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7
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2answers
2k views

Why we don't see time dilation in stars orbiting black hole?

We have images of stars orbiting black holes or black holes destroying near stars, but why do we see the stars moving normally? I mean, if time dilation does exist, shouldn't we see that stars slow ...
0
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2answers
49 views

If the measurements of a clock above the earth depend on orientation, then what measurements are correct?

Take a clock in space above the earth (assuming a Schwarzchild spacetime) that works by relaying a light signal a small distance radially; ticking each time the light signal returns. Compare this to ...
-1
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2answers
60 views

Measurement of the speed of light form different perspectives

I've been showing a special interest in Einstein's theory of relativity and how he proved the speed of light to be always the same. At first it was a bit hard for me to understand, but now I THINK I ...
1
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2answers
61 views

Possible paradox with black holes and time dilation [duplicate]

I am by no means an expert in the realm of physics. I do from time to time, try to understand the concepts of modern physics and their applications. I came across this video that I am currently ...
1
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1answer
159 views

Effects of relativity on New Horizons spacecraft

How much would an atomic clock on board the new horizons spacecraft drift in comparison to an atomic clock on the surface of the earth near the equator after the spacecraft's 10 year journey to Pluto? ...
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0answers
26 views

Is helping others grasp difficult ideas, concepts or theories not considered giving an answer? [migrated]

I know you could just leave a comment, but not in this case I couldn't. I just found this awesome app while researching on my passion, physics. I stumbled across a question about time dilation, not ...
1
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1answer
69 views

Hafele-Keating revisited with a gravity clock

Most modern clocks use electromagnetic phenomena to measure time. There are perhaps some older clocks that involve gravity to some degree (hour glass, pendulum), but I believe they still have a ...
1
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4answers
209 views

Why is the momentum of a particle $\gamma mv$?

I am very new to relativity, and as I was going through Resnick & Halliday, I saw that momentum was no longer $mv$, rather $\gamma mv$. This was the proof: $$p = mv = m \frac{\delta x}{\delta ...
0
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1answer
72 views

The age of black holes

I have a very small understanding of space-time however I have been watching some interviews and reading articles featuring theoretical physicist Kip Thorne and I have a few questions that I hope can ...
4
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3answers
439 views

How much fuel is required for star travel considering relativistic time dilation?

John Rennie's Q&A How long would it take me to travel to a distant star? discusses about interstellar travel taking into consideration. There was a case that discussed about constant ...
1
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0answers
74 views

Does negative mass reverse the arrow of time?

General relativity predicts that normal mass (positive mass) results in the curvature of spacetime which in return leads to gravitation. Since space and time are bonded together, any change on the ...
4
votes
1answer
140 views

Are we traveling through time at the speed of light? [duplicate]

In the image below the y axis represents time and x represent velocity. Point D represents velocity c, point E represents 1 second per stationary observers second. What this chart is showing is as you ...
0
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1answer
50 views

time dilation :-

In the time dilation equation $t'=t/\sqrt{1-(v/c)^2}$ where $ t'$ is the time measured by an observer in motion for the same event, where $t$ is time measured by the observer at rest. Imagine a ...
2
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2answers
72 views

Watching a LIVE stream in spaceship traveling away from earth close to speed of light

My name is Dennis. This might sound just straight up ignorant of basic concepts of physics. I was having a conversation with my friend in regards to streaming a LIVE event on earth to a spaceship ...
0
votes
1answer
115 views

Understanding gravitational time dilation / Schwarzschild metric

I've had a look at the answers to these sorts of questions already, but feel like I'm still missing something. Starting with this question, and this one and even this one here. I'm looking at this ...
1
vote
1answer
60 views

Time flow difference for satellites [duplicate]

Clocks in satellites have to be adjusted due to the effects of relativity; but does time for satellites (GPS) flow slower, due to the relative motion, or faster, due to the weaker amount of ...
2
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3answers
103 views

Milky Way galaxy central black hole and time contraction of life story

We know that life is almost 4 billion years old on Earth. We also know that time contracts as we approach the event horizon of the massive black hole at the center of the Milky Way galaxy. Now the ...
-1
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1answer
52 views

