All Questions
Tagged with general-relativity time-dilation
429
questions
104
votes
2
answers
8k
views
Is there such thing as imaginary time dilation?
When I was doing research on General Relativity, I found Einstein's equation for Gravitational Time Dilation. I discovered that when you plugged in a large enough value for $M$ (around $10^{19}$ ...
- 3,967
77
votes
9
answers
19k
views
If the speed of light is constant, why can't it escape a black hole?
When speed is the path traveled in a given time and the path is constant, as it is for $c$, why can't light escape a black hole?
It may take a long time to happen but shouldn't there be some light ...
- 1,289
38
votes
4
answers
7k
views
Are today's chip scale atomic clocks accurate enough to conduct my own test of time dilation?
Regarding the Symmetricom SA.45s Quantum™ Chip Scale Atomic Clock, is it accurate enough to test time dilation if I place one at sea level, and one on a mountain? It's accurate to 3.0⋅10−10 per month....
- 521
34
votes
6
answers
10k
views
Is gravitational time dilation different from other forms of time dilation?
Is gravitational time dilation caused by gravity, or is it an effect of the inertial force caused by gravity?
Is gravitational time dilation fundamentally different from time dilation due to ...
- 663
32
votes
4
answers
9k
views
Why isn't the center of the galaxy "younger" than the outer parts?
I understand that time is relative for all but as I understand it, time flows at a slower rate for objects that are either moving faster or objects that are near larger masses than for those that are ...
- 469
27
votes
8
answers
3k
views
Can a ultracentrifuge be used to test general relativity?
With today's ultracentrifuge technology, they can spin so fast that the sample can be subjected to accelerations of up to 2 millions Gs. That is equivalent to two solar masses. Has someone tried to ...
- 370
25
votes
3
answers
8k
views
Why don't we put satellites into an orbit where there is (almost) no time dilation/contraction compared to Earth's surface?
Consider:
On this image, if I understand correctly, the time dilation diagram is shown depending on the height for circular orbits. First in low orbit, time slows down relative to the surface due to ...
18
votes
5
answers
7k
views
Understanding Time Dilation at the Event Horizon
I was recently reading about the event horizon of black holes and came across the fact that, to a "stationary" observer, it takes forever for someone to fall into a black hole. The sources claim that ...
- 954
17
votes
1
answer
5k
views
What is the maximum time dilation factor when orbiting a rotating black hole?
Suppose one spaceship is stably orbiting a rotating black hole and another is far away from the black hole. What is the maximum time dilation factor between the two ships? Can it be made arbitrarily ...
- 53.2k
16
votes
4
answers
4k
views
How long is a second on the moon?
The Office of Science and Technology Policy, part of the government of the United States of America, issued this statement outlining the need for a Lunar Standard Time (LST) standard. They state:
For ...
- 4,030
16
votes
3
answers
2k
views
Time dilation effects at the center of a binary black hole system
Imagine two identical black holes in a circular orbit, and Alice is smack-dab in the middle of the system (at the barycenter). Bob is at infinity.
Let's assume that Alice and Bob are stationary ...
- 779
16
votes
2
answers
1k
views
Time Dilation inside a hollow shell
Assuming I have a hollow shell with total mass $M$ and radius $r$.
On the surface, the gravitational time dilation would be
$$\tau=t \cdot \sqrt{1-\frac{v_{esc}^2}{c^2}}$$
where
$$v_{esc} = \sqrt{\...
- 12.4k
15
votes
1
answer
2k
views
Movie Interstellar - Question about Escape Velocity
The movie Interstellar shows people on a water planet where time is dilated so much that 1 hour is equal to 7 years back on Earth. Even though they lift off from Earth using a Saturn-V two stage ...
user32023
13
votes
9
answers
3k
views
How does gravitational time dilation affect matter?
Einstein successfully melded together space and time into one entity called spacetime in his General relativity theory and gave us further insight into how matter affects spacetime.
John Wheeler said “...
- 719
12
votes
2
answers
2k
views
How do we know the assumptions of the Schwarzschild solution are valid?
The Wikipedia article on the derivation of the Schwarzschild solution (https://en.wikipedia.org/wiki/Derivation_of_the_Schwarzschild_solution) lists 4 assumptions. The second of which is:
A static ...
- 1,011