Questions tagged [time-dilation]

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Time dilation derived from first principles vs. “width contraction”

Wikipedia describes the usual derivation of time dilation with a moving light clock: In this and similar derivations nothing is ever said about a possible "width contraction" and why it does not ...
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Calculating Time in different reference frames

Consider the following problem. A stick passes with speed v though a breadthless person whose(the stick) proper length is L. How does: Stick See the time elapsed on my clock? I see time elapsed on my ...
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Time dilation inside a black hole

A clock is sent towards a black hole. My understanding is that because of time dilation, the clock will appear to tick more and more slowly to an observer on Earth, to the point where the time ...
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If time in proximity of a big mass is dilated, the energy that “escapes” the system is dilated in time as well?

Let's suppose to have a black hole and an accretion disk. The disk will produce a certain amount of visible light, but since for a far observer time is going faster does it mean that the observer will ...
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Spacetime diagrams and their interpretation

Recently started an introductory course of relativity, and started learning about space time diagrams. I couldn’t figure out what are the uses of a spacetime diagram as an alternative to Lorentz ...
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How does time dilation affect the ability of photons to escape a black hole?

The curved space explanation of why light can't escape from a black hole is great but... I'm also wondering how time-dilation affects a subatomic particle trying to escape at the speed of light. Can ...
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When a black hole explodes due to hawking radiation, how does the curvature of space previously within the event horizon behave?

I'm thinking about the time dilation in terms of distance from the singularity, to the event horizon and outside it. After a black hole has lost its necessary mass to maintain its singularity through ...
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Bob sees Alice never reaching the event horizon. What does Alice see when looking at Bob?

Alice is in a rocket hovering outside a BH event horizon when her rocket runs out of fuel, and thus begins a free-fall decent. Bob is also in an inertial frame but at a very large distance. It is ...
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SR time dilation discussion meaningless when there is gravity?

Let us say you have three clocks fixed to the spinning earth at the equator. If you set one of this clocks on a plane going eastwards around the globe it will have measured a lesser amount of time ...
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What creates the physical difference in ageing when travelling close to the speed of light? [duplicate]

I probably have a fundamental misunderstanding, so correct me if I'm wrong. When travelling close to the speed of light, movers experience time dilation, which is what results in the phenomenon of ...
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153 views

Communication near a black hole

One ship is in a stable orbit outside of the event horizon of a very large black hole so that there is significant time dilation. Another ship is in its own orbit around the same black hole, but at a ...
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1answer
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Is it speed or acceleration that leads to time dilation? [duplicate]

Is it acceleration or speed that leads to time dilation or both? For example, when a spaceship accelerated to (almost) the speed of light, then reversed course to come back towards earth, does this ...
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Time dilation in a gravitational field

A friend and I were talking about relativity and we had different opinions about this situation: If I choose a frame of reference on the surface of a planet, would time "run" differently between the ...
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Query about the Michelson interferometer

Say I am cycling past a Michelson interferometer set up. Someone at rest with the experiment will see both beams travelling a distance $L_0$ and hence conclude that $T_{AB}=T_{AC}=\frac{2L_0}{c}$. ...
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Subtle problem in length contraction

Suppose a particle moves with respect to objects. Does length contraction refer to the contraction of the particle, or to the separation between objects? It seems to me it can't be both. The former ...
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Time dilation for a moving electronic clock

Is this a correct application for the time dilation theorem? Suppose an electronic clock has a copper wire of length $d$, which allows the electrons to take $t$ seconds to complete a cycle on the $d$-...
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Question about position dependence of time dilation?

I found this picture from a physics stack exchange question on time dilation: Time dilation all messed up! I am now returning to it a few weeks later and was wondering if I am correctly interpreting ...
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What would be the time dilation standing on a neutron star in comparison to earth?

What would be the combined gravitational and velocity time dilation one would experience if they stood on the surface of a neutron star in comparison to standing on the earth's surface? Specifically, ...
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Higgs field and Time dilation

I am wondering if the Higgs field is related to time dilation. Photons travel at the speed of light, but muons are very close but never at the speed of light. Would Muons be slowed by the interaction ...
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Question about twin paradox

I just started to learned modern physic for a two weeks, and the i got some problem to understand about the resolution of twin paradox I have attached two pages of picture above that makes me ...
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Does time dialation cancellation occur between two observers moving in opposite directions [duplicate]

This is the question that has been on my mind lately: If an object A is moving away from an object B which is presumed stationary by A, then the time observed from the perspective of object B will ...
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Muon decay in muons frame of reference, time muon expects us to record

I have already asked a question regarding this concept but it was flagged as a duplicate. I know this misconception is very common for special relativity but I haven't found a question that talks ...
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Can time dilation show who's moving?

Imagine a person going in a spacecraft moving away from the Earth, when he return from his journey he notice the time has passed slowly than for the habitants on the Earth. Noting this, we can ...
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1answer
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How much does time-dilation effect our observance of the most massive objects in our solar system?

Disclaimer: I'm kind of a newb, so I apologize if this question is not well formed. Please comment if anything is unclear, and I will do my best to make corrections. Reading this post about time ...
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Special relativity and time dilation

Im studying Relativity and there is something that my mind really cant proccess right now. That would be the Deformation of time on heavily gravitational bodies. For an example lets take the movie ...
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754 views

Gravitational time dilation compensated by acceleration

I would like to compare the time indicated by two clocks: clock A is located at the top of a mountain, the clock B is in an helicopter flying stationnary at the same altitude than the clock A. Clock ...
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1answer
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Respect to What Time is Calculated in Space

This may be the silly and stupid question but I have read that time appears to move slower near massive objects because the object's gravitational force bends space-time and the phenomenon is called ...
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Why doesn't time dilation prevent black holes from growing?

