Time dilation Definition and 999 Threads

As I understand it, time dilation can occur under gravity or acceleration, which can be referred to as Gravity Time Dilation and can also appear to be happening when two things are in different frames of reference, which can be referred to as Velocity Time Dilation. With Gravity Time Dilation...

I am not a physicist—not even close—just a guy who, for some crazy reason, decided to try to understand some of the basics of relativity. I’d like to understand them well enough to be able to explain them (correctly) to another lay person. I’m trying to see how much I could explain without...

Hi all! I was messing around with the equation for time dilation. What I wanted to do was see how the time of a moving observer ##t'## changed with respect to the time of a stationary observer ##t##. So I differentiated the equation for time dilation ##t'## with respect to ##t##: $$\frac {dt'}...

According to Einstien's theory of evolution, the closer to the speed of light that an object travels, the slower it appears to move to an outside observer. (see https://www.thenakedscientists.com/forum/index.php?topic=40951.0) To take this to the next step once an object crosses the event...

What I know gravitational time dilation (based on GRT) is dependent on gravity potential and not on gravitational acceleration. That would mean, that for example in center of Earth is the gravitational acceleration zero, but the gravitational potential is bigger than on the surface of Earth...

Hi 1-)If an object's total velocity through space-time(four-velocity)is c, for example even we stand still we move with velocity c (through time) and if mass slows down time, can we say mass also increase our velocity in space? 2-) Is Four-velocity magnitude constant in General Relativity...

Hi I have 2 questions. There are 2 planets and one clock on each of them. One of them has a bigger gravitational field strength. And two clock have same distance from the core. 1-) Does time dilation occur between two? Which clock ticks slower? 2-) If time dilation occurs, which formula...

Special relativity says that all clocks will show same time dilation, irrespective of clock mechanism. But Time period of a clock is a formula that must continue to hold even if time dilates. Let us look at a tuning fork clock. Here time period depends on the dimensions of the vibrating...

I understand time dilation due to speed, but am confused on why time dilates depending on the distance from a mass. Help?

Hello everyone, I'll go straight to the question. The gravitational time dilation is equal to tearth = tspace*sqrt(1 - rs/r), with rs = 2GM/c2. However, the formula for speed of light in gravitational field is equal to v = c(1 - rs/r). My intuition tells me that these two formulas must be the...

Homework Statement A rectangular structure carries clocks at its four corners. The clocks are synchronized in the structure’s rest frame, in which it has length L =4ft and width W = 3ft. In our laboratory frame the rectangle is moving in the positive x direction at speed v = 0.8c. As the clock...

Homework Statement Two atomic clocks are synchronized. One is placed on a satellite, which orbits around the Earth at a high speed for a whole year. The other is placed in a lab and remains at rest, with respect to the earth. You may assume that both clocks can measure time accurately to many...

Homework Statement Imagine that you are flying on an airliner on a long flight to Europe, at a constant speed of 300 m/s. a) You throw a ball towards the back of the plane at 20 m/s. You then shine a beam of light towards the back of the plane. How will these two things—the ball and the...

The Special Theory of Relativity is based on two principles. The first one is, that if you have two objects, then it is not possible to tell which object is moving, and which object is standing still. So someone moving in a spaceship relative to observer, can't say who is actually moving and who...

Here is one for every one to pull apart, it goes beyond every thing I have learnt. arXiv:1804.10274 [pdf, other] Lack of time dilation in type Ia supernovae and Gamma-Ray Bursts David F. Crawford Comments: 4 pages, 2 figures and 1 table Subjects: High Energy Astrophysical Phenomena...

Can someone kindly review my solution to see if I did it correctly. This is an assignment question. Homework Statement If Darth Vader was 50 years old when he left his galaxy in 2007, how old would he be if he returned in 2025 if he had traveled at a rate of 2.8 × 108 m/s? Homework Equations...

If/when we go to Mars how will we deal with time dilation due to the gravitational differences between the two planets?

