't about ...
- 11
0
votes
0
answers
19
views
Dark matter and un-smoothness in spacetime [duplicate]
Since dark matter currently is only observable with its gravitational effects and nothing else can we theorize that dark matter is only non-smoothness in spacetime that has been there from the Big ...
0
votes
1
answer
91
views
If I moved in a straight line forever, would I hit something?
Say you could move infinitely fast/gravity doesn't affect you. You move in a straight line. Do you hit anything, like stars or black holes? Not talking about cosmic dust.
- 178
2
votes
0
answers
85
views
Could the universe be a 4-ball?
I recently thought of the idea that the universe could be an infinite 4-ball. The Big Bang would be its centre, and time would be outward from its centre (one layer would be one point in time). I ...
user334229
2
votes
2
answers
178
views
Space-time continuum expansion
I still don't understand how the expansion of the universe works.
If the universe is made up of an infinite number of points that make up space-time, then how can space expand or stretch. Common sense ...
- 343
-1
votes
2
answers
169
views
Can space only be infinite? [closed]
I have read before that if you could just go fast enough, as a thought experiment, and you move in a straight line, in any direction, that you eventually might reach the spot from which you started. I ...
- 11
1
vote
3
answers
136
views
Is the solar system sitting in the centre of curved spacetime and if so, are we viewing the rest of the universe from inside that "bubble"?
I read an article about a huge bubble being discovered in which the solar system sits bang in the middle. It got me thinking about the curvature of spacetime. The bubble was created by several ...
3
votes
2
answers
1k
views
Space is flat but spacetime is curved?
In the picture below a triangle has been drawn on a spherical shaped object. The angles add up to 67+48+73=188 degrees. Since the surface of earth is also almost spherical therefore an experiment can ...
- 717
-2
votes
1
answer
260
views
IF heat was the absence of cold, how would that change physics [closed]
Back in high school, I had an argument with my physical science teacher. She said cold is the absence of heat. I asked why it couldn't be the other way around. She simply stated that was not possible. ...
0
votes
3
answers
242
views
Is there evidence for the existence of time? And what's eternalism (block universe)? [closed]
I have been told that: "time is an illusion. Rather than a chronological progression of events, all events occur simultaneously in space, and so right now, dinosaurs exist, WW2 just ended, you're ...
- 133