Dilation Definition and 1000 Threads

In physics and relativity, time dilation is the difference in the elapsed time as measured by two clocks. It is either due to a relative velocity between them (special relativistic "kinetic" time dilation) or to a difference in gravitational potential between their locations (general relativistic gravitational time dilation). When unspecified, "time dilation" usually refers to the effect due to velocity.
After compensating for varying signal delays due to the changing distance between an observer and a moving clock (i.e. Doppler effect), the observer will measure the moving clock as ticking slower than a clock that is at rest in the observer's own reference frame. In addition, a clock that is close to a massive body (and which therefore is at lower gravitational potential) will record less elapsed time than a clock situated further from the said massive body (and which is at a higher gravitational potential).
These predictions of the theory of relativity have been repeatedly confirmed by experiment, and they are of practical concern, for instance in the operation of satellite navigation systems such as GPS and Galileo. Time dilation has also been the subject of science fiction works.

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  1. U

    Speed of the light and dilation of time

    If I am 35 years old and I am in a train sitting in a special tube that is built around the entire circumference of the planet. Putting aside all of the questions of practibility and g forces and the like, if the train I am in accelerates to just a hair under the speed of light and I travel on...
  2. M

    What exactly is Time Dilation?

    So I know it has to do with reference frames and such, and I know that it is all about time relative to different observers, what I don't understand is how exactly is it that when you're moving at a speed close to 'c', you actually physically experience a different time interval than someone who...
  3. G

    How does the time dilation is being measured using atomic/quartz clocks?

    I understand time dilation exists according to relativity theory. But what I'm not able to understand is this statement, "clock is ticking faster/slower on a moving object compared to observer". How is that possible to measure it? or how does the clock (atomic/quartz) it experience the time...
  4. K

    Confused about seeming recursivity of time dilation between two moving bodies

    I only just started learning about special relativity in my physics class, and I have been running into a problem that none of my teachers have satisfactorily explained. Objects X and Y are moving relative to one another at some significant fraction of the speed of light, where ɣ is the...
  5. bayan

    Time Dilation at very slow speeds.

    Homework Statement Hi, I have a question which asks me to find the time difference (difference between a stationary frame and one that is moving at 30m/s for 1 hour) it has asked me to use binomial approximation and I am kind of lost as to what I need to do to solve the equation. Homework...
  6. S

    Speed of the light and time dilation

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  7. johann1301

    Time Distortion and Time Dilation

    Is there a difference between Time Distortion and Time Dilation? If so, what's the difference?
  8. R

    Spacetime dilation in special relativity

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  9. K

    Time dilation - Lorentz transformation using light clock

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  10. grav-universe

    Gravitational time dilation

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  11. I

    Time Dilation Data Sets: Get Graphs & Experiments Results

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  12. M

    Calculating Muon Half-Life: Length Contraction vs Time Dilation

    This link is confusing me. http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html In this link, with non-relativistic method, half life is calculated as 21.8. But with relativistic method half life is calculated as 4.36. We calculate half life considering time dilation for muon...
  13. C

    Extremely Basic Question Regarding Time Dilation

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  14. T

    Time dilation analogy. Please tell me if this is accurate.

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  15. P

    General Relativity: Gravitational time dilation of photons and Fabric of Space

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  16. S

    Applying time dilation and length contraction to measure parralel c

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  17. I

    Confirming Time Dilation Without Subatomic Particles: Steven's Question

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  18. Rapier

    Special Relativity and Time Dilation: A Physics Problem in Frames of Reference

    Homework Statement A physics instructor is 22 years older than her student. She decides that instead she would like to be 22 years younger than her student and decides to use special relativity to accomplish this. She jumps in her super rocket travels away from Earth for a period of 1 years...
  19. I

    Time dilation from length contraction

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  20. D

    What are your best arguments for time dilation, so duration is different ?

    I fully understand time dilation if I already could believe it, but I am not convinced yet. What is the most convincing argument for you, that you are sure time dilation exist and so duration is different in locations (when duration is always the same, I believe in time dilation too, that's...
  21. J

    Physics Special Relativity Time Dilation Question?

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  22. S

    Max/Min Time Dilation: What is the Scale?

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  23. D

    Explaining time dilation from length contraction easier

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  24. D

    Rest frame through a force field possible (time dilation) ?

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  25. Z

    Time Dilation Scenario: Einstein's Skaters on a Moving Conveyor Belt

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  26. R

    Time dilation explaination with mechanical clock instead of light clock

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  27. G

    Is Time Reversed in Special Relativity When Moving Opposite to Light?