Hi, We are not learning this in class, but I am giving a presentation on special relativity and as part of my presentation I would like to show that time is not absolute and that if a ship moves away from the Earth for a time t at a speed v then if like 8 years pass on board the ship a greater...

Some time ago there was a similar thread https://www.physicsforums.com/threads/clock-hypothesis-gravity-time-dilation-and-equivalence-principle.929838/ but what I want to discuss is similar but not the same and I would like to specify my question in such way, that it hopefully won't go sideways...

Homework Statement Imagine that you are flying on an airliner on a long flight to Europe, at a constant speed of 300 m/s. a) You throw a ball towards the back of the plane at 20 m/s. You then shine a beam of light towards the back of the plane. How will these two things-the ball and the...

Homework Statement Two atomic clocks are synchronized. One is placed on a satellite, which orbits around the Earth at a high speed for a whole year. The other is placed in a lab and remains at rest, with respect to the earth. You may assume that both clocks can measure time accurately to many...

1. If A is static and B is moving away from A at velocity v, from Einsteinian point of view, is A also moving away from B at the same velocity? If yes, is the similarity of movements and velocities of both A and B valid in every context? If B is experiencing a time dilation from the view point...

How can I derive mathematically law of composition of velocities from time dilation and length contraction But please use only algebra .Don't use four vectors and space time diagrams.

I hope this is the right forum for this question. Imagine alien tech allows them to travel 1 million light years to Earth instantaneously. No thrust, vector, propulsion was involved. They didn't have to approach the speed of light, with its attendant increase in mass. Having arrived at earth, in...

Homework Statement A man is flying with a speed of 0.7c and at a height 1 km. During his flight, he measures the distance between Toronto and Montreal to be 450 km. What is the real distance between them. I don't think the answers are based on real life, they are just examples of places...

10 seconds somewhere can be one on Earth due to time dilation, right? So In the case of distance wouldn't light have traveled more than 186,282 MPS since it had 10 seconds to travel relative to the 1 second on earth. So if light traveled at 186,282MPS for 10 seconds it would have traveled...

Relative to a remote point, when using the standard GR method, how does the rate of time passage (1 / gravitational time dilation) typically vary with radius within a contracting 5 solar mass supernova remnant, when its’ outer radius crosses a value of about 1.6 times the Schwarzschild radius?

In special relativity, an object moving at higher speed experiences time dilation, length contraction, and mass increase, compared to an object moving at slower speed. In general relativity, for an object in stronger gravitational field (i.e., with higher acceleration due to gravity), time runs...

Hello. I have a question. If I am moving with velocity v for an observer O. If I experience and kind if time dilation and my time slows down with respect to observer O's time. But if my time slows down. For O I will be moving slowly in time. If time dilation is large enough. I will almost freeze...

I understand time dilation in both special and general relativity in terms of motion, ie. an object in a gravitational field will move slower than an object outside the field, as the spacetime causes the object in the field to take a longer path to the same destination. Same goes for two objects...

My question is very simple (and I assume it has been discussed before but I cant't find the topic): An atom in the Sun emits a photon detected by an observer on Earth. Disregarding uncertainties and experimental problems relating to the movement of the atom (or assuming we could correct for...

Hi All, An observer, F, stands on Earth. A spaceship, F', is also on Earth. Their clocks are set at 0. The spaceship then leaves Earth at .5c. After 10 seconds, F sends a light signal to F'. As soon as F' receives the signal, F' sends a light signal back. When does F receive this signal from...

Homework Statement A graduate student discovers that an elementary particle produced in his experiment travels 0.250 mm through the lab at a speed of 0.950c before it decays (becomes another particle). What is the lifetime of the particle measured in its rest frame (proper lifetime). A) 8.77 x...

Hello I am new here and I am just Junior college student. So please use simpler terms. I need to know that does relativity work for mediums like air and water. I mean the equations of time dilation and length contraction, do they work for other mediums. If so shall I take C as the speed of light...

