The tag has no wiki summary.

learn more… | top users | synonyms

4
votes
3answers
280 views

A sees B's clock running slow and B sees A's clock running slow? [duplicate]

This paradox is very common it seems, in which A sees B's clock running slow and B sees A's clock running slow. Here is the question a little more concretely. Let's say B flies by A's spaceship. If ...
0
votes
2answers
33 views

What is the correct formula for gravitational time dilation for a satellite in a circular orbit?

In the Wikipedia article on Gravitational Time Dilation I see two formulae for the gravitational time dilation. One contains $\sqrt{1 - r_0/r}$ but the other $\sqrt{1 - 1.5 r_0/r}$. What formula ...
1
vote
0answers
50 views

General Relativity: impact of acceleration on time, experimental setup

In What is relativity by Jeffrey Bennett (Amazon link), the author explains how acceleration/gravity impact time and causes time dilation. For this he takes an example of an accelerating space-ship ...
1
vote
1answer
72 views

Turning off point for 1g acceleration

Let's say I am on a ship accelerating with 1g. I want to keep the engine running for half a year ( to an observer from my point of origin ) but due to time dilation it would have to be sooner than ...
44
votes
11answers
3k views

Why isn't length contraction permanent even though time dilation is?

It's my understanding that when something is going near the speed of light in reference to an observer, time dilation occurs and time goes slower for that fast-moving object. However, when that ...
0
votes
2answers
78 views

Is it correct that there is time dilation and time contraction in the same reference frame?

I have played a bit with spacetime diagrams and Lorentz transformation and can see time dilation, length contraction and the relativity of "at the same time". Classical: ...
0
votes
1answer
60 views

How are these types of time dilation related?

How are these two phenomena related (if at all): 1. Gravitation slowing down time 2. High speed slowing down time
1
vote
1answer
123 views

Time dilation - Earth & Jupiter [duplicate]

I have this doubt after watching Interstellar movie :) Lets assume I am in Jupiter. (I know it is a gas planet, full of hydrogen and helium, has extreme pressure etc. Lets please ignore those facts ...
0
votes
2answers
46 views

For a rocket travelling to a planet, which reference frame measures the dilated time?

I'm getting into some confusion with relativity. Consider a rocket and the Earth as two observers, and then the rocket travels to a distant star. Is the proper time taken measured in the frame of ...
0
votes
0answers
28 views

Relative time dilation in Schwarzschild metric

Let's say we use the Schwarzschild metric to model the curved spacetime around a planet of mass $M$ and radius $R_0$. One clock $A$ is hovering at distance $R_A$ > $R_0$ with the help of rockets, a ...
0
votes
0answers
148 views

Time Dilation Geometry

I was recently exploring time dilation from Gravity and from velocity and I came up with an interesting derivation that I have not seen before. I was wondering if there is a paper published showing ...
3
votes
3answers
127 views

Time slowed by gravity

If time moves more slowly on Earth (due to our proximity to a gravitational body) than for someone orbiting Earth in a spaceship, yet the opposite occurs in the frequently cited "twin paradox" of the ...
0
votes
1answer
38 views

Viewing a Time-Dilated Space

I'm fascinated by space and physics but not exactly well-versed in them, so I'll try to keep this question as simple as possible. Imagine a person acting as an observer in a room with two large ...
0
votes
1answer
29 views

Question about time dilation and relativity [duplicate]

Take this scenario for example: I am on a rocket ship that will take a trip into space and back at 90% the speed of light. And my friend "Bob" stays on Earth. As soon as I leave Bob and I both start ...
2
votes
1answer
122 views

Can I practically demonstrate Gravitational Time Dilation by spinning a wheel very fast? [duplicate]

In an attempt to demonstrate gravitational time dilation, I was curious if it were practical to mount a clock to a fast spinning wheel, with the centripetal acceleration of the wheel being equivalent ...
4
votes
5answers
168 views

Confusion about Length Contraction (ex in Muon decay)

I am a bit confused about the implications of length contractions; For example, in the muon decay problem, we assume that the distance between the muon and the earth is contracted only in the frame ...
2
votes
0answers
32 views

Can a gravitational wave produce oscillating time dilation?