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  28. D

    Exploring Time Dilation: Understanding the Concept of Relativity in SR

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  29. J

    Special Relativity: Time Dilation

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  30. M

    Time dilation in acceleration or velocity

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  31. S

    Relativity: Time Dilation and Length Contraction

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  32. S

    Introductory Relativity, Time Dilation

    Homework Statement Heide boards a spaceship and travels away from Earth at a constant velocity of 0.45c toward Betelgeuse (a red giant star in the constellation Orion). One year later on Earth clocks, Heide’s twin, Hans, boards a second spaceship and follows her at a constant velocity of 0.95c...
  33. A

    Unraveling the Time Dilation Argument: Does Speed Affect the Passage of Time?

    Me and a few friend are currently having a large argument whether time is actually changing when a shuttle is moving near the speed of light. so the scenario is a shuttle moves near the speed of light for 100 years. with a clock set to 0:00:00 and a person on Earth also has a clock at 0:00:00...
  34. C

    Time dilation in minkowski diagrams

    Hey! I'm trying to understand time dilation in terms of minkowski diagrams. Below I've added a diagram showing the two coordinate systems where the primed one moves relative to the unprimed one with a speed v. http://mindseye.no/wp-content/uploads/2012/01/time1.png My reasoning in this...
  35. K

    Time Dilation and Space Travel: Is Wikipedia example wrong?

    Quoting from Wikipedia: "Time dilation would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. That is, the ship's clock (and according to relativity...
  36. C

    Time dilation vs effects of high speed motion

    I am extremely confused with why time dilation is different from what I've read about traveling at speeds near that of light. I think that I am mixing up two concepts. What I understand is that due to time dilation, both observers would view the other's clock as running slow as long as both...
  37. S

    Does time dilation affect the relative motion that causes it?

    Does the relative motion of a thing slow down the relative motion of a thing? Hope that makes sense or you can work out what I mean.
  38. S

    Does radioactivity suffer time dilation?

    I want to know that if one sends a radioactive material in a spaceship at high speed and bring it back, do we find that the radioactive material has decayed slower than it would on Earth or the same rate? As radioactivity doesn't depend on the Coulombic interaction (photons), rather other...
  39. K

    Time dilation and Length contraction in Saddle Geometries

    The way I've been reading it, elliptic geometries are due to a positive Gaussian curvature, while hyperbolic geometries are due to a negative Gaussian curvature. Do local saddle curvatures mean local time dilation and length contraction, or do they mean local time acceleration and length...
  40. E

    Time dilation derivations - help me out just looking for references

    I'm looking for another derivation of time dilation which does not involve moving clocks or mirrors... I feel like those aren't very clear - is there any other way time dilation has been derived? thanks
  41. H

    Atomic Clock Time Dilation Experiment

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

    Twin paradox and time dilation

    I like astrophysics,so i read books relating to it.I am also determined to make my career in the same.At present i am reading a book ,which includes brief about Einstein's 'Relativity and special relativity' theory.It also explains to some extent the 'Twin paradox' and 'Time dilation'...
  43. S

    Is My Time Dilation Equation Correct?

    hi friends i am really confused with time dilation ... Time is quantity which is defined by us, and it will be always constant then how einstein said the time will dilate when we travel at the speed of light.. thank u...
  44. Nakshatra

    Does Time Dilation Affect Life and Death in Different Frames of Reference?

    It is a thought experiment and based on time dilation. It goes like.. consider a cab moving with a speed close to light.Also the cab has been divide into two equal halves by a glass wall. there are two individuals in cab one in each part of the cab divided by the glass wall.One is very old...
  45. M

    Time Dilation in a Non-Rotating Laser Sphere: Inside vs Outside

    Let's say I had built a machine that is able to slow down time (Travel to the future) by one eighth. If the object creates a non rotating sphere using lasers and it is able to accomplish this task, would the time dilation be stronger in the machine or out of the machine?
  46. J

    Does a clock in free-fall slow due to gravitational time dilation?

    I imagine I have two clocks that are synchronised and are sitting a long way from a large massive body. I hold on to clock A and let clock B fall towards the mass. Let's assume that the falling clock B gets close to the massive body but somehow misses it, swings around and travels back to me...
  47. G

    Time Dilation and Length Contraction the same thing?

    Are these really just two ways of explaining the same thing?
  48. D

    Why are the effects of Time Dilation permanent but Length Contraction is Not?

    This question is in regard to special relativity. From my rudimentary understanding, concerning the twin paradox, if one twin leaves traveling near the speed of light and returns, he will find himself younger than his twin who stayed behind. Hence, the effect of time dilation is permanent...
  49. PrincePhoenix

    Confused about time dilation. (Just got introduced to relativity))

    I just got my first official introduction to relativity in my textbook (I'm equivalent to a high school senior student). It is part of a chapter on modern physics.It first mentions the two basic postulates and then briefly introduces what length contraction, time dilation, increase in mass...
  50. Z

    How Fast is a Clock Moving if It Runs Four Times Slower?

    A moving clock is observed to run four times more slowly than an identical stationary clock. What is its speed relative to the frame of the stationary clock? I'm wondering which equation should I be using for this? Thanks
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