# Time dilation and length contraction

Time Dilation and Length Contraction Time Dilation The most important and famous results in Special Relativity are that of time dilation and length contraction. Here we will proceed by deriving time dilation and then deducing length contraction from it. It is important to note that we could do it the other way: Whereas with proper time, all frames agree that the the accelerated twin in the twin paradox aged less than the inertial one. I just said that the age of the astronaut on arriving at the exoplanet can be accounted for in different ways depending on what frame you use.

If you use only the astronaut frame, the coordinate distance is The reason is that you can travel back and forth in space but not in time. In turn, this is related with an asymmetry between time and space in relativity, not in the laws of motion, but in the theory itself: If they could, then length contraction could be made permanent.

Why could you make length contraction permanent if you could move backwards in time? To see why you need to travel backwards in time remember the twin paradox: This result appears puzzling because each twin sees the other twin as moving, and so, according to an incorrect naive application of time dilation and the principle of relativity, each should paradoxically find the other to have aged more slowly You can explain why the twin paradox breaks the symmetry, that is, make the time difference permanent for one of them, by watching the figure below.

There the twin traveler changes of inertial reference frame in the middle of the trip to initiate its return. In the graph the change in speed is instantaneous, thus the acceleration infinite and the brake in the asymmetry instantaneous: If the change in speed were not instantaneous, then we would see that a small time segment that is, during acceleration in the traveling twin maps into a much larger time segment in the stationary tween, so the stationary twin will be correct.

Thus, to make length contraction permanent you need, instead of a traveler in space, a traveler in time. It should work like this: But now one of the meters meter two moves with traveler two. In the travelers reference frame meter two will be larger than meter one.

The same will think the stationary meter, meter one, who will think he is longer. Same when he is in a different reference frame when returning. No symmetry break for now. But if the traveler is allowed to move back in time when returning, a similar asymmetry than in the twin paradox will occur.

The final result being that the stationary meter was correct, and the returning meter will be shorter than the original.How Do I Know When to Go to the Hospital? When you think you are in true labor, start timing your contractions.

To do this, write down the time each contraction starts and stops or have someone do. Give a unique perspective on time. Give a new definition to time. Show the cause of time.

Explain the physics of time.

## SparkNotes: Special Relativity: Kinematics: Time Dilation and Length Contraction

Explain the cause of time dilation in gravity and with motion. Explain the twin paradox, explain the cause of length contraction, explain why gravity is only attractive? Feb 09,  · I had a quick question about Time Dilation and Length Contraction.

Are the two just different ways of measuring/describing the same effect? Or rather they both. Time Dilation, Length Contraction and Simultaneity: An animated introduction to Galilean relativity, electromagnetism and their incompatibility; an explanation of how Einstein's relativity resolves this problem, and some consequences of relativity for our ideas of time, space and mechanics.

A summary of Time Dilation and Length Contraction in 's Special Relativity: Kinematics. Learn exactly what happened in this chapter, scene, or section of Special Relativity: Kinematics and what it means.

Perfect for acing essays, tests, and quizzes, as well as for writing lesson plans. Sep 30,  · In , Einstein put forth his theory of special relativity, noting that the failed Michelson-Morley experiment and the phenomena of length contraction and time dilation would all be explained if.

Time Dilation, Length Contraction and Simultaneity (from Einstein Light)