What is Lorentz contraction: Definition and 83 Discussions

Length contraction is the phenomenon that a moving object's length is measured to be shorter than its proper length, which is the length as measured in the object's own rest frame. It is also known as Lorentz contraction or Lorentz–FitzGerald contraction (after Hendrik Lorentz and George Francis FitzGerald) and is usually only noticeable at a substantial fraction of the speed of light. Length contraction is only in the direction in which the body is travelling. For standard objects, this effect is negligible at everyday speeds, and can be ignored for all regular purposes, only becoming significant as the object approaches the speed of light relative to the observer.

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  1. H

    What would actually be observed during Lorentz contraction?

    Greetings everyone, I understand the derivation of the Lorentz transformations, and have not had trouble applying the concepts and the math to most elementary SR problems. However, something occurred to me recently which I have been unable to resolve. Let’s say there are two tennis balls...
  2. M

    How Maxwell's equations explain the Lorentz contraction?

    I did more than one course of classical electromagnetism in college. Recently, however, after reading "How Relativity Connects Electric and Magnetic Fields" (http://galileo.phys.virginia.edu/classes/252/rel_el_mag.html) I was astounded to realize how little I knew about it! In college (if I...
  3. T

    Why does Lorentz contraction occur?

    My question is: why does Lorentz contraction happens? I have a understanding of this but I don't know if it's correct, so I'll tell what I understand, if I'm wrong please correct me... Suppose we have two observers A and B. If I say B is moving with respect to A then time is slower to B...
  4. S

    Special Relativity- Lorentz contraction

    Homework Statement Q1 http://www.maths.ox.ac.uk/system/files/private/active/0/b07.2_c7.2.pdf Homework Equations The Attempt at a Solution How do I do the final bit that lead to the discrepancy and why does this occur? I have no idea where to begin.
  5. T

    Length contraction or Lorentz Contraction

    As I understand it, Lorentz Contraction states an object "contracts" relative to it's velocity to an observer. So at a high velocity of speed, the meter stick (carried by the object moving relative to the observer) appears to contract (to the observer) and the observer measures less distance...
  6. W

    Proving No Length Contraction in Lorentz Transformation

    Homework Statement Hello, Consider a rod of proper length l_{0}. Prove/Show that there is no length contraction if an observer moves perpendicular to the direction of the rod. Homework Equations l = l_{0}/\gamma where \gamma is the usual relativistic vector The Attempt at a...
  7. Nabeshin

    What is the explanation for Death by Lorentz Contraction?

    I have recently been reminded of a problem a friend posed to me many months ago in special relativity that I was never able to address: Suppose we have a person inside a moving spaceship of proper length L. According to an observer outside the ship, the person inside the ship is at rest...
  8. E

    Lorentz Contraction Circular Motion

    Does Acceleration affect Lorentz contraction? Suppose their was a Circle spinning around its center then its outer edges would decrease in length. looking somewhat similar to a saw blade or something. This doesn't make sense though because then then object would change shape depending...
  9. R

    Lorentz Contraction: What really Contracts?

    OK I've been reading up on Lorentz contractions in special relativity and i have been wondering about something for a while now. When a Lorentz contraction occurs what actually contracts? the space between the atoms? (because we are 99% space) the actual atoms themselves? or the distance between...
  10. T

    Lorentz contraction of a light pulse

    Suppose the earth, moon, and an extraterrestial observer(ET) are at the corner of an equilateral triangle. The Earth observer points a laser at the moon and emits a powerful laser pulse for exactly .01 seconds. The 1,860 mile long pulse travels to the moon in about 1.3 seconds. The ET knows that...
  11. U

    Lorentz Contraction: Explaining the Mystery

    I don't understand why this happens. And it's not enough to tell me 'well it happens because Simultaneity is relative' or 'Because Time dilates between frames'. I can still say I don't understand why it happens because shouldn't 2 frames adjust their measurements so that they get the same...
  12. M

    Lorentz Contraction: Exploring Standard Relativity & Bell's Paradox

    I think I am correct in saying that Lorentz relativity and standard SR are experimentally indistinguishable. I think it is also the case that in the first, the space between objects does not contract while in the second evrything inclding space contracts pro rata. As a personal choice I prefer...
  13. N

    Reciprocal Lorentz Contraction Mismatch

    Consider two groups of 3 spaceships each. The groups are numbered 1 and 2. The ships in group 1 are numbered 1A, 1B and 1C. The ships in group 2 are numbered 2A, 2B and 2C. In each group, ship A leads, followed directly in line, at fixed and equal proper intervals (as measured in each line's...
  14. N

    No SR time dilation without Lorentz contraction

    My understanding is that SR time dilation and Lorentz contraction are flip sides of the same coin. The two always occur together, never separately. That is implicit in spacetime diagrams. I think this duality requirement is necessary so that light always travels at the speed of c in every...
  15. T

    Lorentz contraction at relativistic speeds

    So I was reading up on the SR equations and the following thought experiment crossed my mind: Suppose you have someone in a starship traveling at high enough speed to make the Lorentz factor noticeable. Will that produce a blurring effect when the observer is looking out the front window? I...
  16. B

    Lorentz contraction and simultaneous detection of the ends of the moving rod?