I was reading about gravitational waves and about laser based detectors. I also read this. As mentioned in the answer, when ever there is a deformation in spacetime, doesn't it also create a minute ...
0
votes
0answers
26 views

Gravity at event horizon [duplicate]

To find the gravity at Schwarzschild radius of a black hole, I used the below equations. Assuming escape velocity at event horizon is speed of light c and M is the mass of the black hole $$ v_e = ...
1
vote
0answers
44 views

Do time dilation tests prove that it exists or that atomic clocks are faulty? [duplicate]

Are the experiments that prove that time dilation exists, actually proving that an atomic clocks ability to keep time is affected by gravity/acceleration? How do we know 100% that that is not the ...
0
votes
0answers
39 views

Is time dilation a mechanical slowdown only? [duplicate]

I've recently read about the time dilation occurs at very high speeds. But I'm really wondering if it is just a mechanical slowdown of the clock only? What if we use clocks that does not use moving ...
6
votes
5answers
252 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 ...
1
vote
2answers
68 views

Length of Day and year on massive Earth

Say, a planet has the same orbital periods as Earth (365 days in a year, 24 hours in a day, etc. with respect to Earth-bound clocks), but the planet has double the mass. So, time must pass more slowly ...
5
votes
1answer
361 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 ...
1
vote
2answers
87 views

How is strong time dilation consistent with weak tidal forces?

Nolan's latest film, Interstellar, takes pains to explain to lay audience members that the passage of time slows in the presence of strong gravitational fields (as per Einstein's theory of General ...
1
vote
2answers
55 views

Time Dilation Experiment [duplicate]

I am currently thinking of doing an experiment for science fair involving time dilation which will use the equations for both time dilation based off of speed and for gravitational dilation to ...
0
votes
1answer
73 views

Applying Lorentz Transformations and Time Dilation

My question is based on a popular question, usually posed in introductory courses on the special theory of relativity. Two rockets are on a collision course. Rocket 1 is traveling at the speed ...
2
votes
2answers
900 views

How long is a second in zero gravity?

General relatively predicts that gravity creates time dilation and a relatively slower passage of time for the observer experiencing larger acceleration. For an observer experiencing zero ...
2
votes
1answer
63 views

Does space-time cause time dilation at relativistic speeds?

I'm trying to understand the concept of the space-time continuum and it's effect on time dilation but am having difficulty with parts of it. To me there seems to be two separate components to time ...
2
votes
4answers
161 views

If Julian Barbour is Correct, is the Speed of Light Special?

According to this article in Discover Magazine, Albert Einstein's Theory of Relativity is wrong, because it didn't fully live up to the ideas of Einstein's idol, Ernst Mach. Mach proposed a truly ...
2
votes
2answers
125 views

Does space between objects contract?

I had a question, let us assume a coordinate system where there is 2 objects moving at relativistic speeds (at same velocity) for the observer therefore the observer will observe the length ...
2
votes
3answers
163 views

Can length contraction really be derived from time dilation? Does speed equal speed?

I am referring to Wikipedia: "Length contraction can also be derived from time dilation." with the following proof which seems to be the result of a circular reasoning. The proof uses only one and ...
7
votes
1answer
568 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 ...
0
votes
0answers
67 views

Is it OK to see time dilation and (relativistic) mass increase as phenomena that avoid $c$ being reached? And how about length contraction?

