Does Relative Speed Affect Gravitational Attraction?

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Discussion Overview

The discussion revolves around the question of whether relative speed affects gravitational attraction, particularly in the context of relativity and kinetic energy. Participants explore theoretical implications and measurements related to gravitational fields and tidal gravity.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that if they are moving towards a heavier person, the heavier person would have more kinetic energy and a stronger gravitational field, raising the question of whether the total gravitational attraction remains constant.
  • Another participant emphasizes that measurements of gravitational effects will yield the same results regardless of the observer's frame of reference, indicating that the concept of gravitational fields can be ambiguous.
  • A further elaboration is made on the nature of gravitational fields, comparing the gravitational field of a hyper-relativistic object to that of an impulsive gravitational plane wave, and mentioning the use of specific instruments to measure tidal gravity.

Areas of Agreement / Disagreement

Participants express differing views on the implications of relative speed on gravitational attraction, with no consensus reached on the topic.

Contextual Notes

The discussion includes ambiguities in the definition of "gravitational field" and the reliance on specific measurement techniques, which may not align with traditional Newtonian concepts.

Who May Find This Useful

Individuals interested in the intersection of relativity and gravitational physics, as well as those exploring advanced concepts in gravitational measurement techniques.

cragar
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If i am moving at a constant speed and i see someone moving towards me , According to relativity i can't tell if I'm moving or they are moving. But if the heavier person is moving towards me they would have more kinetic energy and a stronger gravitational field, then if i was moving and they were stationary. So would the total Gravitational attraction between us be constant.
 
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Regardless of whether you consider yourself as moving, or the object as moving, the measurements you can actually make will turn out the same.

The "gravitational field" of a hyper-relativistic object will approach that of an impulsive gravitational plane wave, similar to the way the electric field of a hyper-relativistic charge approaches an impulsive electromagnetic plane wave.

"Gravitational field" is an ambiguous term, in this case I am using it to mean tidal gravity, something you can actually measure (i.e. for example with a Forward mass detector, or a gravitational gradient meter (typically a rotating cruciform gravitational gradiometer) like those they use to survey for oil with.

http://www.bellgeo.com/tech/technology_theory_of_FTG.html

This is probably NOT what you're used to thinking of as the gravitational field, but if you consider the problem of the Moon's gravitational field effect on the Earth, you can perhaps see that we don't measure the Newtonian field directly, what we actually observe are time-varying tidal forces.
 
Last edited by a moderator:
Thanks for your answer.
 

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