Time dilation and biological changes

I have watched the movie Interstellar and like most of the people who watch it, I was intrigued by the effects of time travel on the astronauts. After reading some articles and watching some videos, I ...
0
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1answer
38 views

Symmetric Time Dilation in Uniform Relative Motion

I feel (and hope) this is an easily answerable question among physicists versed in GR. I promise that I searched for other answers on the forum. Here goes: Observer 1 starts at X distance from ...
0
votes
2answers
109 views

Could time dilation bend the path of a photon? Does time dilation have a refractive index?

The main question I am getting at is, does time dilation have a refractive index? What I mean is, if I were to shoot a laser past a black hole, would the laser's path "bend" strictly from time ...
1
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3answers
99 views

Time dilation, reference frame

If we have two objects (clocks) in (empty) space and they separate (the distance between them increases) at relativistic speeds then get back together (just for easier comparison of their times), what ...
1
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2answers
100 views

Is time dilation based on the formula for period of a pendulum?

The theory Albert Einstein put forward about special relativity mentions a possibility for time dilation, in which he states gravity has a considerable effect on time. And in high school physics we ...
2
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1answer
57 views

Is there a time dilation between my left and right arms?

Is there a time dilation between my left and right arms when walking? due to special relativity I guess Thanks
4
votes
2answers
98 views

where is the logical hole in this reasoning? (special relativity)

I cannot see the problem in the following reasoning, so I'd be glad if you could help me out. The problem is defining a notion of "length" that is consistent with the constancy of the speed of light ...
2
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2answers
118 views

Does time dilation imply that events do not take place?

I take two mirrors parallel and facing each other. A light pulse is being infinitely reflected between the two mirrors $M_1,M_2$. $E_1,E_2$ are the events when the pulse is reflected by $M_1,M_2$, ...
0
votes
2answers
40 views

Does Energy have a similar effect on time as Mass would when considering the gravitational field both exert?

I was thinking about light and the different frequencies. The higher the frequency the more energetic the photon. The higher frequency photon being more energetic seems counterintuitive when ...
0
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0answers
23 views

Gravitational Time Dilation Near Center of Gravity [duplicate]

Stretch your imagination a bit and imagine an almost empty universe with nothing in it but a very, very large asteroid (or an asteroid in our universe but in an almost empty patch so it's not affected ...
8
votes
1answer
72 views

What's the smallest height difference over which gravitational time dilation has been experimentally observed?

In a famous experiment, reported in Optical Clocks and Relativity. CW Chou, DB Hume, T Rosenband and DJ Wineland. Science 329 no. 5999 pp. 1630-1633 (2010); NIST eprint. and nicely described in ...
4
votes
2answers
211 views

How do we age if we tunneled to Earth's core?

Scenario Suppose there exists an advanced technology that can hypothetically transport living humans to study the center of the Earth, as they goes deeper underground most of the Earth's mass would ...
0
votes
1answer
56 views

Time relativity / paradox [duplicate]

After watching the movie Interstellar, the theory of time relativity / paradox really mind-boggles me. If it is true that gravity controls everything even to the extent of time, then it might as well ...
3
votes
1answer
121 views

What are the photon/electron consequences of matter in a gravitational time dilation?

So I saw the movie Interstellar, and it got me thinking. I won't even mention all the plot holes, but I wanted to ask about a planet orbiting a black hole. I always thought you had to travel near the ...
1
vote
1answer
91 views

Since the Earth is moving through space, do we experience time dilation?

What I mean is, the Earth orbits around the sun at around 30km/s, while I understand that this isn't a very high velocity does time dilation still occur to say a person who is completely stationary in ...
2
votes
2answers
149 views

Can light travel faster?

I'm on Earth. Joel is on a planet orbiting near a black-hole's horizon. Every year on Joel's planet is equivalent to 10000 years on Earth due to the gravity of the BH. The two planets are 10000 ...
1
vote
1answer
26 views

Is gravitational time dilation the same for an object at $x$ radii from a black hole no matter what size the black hole is?