I think I have been exposed since years ago to this line of reasoning: if $ v\to c $, then $ \Delta t \to \infty $. As $\displaystyle v=\frac{\Delta s}{\Delta t} $, it's like a natural reaction to ...
0
votes
2answers
53 views

Time dilation in outer space vs in a gravitational field? [duplicate]

I have been wondering how could aging process differ for a person moving close to velocity of light or for a person close to a very strong gravitational field compared to a person who is in a slow ...
2
votes
0answers
58 views

Falling into the black hole: a picture from the infinite distance [duplicate]

This question was bugging me for many years. Here it was argued that it would take an infinite time for somebody (suppose, an astronaut) to fall into the black hole, given that it is not his time, but ...
0
votes
1answer
52 views

Transverse doppler effect in light

In most books to explain transverse Doppler effect the following example is given: Consider a source that emits flashes at frequency f0 (in its own frame), while moving across your field of vision at ...
1
vote
2answers
606 views

Gravitational time dilation caused by a galaxy, and by

In a word, if you are sitting on the Earth, if I'm not mistaken you are experiencing Time Dilation compared to being in deep solar system space. Due to the mass of the Earth. However. We're all ...
2
votes
3answers
143 views

Problem with understanding time dilation (moving clocks can run faster?)

I ran into a serious problem with the Lorentz transformation and time dilation. In the standard configuration you have one observer S and another one S' with their x-axis aligned. I assume S to be at ...
3
votes
2answers
156 views

Does this proof for time dilation ignore length contraction?

A simple proof for time dilation can be found here http://en.wikipedia.org/wiki/Time_dilation#Simple_inference_of_time_dilation_due_to_relative_velocity What I am confused about is that when the ...
0
votes
0answers
40 views

Relativistic Doppler Effect and the Sagnac effect

What I think I know about the Sagnac effect can be found here. It occurs to me that the equations for calculating the time do not take the Doppler effect into account. I'm familiar with the very ...
-2
votes
1answer
102 views

Why is it legitimate to only observe motion, but call it time, such that concepts like “the relativity of simultaneity” are seen as possibly genuine? [duplicate]

My question is asking for evaluation of a new concept or paradigm within the framework of the current mainstream physics understanding of Relativity. Specifically, that concept or paradigm being that, ...
0
votes
3answers
75 views

why does a change in velocity cause length contraction, mass gain and the slow down of time? [duplicate]

How did the universe 'know' to do that? Or is there an intuitive explanation for it?
0
votes
2answers
41 views

Time Dilation, Multiple Earth's?

I was reading about time dilation and suddenly a question raised in my mind. (This might be a misconception but please do correct me if I am wrong) I read that if we travel near to the speed of ...
1
vote
4answers
67 views

Time dilation if earth was stationary

Being on earth, we are constantly flying through space at incredible speeds. We revolve around a sun in a system that revolves around the center of the galaxy that is hurling itself through space. ...
0
votes
0answers
38 views

How can the clock c1 be synchronized with the clock c2?

A clock c1 is situated at a distance $L$ from an observer carrying a clock c1. How can the clock c1 be synchronized with the clock c2?
-1
votes
1answer
101 views

How fast must Nadia travel so that she is the same biological age as her twin upon returning to Earth? [closed]

Two twins, Nadia and Aidan, decide to have an adventure when they turn 21. Aidan chooses to travel to a distant star 10 light years away at a speed of 0.8c. Nadia decides to travel to a closer ...
0
votes
2answers
93 views

Time dilation confusion

I'm just starting to learn about special relativity, and I'm a little bit confused about something. Take the example of an observer in $S$ on the ground observing a train move at constant velocity $v$ ...
0
votes
1answer
207 views

Time Dilation Problem [closed]

I'm having some trouble using the time dilation formula. Say an astronaut leaves Earth for 10 years, at 0.85c. How much time has passed according to an observer on Earth? I tried using the ...
1
vote
2answers
45 views

Special Relativity Question: Doppler shift

Imagine an observer watching a moving rocket carrying on it both, a light source and a clock. If on the rocket the clock is synchronized with the frequency of the light being emitted then will not a ...
0
votes
1answer
66 views

Can someone explain effects of time dilation on expansion of universe [duplicate]

I'm not a physics guy, but this is something I have always wondered about. If a clock flown by an object of high mass runs slower, what is the effect of this in regards to the density of the universe. ...