All Questions
Tagged with cosmology special-relativity
127
questions
4
votes
6
answers
789
views
Why are distant galaxies not actually tiny bits of matter?
Distant galaxies are said to be moving away from the Milky Way (and us) at speeds approaching the speed of light. Since Special Relativity tells us that any object moving away from us at a velocity of ...
- 59
19
votes
2
answers
1k
views
Limitations on how far one can travel in the universe
Someone once incorrectly told me that, given the speed of light is the speed limit of the universe, aliens would have to live for hundreds of years if they are to travel distances of hundreds of light ...
- 5,611
7
votes
2
answers
4k
views
Is 2.5x speed of light possible between two objects?
These news are in Finnish:
http://www.hs.fi/ulkomaat/Kaukaisin+havaittu+galaksi+et%C3%A4%C3%A4ntyy+maasta+valoa+nopeammin/a1305618680897
The main excerpt is:
"Distant galaxy moves away from us as ...
- 225
1
vote
2
answers
503
views
Causal reconnection
Can causally disconnected regions join up again? For example the universe is expanding faster than light creating cosmological horizon, but what if something causes the expansion to slow down and ...
- 859
0
votes
1
answer
639
views
Does the Earth's revolution around the Sun affect radioactive decay?
Premises:
The radioactivity is either hastened or slowed inside a fast moving aircraft.
Speed of fastest aircraft: 3,529.6 km/h.
The earth's revolution is: 107278.87 km/h.
The earth's ...
- 123
3
votes
1
answer
377
views
Violation of Lorentz symmetry on cosmological distances
This question is about the domain of validity of Lorentz symmetry.
As far as I know, general relativity is a generalization of special relativity. Does that mean that Lorentz symmetry is violated on ...
- 17.1k
12
votes
6
answers
2k
views
How large is the universe?
We know that the age of the universe (or, at least the time since the Big Bang) is roughly 13.75 billion years. I have heard that the size of the universe is much larger than what we can see, in other ...
- 3,439