What is Time dialation: Definition and 70 Discussions

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. misterously

    I Can someone falsify this analogy contradicting time dilation?

    A spaceship travels at the speed of light from the sun to the earth and back, infinite acceleration and deceleration. Sunlight takes about 8 minutes to reach earth. On the trip to earth, the sun seems to be frozen. On the trip back, sun activity appears to resume and is seen at 2x speed. The...
  2. M

    I From our reference frame, how would a black hole ever form?

    Looking at Kruskal diagrams, it seems to me we should not be able to see evidence of black holes. Assuming our frame is a hyperbola of roughly constant ##r## in such a diagram, as the black hole's constituent mass comes together time slows (from our POV) to the extent that it never crosses the...
  3. R

    I Light Clock Relativity: Why Divide T_moving/T_stationary?

    In special relativity I can get ## \gamma ## , ## \frac {T_B}{T_A}=\gamma ## Why do I not go ##{T_B} - {T_A} = \gamma## ? ##T_B = \frac {2H} {c^2 - v^2}## . ## T_B ## is the moving light clock. ## T_A = \frac {2H} {c^2} ## . ##T_A ## is the stationary light clockI assume LaTeX doesn't work...
  4. S

    I Time Dilation Paradoxes Near C: Exploring the Twin Paradox of Special Relativity

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  5. D

    I Time & Gravity in Rotating Faster Than Light?

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  6. F

    I Can Black Holes Transport Mass Back in Time?

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  7. S

    I Time Dilation: Does Gravitational Field Strength Matter?

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  8. M

    I SR Time Dilation in Rigid Structure Clocks

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  9. Y

    I Interstellar Travel Without Propulsion or Time Dilation

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  10. D

    Simple Special Relativity Problem of Length Contraction

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  11. I

    Special Relativity: Traveling to Regulus

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  12. S

    B Relativity’s Effect on Consciousness

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  13. A

    I Time Dilation: One Year in Jupiter = How Many Years on Earth?

    If we assume I live in Jupiter and there is one year passed in my clock how many years passes in the earth? And how can I use that Equation in the attached?
  14. Ranvir

    B Why is interstellar travel so hopelessly difficult?

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  15. L

    Special Relativity -- two ships moving in one dimension

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  16. V

    A Time dilation for the clock in the orbit

    Suppose that we want to compute the total time dilation for a clock located in an orbiting satellite relative to the clock in our cell phone on the ground. Consider two different approaches below. 1. Use special relativity and compute time contraction due to velocity. Use approximation of...
  17. Looeelooee1

    B Solving Weird Time Dilation Question w/ Spaceships

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  18. A

    B How Does Time Dilation Influence Perceived Velocity?

    Hello I have a question about how time effects velocity:So we have a car on Earth traveling 200m with 5 seconds we get that car moves 40m/s and 40x3600=144000 and 144000:1000=144km/h so car on Earth travels 144km/h now let's consider a that there is observer on spacecraft traveling 0.5c...
  19. KaleLetendre

    I Calculating Radius and Mass of Disc for Velocity 0.75C

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  20. C

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  21. J

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  22. D

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  23. N

    Time Dilation & Effects of Gravity: Exploring the Possibilities

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  24. F

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  25. D

    Time Dilation Confusion: Need Help Understanding

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  26. Prashan Shan

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  27. TheFloppyFIsh

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  28. S

    Calculating moving speaker through two detectors

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  29. arpon

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  30. M

    Geometry of Time Dilation

    I was recently exploring time dilation from Gravity and from velocity and I came up with an interesting derivation that I have not seen before. I was wondering if there is a paper published showing these relationships like this before and where I could find it? First you start with the...
  31. applestrudle

    Special Relativity Time Dilation Santa question

    I am doing a presentation and want to make sure I'm not misunderstanding something very fundamental. My argument goes like this: t0 = ϒt Santa is moving very fast and from his point of view he is in proper time. This means that if it takes him t0 seconds to deliver a present, the amount of...
  32. N

    Time Dilation in General Relativity: Twins Paradox Explained

    I have always been confused about time dilation in General Relativity. In the twins paradox, it is the traveling twin that ages slower. However, could you not just as easily say that it is the non-traveling twin that is moving away from the other? So why is it the traveling twin and not...
  33. rcgldr

    Time dialation effect on observed speed of light

    Assume observer is located on the surface of the Earth with a small amount of time dilation due to gravity. There are two beams of light moving approximately parallel to the surface of the Earth at some moment in time and the reflection of the beam off some objects back to the observer is being...
  34. 1

    Time Dilation on Spinning Atoms?

    would time dilation occur if for example, i was making a hydrogen atom spin with the center of spin the atom? would time dilation occur? because it didn't really traveled distance... or, if so spin a muon, would it decay faster if i was to spin it in an incredible amount of speed? but then if...
  35. E