At the event horizon for a black hole is R=2GM/C^2 This means that, as a star collapses, it gets more dense until this limit is reached. Assuming a consistent density (just an approximation as I know this will not really be the case), the Mass will reduce proportionally to the cube of R, but...

Hi Couldnt figure this out U have 2 identical clocks where a pulse of light goes from a light source (a), reflects off a mirror (b) and goes to the end (c) A person is stationary wrt one clock and another clock is in a spaceship moving, relative to the observer, in the direction v at velocity...

[Note from mentor: this thread was originally posted in the Quantum Physics forum.] I am looking for a way to mathematically express the orbit of an electron around the nucleus of a hydrogen atom, while the atom is stationary as well as in motion. Note the orbit of the electron is 3...

Hi, I've always had a doubt concerning time dilation, and today the curiosity got the best and I decided to ask people that know their stuff, you people. Maybe the question has been asked before, but I did a quick search and couldn't find it, sorry if that's the case. Well, here it goes. As I...

In the image below, we will be accelerating the entire apparatus. It won't ever reach a frame of inertia. Would someone in a different frame of reference be able to detect this acceleration from the output of the photo-detector? As time slows and the distance the laser travels contracts; would...

Is time dilation defined by Special Relativity, General Relativity or both? The topic of time dilation seems to come up often. So I thought I would pose a question, and give my summary and conclusions. I've recently been struggling to understand time dilation. While researching this topic l...

I continue to see references to time dilation that I don’t understand. Maybe the bluntest one is in a textbook by Resnick. Introduction to Special Relativity, p. 93: “Indeed we find that the phenomena are reciprocal. That is, just as A’s clock seems to B to run slow, so does B’s clock seem to...

Hello. I want to clear a doubt on Special Relativity, time dilation and clocks. If we get an accurate clock and make it orbit the, for example, Earth very, very fast, will the actual mechanical clock lag behind from the accurate clocks on Earth? The thing in this question is about the actual...

Homework Statement Anna and Bob are both born just as Anna's spaceship passes Earth at 0.9c. According to Bob on Earth, Planet Z is a fixed 30 ly away. As Anna passes Planet Z on her continuing outward journey, what will be (a) Bob's age according to Bob, (b) Bob's age according to Anna, (c)...

I try to find the formula of dilation of time between a reference frame (R') moving at a speed v and a fixed observer in (R). For this, I take the example that we often find as a demo : that of a train in which a light beam is emitted vertically (in the train): this vertical trajectory in the...

1. The Clock Hypothesis states that the rate of a clock does not depend on its acceleration but only on its instantaneous velocity. This has been experimentally verified at very high accelerations. 2. A clock in a gravitational field experiences time dilation and runs slower that one not in a...

That is to say, how does time behave in a region of space where multiple gravitational fields cancel out their accelerating effects? I understand that time "slows down" in a gravitational field, but does this depend on the actual presence of the field, or instead the actual net acceleration...

Feel free to correct anything I state here. I'm trying my best to understand some rather complex (for me) ideas about time dilation. So if I understand correctly, increasing velocity compresses time, causing you to exist more slowly relative to anyone not moving at that velocity. Similarly, the...

I have a question about the gravitational time dilation explained in Appendix B of the book "Cosmology" written by S. Weinberg. Why can the author say "In the negative gravitational potential at the surface of a star clocks therefore tick more slowly than in interstellar space, or in the much...

Does anyone know if any mechanical clocks have ever been accurate enough to show time dilation? (That would be a clock with a spring-mass harmonic oscillator.) Is there any reason to suspect they might not show the same thing as the atomic clocks? (Pendulum clocks would not, for example. They...

For example, Brian Greene says in The Elegant Universe regarding special relativity and train moving with constant velocity relative to platform: By the principle of relativity or first postulate, "there is no way for an observer on this train to detect any influence of the train's motion. But...