From the point of view of an external observer, matter falling into the black hole is supposed to never cross the event horizon due to time dilation. At the same time, black holes are supposed to ...
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Trouble understanding time dilation [duplicate]

I am new to relativity, so I am sorry if this question is stupid. I've been having some trouble understanding time dilation. My problem comprises of a spaceship moving at a very high speed relative to ...
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Gravitational Time Dilation - What is wrong with this graph? [duplicate]

I am trying to plot the gravitational time dilation as a function of orbital height. But I seem to do something wrong: $$ dt=\frac{\mu s}{d}\left(\sqrt{1 - \frac{2GM}{(r_E+x)c^2}}-\sqrt{1 - \frac{2GM}{...
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1answer
96 views

Deriving Doppler effect in observer's frame

I am attempting to find the Doppler factor from the frame of the observer. In the frame of the observer, the source is moving at velocity $v$ towards the observer. Since the source emits at time ...
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Gravitational time dilation derivation

One way of deriving gravitational time dilation is to imagine an observer in free fall in some gravitational field passing by two observers stationary in that field. Because inertial observer passes ...
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Time Dilation and Particle Decay

I am teaching myself astronomy and I'm working on a basic problem regarding time dilation around black holes. The question is basically this: if a neutron were ejected from a nucleus at a distance of ...
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Method to observe clocks on spaceships moving near $c$?

I have read the explanation for clocks slowing down on a spaceship moving relative to a stationary observer -- something like a beam of light between two mirrors taking longer for the observer to ...
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What is the relationship between time dilation and gravitational time dilation? [duplicate]

This may be a stupid question as I have no background in physics but I'm curious: We know time stops when approaching the speed of light and also as object approaches the event horizon of a black ...
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How can we justify time dilation if we look through an spyglass at Einstein's light clock?

Assume that a space shuttle travels in a circular path having a radius $r_s$ at a tangential speed $v_s$ - a considerable fraction of the speed of light. There is a light clock inside the shuttle ...
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Is there a connection between the energy distribution and time dilation?

Can anyone please help me understand what is descibed bellow? Scenario 1. We have a pair of atomic clocks. Let's call them clock A and clock B. We switch both of them on at the same time. Clock A ...
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Apparent FTL speeds seen by observer

MY guestion is if I was in a ship orbiting a black hole (not very close to the event horizon) I am orbiting pretty far and I am experiencing that my time is slowing down realitive to people on earth. ...
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How to calculate mass from time dilation and radius?

I'm new to this site and I'm been searching the internet all over for this solution. I'm looking for an equation, that if given the time dilation at the surface of an object and its radius, it will ...
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What do you think of this conceptualization of the universe and time dilation? [closed]

So the universe is ever-expanding. It's been expanding in all directions since the Big Bang, like how a sponge expands when you give it water. The universe is made of a fabric known as space-time. The ...
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Should we need to consider time dilation effect when travel in a very fast rocket? [duplicate]

How long does it take for a rocket to reach a planet 10 light years away if the rocket's speed is just near the light speed? If the speed is 1 c, the folks will answer it will take 10 year to travel ...
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Photon emittance of objects under the effect of time dilation

Light that is emitted from objects under the effect of time dilation (from out point of view) is redshifted that much is clear. However I am interested if another effect occurs that I never seem to be ...
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Time dilation, and curvature of space caused by two black holes of unequal masses

If you were to try to find the time dilation in a region of space near a black hole you would use the equation $$t_r=\sqrt{1-\frac{2GM}{rc^2}}$$ Would the time dilation from two black holes be this? ...
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If things travel at different time rates due to relativity wouldn't one of them disappear from my perspective? [closed]

If I travel to a 3d location where Einstein was known to have existed at some other time, I do not expect to see him, because his 4d location is different! Why then can I send a clock around a black ...
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Interpreting Time in Bells Spaceship Paradox

I’ve seen a lot of arguing about Bells Spaceship Paradox, so it appears to confuse even some physicists. In Bells Spaceship Paradox, two ships begin simultaneously accelerating at a constant rate ...
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Problem on derivation of time dilation

In my lecture notes, there are two frames S and S'. The prime frame moves with uniform velocity with respect to the unprimed frame. In this frame, she derives the time dilation equation in the ...
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How do we determine who is the “observer” when calculating time dilation? [duplicate]

I was reading about time dilation and I thought of a question. I really think that I am just misunderstanding something, so please bare with the question. But, I would appreciate if somebody could ...
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When photons are moving at the speed of light, how come they change in position?

From what i know, photons are moving at the speed of light and that means the time that photons are experiencing is zero, but here is the thing... If the time is zero how can they travel astronomical ...
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Trying to understand velocity addition and time dilation [duplicate]

I'm familiar with Einstein's formulae $V=\frac{u+v}{1+ \frac{uv}{c^2}}$ and $\Delta t'=\frac{\Delta t}{\sqrt{1-\frac{v^2}{c^2}}}$, the former being velocity addition and the latter being time dilation....
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Problem in Special Relativity [closed]

"A space probe is sent to the vicinity of star Capella, which is $D = 42.2 \ light \ years $ from earth. The probe travels with a speed of 0.9930c. An astronaut recruit on board is 19 years old when ...