    It is known that with the formula that accounts for the time dilation effect in hand we can derive directly the formula that accounts for the length contraction effect: L0/Dt=L/(Dt)0 (1) where L0 and (Dt)0 are proper length and proper time intervals, L and Dt...
  17. M

    Lorentz Contraction and Chalk Guns

    Homework Statement This is actually an exam problem, not a homework problem. The solution have been posted, but I don't understand the solution. Here is the question, as posted: A very long rod travels parallel and very close to a flat surface in our laboratory. The surface contains...
  18. B

    Lorentz Contraction with small velocity

    Homework Statement About how many femtometers shorter than its rest length is the length of a car measured in the ground frame if the car is traveling at 30 m/s in that frame? Assume for the sake of argument that the car's rest length is 5.0 m. Remember that 1 fm = 10^-15 m. Homework...
  19. T

    Question on both Time Dilation and Lorentz Contraction

    Hi guys, There's a couple questions that I've been trying to figure out that I have not been able to make much progress on. 1. Time Dilation the equation states that T' = Lorentz Factor * T0 So the Lorentz factor will always be > 1 because v < c So then, if, let's say, there's 2...
  20. L

    Lorentz Contraction and Mass Distortion Calculation- Did I do this right?

    Hello, I recently learned of the Lorentz contraction and mass distortion effect in a physics book, and for the sheer heck of it, I decided to see what it would be like if my dog, Little Ann, were sped up to relativistic speeds. I decided to try to calculate it using the equations provided by...
  21. X

    Lorentz contraction of box filled with gas

    Consider what happens when we accelerate a box filled with gas. We have to expend a certain amount of energy to accelerate the box, In Newtonian mechanics, this energy goes into the kinetic energy of the box: as its speed increases so does its kinetic energy. This happens in relativity too, of...
  22. B

    Lorentz contraction from space-time interval invariance

    Please tell me if it is possible to derive the formula which accounts for the Lorentz contraction from the invariance of the space-time interval. Thanks
  23. O

    De Sitter relativity and Lorentz contraction

    De Sitter relativity and Lorentz contraction I need help in understanding the elements of a paper that I think could turn out to be quite important, namely http://arxiv.org/abs/0711.2274 de Sitter Relativity: a New Road to Quantum Gravity R. Aldrovandi, J. G. Pereira) Inter aliathey say...
  24. C

    Verification of the Lorentz contraction of the space

    question for the Lorentz's space contraction I imagin this thought experiment: a train which travels with the speed of light is trying to enter a tunel which has absolutely the same form and dimmension like the train's shape, as if the the train goes slowly with his regular speed it will enter...
  25. marcus

    LQG discreteness no conflict with Lorentz contraction

    My impression was that only misinformed people argue that LQG discreteness is in conflict with Lorentz invariance. This was resolved a long time ago, i thought. Does anyone disagree? Want to talk about it? Explain something to me that I am missing? http://arxiv.org/abs/gr-qc/0205108 Reconcile...
  26. B

    Lorentz Contraction in Supersonic Jets

    Homework Statement Supersonic jets achieve maximum speeds of about (3 *10^-6)*c. By what percentage would observe such a jet to be contracted in length? Homework Equations The equations for these this problem would be : 1/gamma= L(proper)/Length = 1/sqrt(1-v^2/c^2) ; beta=v/c The...
  27. T

    A Lesson on Lorentz Contraction

    ok so i have been assinged to do a 10-12 page written lesson on the lorentz contraction, the thing is that i know very very little about it(we will assume i know nothing about it) so what i was wondering if anybody around here knew anything about it and wouldn't mind offering a hand. If there...
  28. G

    Lorentz contraction inverse trouble

    why Lorentz contraction transformation in the direction of motion for the problem in michelson experiment was proposed, instead of length expansion in the direction perpendicular to motion. I think that too will give the same solution. I don't know i might be crazy and silly in this argument. I...
  29. A

    Lorentz contraction in Special Relativity

    Does the equation for Lorentz contraction stay exactly the same when quantifying the 'mass increase factor' at relativistic speeds? Further, when one moves at close to light speeds, the view of the surrounding universe seen from the ship is distorted into a circular window. Would the...
  30. S

    Lorentz Contraction of a Rotating Object

    Let's make it simple and suppose you have a very, very, perfectly sturdy record or something, and a record player that can spin it at enough RPMs to give the edge of the disk a speed that is a significant fraction of the speed of light. Since length shortens along the direction of motion...
  31. M

    Quantized Space & Lorentz Contraction in Loop Quantum Gravity

    Does anyone know how in LQG they avoid the contradiction of a smallest unit of quantized space and Lorentz contraction?
  32. P

    Is Lorentz contraction objectively real?

    Those who teach special relativity consider it a very important exercise to have students decide how to measure the length of a rapidly moving object. That's religious indoctrination and a wrongheaded approach to physics. The theoretical process that physicists talk about to measure the length...
  33. P

    Lorentz Contraction: A Misunderstood Phenomenon with a New Derivation

    I don't recall seeing this derivation anywhere but its probably somewhere in the relativity literature since most things are. A poster at sci.physics.relativity posted what he thought was proof that the Lorentz contraction doesn't exist. See the Fig. 1 in Lorentz Contraction - Version 2 --...
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