    Gravity offsetting Velocity's Time Dialation? Trouble Understanding

    Hi All, I am new to these forums. I've been studying relativity in my down time at work and I am having a bit of trouble understanding why gravity doesn't offset velocity in the popular "aging/time travel" theory/scenario. I’ll explain: What I think I understand: The speed of light is...
  36. Z

    Two Events in Special Relativity with on Time Dialation

    Homework Statement A Nova is a sudden, brief brightening of a star. Suppose Earth astronomers see two novas occur simultaneously, one in the constellation Orion and the other in the constellation Lyra. Both nova are the same distance from Earth, 2.5 E 3 c.y (lightyear) and are in exactly...
  37. F

    Time dialation in different parts of a fast moving rocket

    I have no idea if I am picturing this whole scenario wrong, so please hear me out and try to point me in the right direction. Anyways, say we have a fast moving rocket with a person in it. Lightning strikes a side of it. So the light traveling from the bolt to the person/observer is traveling...
  38. G

    Does time dialation cause mass reduction in GR?

    I love Physics! I've been thinking about if... you were in a room with a window, bouncing a ball... and you were looking at another building where you could see a room with a person bouncing a ball, but ... their time was moving at half speed (Caused by gravitational time dilation only ( not...
  39. I

    Time Dialation and Biological systems

    Can anyone prove that Time Dialation affects biological systems?
  40. R

    Light speed; time dialation theory and its age

    Hi All.. I have a basic doubt in time dilation theory. As per time dilation theory, when an object moves with the velocity of light, then relatively its time becomes zero. In that case, light is traveling at 'velocity of light'. So for light, there is no age? Or I misconcepted time dilation...
  41. K

    Hypothetical question about time dialation

    A spaceship has managed to accelerate to 86.6% of lightspeed. Focusing on special relativity would fuel consumption remain the same, better, or worse as opposed to traveling at non-relativistic velocities, what about breathable air? I understand that the rate of fuel consumption would...
  42. MartinJH

    Confusion with time dialation.

    Reading Brian Cox and Jeff Forshaw's book "Why does E=MC2". They mention that satellites speed up with time, but, then reading Wiki it says the crew of the ISS experience the slowing of time. Which one is correct? I'm slightly confused. Both experience a weaker gravitational pull and high...
  43. D

    Time dialation when viewing across the universe

    Hi. Just watched a Nova special with Brian Greene, "The Fabric of the Universe/The Illusion of time", describing significant time dilation when two frames are moving towards or away from each other at low velocities, when the two frames are separated by great distance. This left me with a...
  44. C

    Is the Distance Traveled by Light Affected by Time Dilation?

    When you derive the time dilation equation, and you see the light move straight down in one frame and in the other frame you see it move on a diagonal because the object is moving. My question is in the moving frame when you use the horizontal distance to derive the distance that the...
  45. I

    Can time dialation really just be the slowdown of physical processes?

    In special relativity physicists talk about time dilation, saying that as an object moves faster relative to another that its "clock" moves slower and therefore time slows down. Could it be fair to say that time doesn't actually slow down, but all matter and energy reactions slow down and...
  46. G

    Specific relativity Length Contraction and Time dialation question

    Special relativity Length Contraction and Time dilation question Homework Statement Planet X is 18 Light Years from earth, A spaceship moving towards the Earth at a speed of 0.82C (Measured from Planet X) fires a series of 1.2 cm long and 2.1 gram mass (as measured by the pilot) projectiles...
  47. Artlav

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    Good evening. After reading about the recently created record-breaking precision quantum clocks i got thinking about how gravity affect time. Suppose we have two clocks that are precise enough to register the gravity-induced difference of time rates at distances of a few meters up/down...
  48. J

    Will two clocks be synchronized after a period of time dialation?

    As 2 time pieces are moving relative to each other in a non accelerated reference frame, they will both see the other as slow. As time goes on, the amount of observed error in the other clock will continue to grow greater and greater. Let's say that after a while both clocks are 10 hours ahead...
  49. O

    Schwarzschild Radius, Constantcy of Light speed, and Time Dialation

    First off, I'd like to point out that I am by no means an expert in this area, and I am only doing some casual research as a personal interest topic, and have some further unanswered questions that I'm unable to find reasonable answers for. These questions are all inter-related, so I'll post...
  50. P

    Time Dilation: 1.25yr Trip at 2.40x10^8m/s

    An astronaut is traveling at a constant speed of 2.40x10^8 m/s relative to Earth through space. according to timing devices aboard the space vehicle the trip took 1.25 years. how long did the trip last if measured relative to earth HELP PLEASE!
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