Questions tagged [time-dilation]
This tag is for questions regarding the 'time dilation' which is the lengthening of the time interval between two events for an observer in an inertial frame that is moving with respect to the rest frame of the events (in which the events occur at the same location).
1,439 questions
8 votes
3 answers
1k views
Which wins the race, the neutrino or the photon? [closed]
You have an emitter at A and a reciever at B. Exactly half way between them is a star. The emitter simultaneously emits a burst of photons as well as a burst of moderatly high-energy neutrinos. The ...
- 3,635
-3 votes
1 answer
93 views
Why can't only time dilation alone take place in special relativity, without length contraction? [closed]
In Einstein's special relativity, why can't just time dilation alone take place(without length contraction)? I mean if we slow down the time of the moving object/person, isn't it/or the person already ...
- 111
3 votes
2 answers
292 views
Can a rotating or charged object have time speed up as you approach?
The Reissner–Nordström metric has a gravitational time dilation defined by $$y=\sqrt{\frac{r^2}{Q^2+r(r-2M)}} .$$ Note that there is a charge squared term there, but the term for the mass in linear. ...
- 3,635
-5 votes
2 answers
110 views
Time dilation will not determine whether the speed of light is isotropic or anisotropic [duplicate]
It is well known that one can create an alternate form of special relativity where the speed of light is different in different directions and yet make all the same predictions of orthodox special ...
- 1,361
5 votes
4 answers
484 views
Inertial frames, the speed of light and contraction and dilation of time
From the postulate that the speed of light is constant how it follows that if we have a static inertial frame and next moving inertial frame and we send the beam once in the direction of the movement ...
- 79
12 votes
3 answers
3k views
If gravity bends spacetime, why don’t we detect time dilation gradients inside large objects like Earth?
General relativity says that mass curves spacetime, and that time passes slightly slower in stronger gravitational fields. But the gravitational field changes continuously inside Earth. Does that mean ...
- 895
8 votes
3 answers
1k views
Does a distant observer see the light for a longer duration due to the effect of time dilation?
I am currently learning about the basics of relativity and the concept of time dilation. I was thinking of an event as described below and curious to know what would happen Suppose, one shines a laser ...
- 201
1 vote
6 answers
1k views
The slowing down of time for an observer moving at near light speed
According to the theory of relativity, time slows down for someone traveling near the speed of light. Shouldn't time actually speed up for that person, in order for time to pass by so fast on earth?
- 27
2 votes
1 answer
173 views
Periodically signaling object falling into a black-hole
Say that a distant, stationary (relative to the star) observer signals every 1-second (by the observer's own clock) to an object free-falling into a black-hole. Will the frequency of the signals ...
- 141
4 votes
1 answer
242 views
Is time dilation in gravity truly indistinguishable from acceleration?
The equivalence principle says they’re locally indistinguishable. But is there a measurable, nonlocal experiment (e.g. involving tidal forces or redshift gradients) that distinguishes between ...
- 895
0 votes
1 answer
120 views
Rindler Time Dilation vs Gravitational Time Dilation in Accelerating Refernece Frame
I am trying to reconcile Rindler time dilation with gravitational time dilation between two points in an accelerating frame of reference separated by a distance d (e.g. 1 light-second). As far as I ...
- 71
3 votes
1 answer
502 views
If time slows near a black hole, could information ever be truly lost from the outside perspective?
If time slows down near a black hole, then to someone watching from far away, anything falling in would seem to freeze at the edge. So, does that mean the information never really disappears, or is it ...
- 895
1 vote
2 answers
164 views
Imagined spacecraft acc/decelerating at 1g to/from near $c$: Does the destination star not move faster than $c$?
Motivated by Andy Weir's novel Hail Mary, I was just reading an answer regarding the time needed to travel between stars with a constant acceleration (and deceleration after the mid-way point). Due to ...
- 4,635
1 vote
1 answer
149 views
Time dilation explained conceptually
I am trying to figure out how to extrapolate time dilation just from knowing the constancy of the speed of light and the principle of relativity that no observer should be able to say he is in motion. ...
3 votes
1 answer
210 views
Looking for an expression of gravitational time dilation as a function only of mass density, without any reference to distance
Setup for the question: Under the Cosmological Principle, mass and energy density can be treated as homogenous and isotropic at large scale. This Principle can be applied to any scale in a model. We ...