Assuming you have two non-rotating black holes. Black hole 1 is 1 meter in radius while black hole 2 is 10 meters in radius. If you are standing 10 meters from black hole 1, would you experience the ...
0
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1answer
37 views

How does the photon differentiate between events?

As far as I know for a photon that's moving at the speed of light (obviously) time comes to a halt and space contracts to a point, making all travels instant from its perspective. Now this is the part ...
1
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2answers
232 views

Why are the proper time and the proper length not defined in the same frame of reference?

I've just read this interesting Wikipedia article about time dilation and length contraction in special relativity. . Derivation of time dilation Applying the above postulates, consider the ...
0
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0answers
45 views

How can matter reach the singularity of a black hole if time stops at the event horizon? [duplicate]

Black holes are said to be composed of two parts: A singularity at the center, where all the mass of the black hole is condensed in a point of zero volume. A black and empty ball delimited by the ...
0
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3answers
88 views

How does an electromagnetic field oscillate if time does not pass for the speed of light?

As far as I'm aware, traveling at $c$ will prevent time passing due to time dilation. Electromagnetic waves rely upon oscillations to propagate. Since oscillations rely upon the passing of time, how ...
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2answers
68 views

Time Dilation: One observer at rest, two observers in motion

I am currently taking a course in Modern Physics mainly focused on Special Relativity and came up with the following problem: Let $O_1$ be an observer at rest. A second observer $O_2$ is moving to ...
15
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6answers
3k views

Is it possible to watch the same distant star's supernova event twice?

Usually relativistic time dilation effects require something traveling near the speed of light. But the high speed requirement can be replaced with a high distance requirement instead. Traveling away ...
0
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1answer
31 views

What is speed relative to in time dilation? [duplicate]

This has always baffled me. There is no absolute speed as I understand(or is there)? Speed is a relationship between two objects. So how can you calculate how much time slows down for an object ...
9
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1answer
240 views

Would time dilation cause a planet to rotate?

For the sake of the argument lets use a black hole so the time dilation effects are greater and the planet in question is orbiting close enough to have significant TD effects but far enough to not ...
0
votes
1answer
47 views

Time and speed - Theory of relativity - 'felt time'

Assuming time is relative according to the objects current speed, means that a clock within a space shuttle which has 30% of light speed is 'ticking' slower than a clock staying on planet earth just ...
0
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0answers
39 views

The limited Computing Capabilities of Space, Increased quantized info leads to time-dilation?

Are there any approaches to Special and General Relativity using space as a computing medium? With space having a maximum computing capability and time dilation as lag? Could this idea describe the ...
0
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1answer
82 views

Time dilation as an effect of energy density

Has any relation been observed or postulated to exist between the energy-density (or the surrounding space) of an object and time dilation? i.e. Higher energy density==>Slower rate of time?
0
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1answer
37 views

Energy variations of cosmic background radiation

Has anyone been able to measure a difference in the energy density of Cosmic Background Radiation in a gravity well compared to zero gravity?
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2answers
84 views

Time dilation due to change in speed

I can't get something strait... Lets use the usual example: A man is flying away from earth on a very fast spaceship. So, His time is now not moving in the same "speed" like earth time but slower. But ...
1
vote
1answer
39 views

At what velocity would a body need to travel at to experience noticeable (couple minutes) time distortion?

When a person experiences higher speeds, the light must travel a greater distance to reach the person whom is moving compared to that whom is staying still. Right? So therefore, light takes slightly ...
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1answer
42 views

Can surrounding masses influence the speed of time (excluding the time dilation due to gravity)?

https://www.youtube.com/watch?v=ev9zrt__lec @6:22-7:22 If you removed the middle and front spaceships, will the time of the last spaceship flow differently? As this is what it appears to suggest.
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2answers
89 views

Special relativity thought experiement

Say you see a spaceship moving relative to you. On this ship you see a timer. When a beam of light is emitted from one end of the ship the timer starts. When the light reaches the other end of the ...