Contraction effects at relativistic velocities

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Discussion Overview

The discussion revolves around the effects of length contraction at relativistic velocities, particularly focusing on whether dimensions perpendicular to the direction of motion experience contraction. Participants explore various scenarios involving objects and ships moving at relativistic speeds, raising questions about simultaneity and the implications of relativistic effects on measurements.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether the perpendicular length of a rod traveling at relativistic speeds contracts, suggesting a need for clarity on the effects of velocity on dimensions.
  • Another participant presents a similar scenario involving two ships traveling parallel to each other, asking if the distance between them is subject to contraction.
  • Some participants assert that length contraction only occurs in the direction of motion, indicating that dimensions perpendicular to motion do not contract.
  • A participant introduces a hypothetical scenario involving a ship and guns on a planet, questioning whether bullets would hit the ship based on the timing of their firing as perceived from different frames of reference.
  • There is a discussion about simultaneity, with participants debating whether events that are simultaneous in one frame are also simultaneous in another, leading to differing conclusions about the timing of events as perceived by observers in different frames.
  • One participant references the Bell's Spaceship Paradox to illustrate how observers in different frames perceive distances and events differently, although this is contested by others who focus on the specific scenario of guns firing at a ship.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of length contraction and simultaneity, with multiple competing views presented. The discussion remains unresolved regarding the effects of relativistic velocities on perpendicular dimensions and the interpretation of simultaneity across different frames.

Contextual Notes

Participants reference various scenarios and thought experiments that highlight the complexities of relativistic effects, including the need for careful consideration of frame of reference and the nature of simultaneity. Some assumptions about the conditions of the scenarios are not fully articulated, leading to potential ambiguities in the discussion.

  • #61
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would gun A or gun B shoot first if they shot off at the same time according to the planet?
i know one of them shoots before the other. in which case, instead of shooting off two guns, the planet launches a ship. i assume since both sides of the ship are being launched at the same time one side of the ship would take off before the other from the view of ship A.
 
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  • #62
bino said:
would gun A or gun B shoot first if they shot off at the same time according to the planet?
i know one of them shoots before the other.
According to who? See post #49. (The ship will say gun B fires first.)
in which case, instead of shooting off two guns, the planet launches a ship. i assume since both sides of the ship are being launched at the same time one side of the ship would take off before the other from the view of ship A.
I assume you mean that a large ship taking off vertically with thrusters at each end firing simultaneously according to the planet? Then, correct, the moving ship will observe the front thruster to fire before the back one. There are no "rigid" bodies in relativity.
 
  • #63
i was asking as if there were a ship that had one engine where gun A is and one engine where gun B is. both engines would be launching at the same time according to the planet. and since gun B fires before gun A then engine B would launch before engine A according to ship A. in which case the ship B would be taking off crooked according to ship A. right?
 
  • #64
i was asking as if there were a ship that had one engine where gun A is and one engine where gun B is. both engines would be launching at the same time according to the planet. and since gun B fires before gun A then engine B would launch before engine A according to ship A. in which case the ship B would be taking off crooked according to ship A. right?
 

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