Gravitational attraction of bodies

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Discussion Overview

The discussion revolves around the gravitational attraction between two massive bodies, particularly in the context of binary star systems. Participants explore the derivation of a position-time equation for the motion of these bodies under gravitational influence, while addressing the complexities of reference frames.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant presents a position-time equation derived for two massive bodies, noting that it simplifies the problem significantly.
  • Another participant questions the applicability of the derived equation, asking for clarification on the reference frame from which the result is valid.
  • A later reply clarifies that the equation is based on the perspective of either moving mass, assuming they are initially at rest with respect to each other.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the validity of the derived equation or its reference frame implications, indicating ongoing debate and uncertainty regarding the results presented.

Contextual Notes

The discussion highlights limitations related to the choice of reference frames and the assumptions made about the initial conditions of the bodies involved.

Nabeshin
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Hello! The stem from this problem came to me when I was pondering how to describe the motion of two massive objects feeling the others' gravitational attraction (i.e binary star systems or something like that). Well this got ugly fast so I had to simplify a lot of things, and I finally got an answer for one.

Considering two massive bodies, initially at rest, with respective masses of m1 and m2, I derived a position-time equation of:

x(t)=[tex]\sqrt[4]{x_{o}^{4}-6Gt^{2}(m_{1}+m_{2})}[/tex]

Some notes: This isn't a true position-time equation, because I couldn't figure out how to do it with respect to an outside reference frame (i.e x-y axis), so it is merely the distance between the objects. I can add work such as the solving of the differential equation if necessary.

Can anyone confirm this result? Perhaps add a comment or two that might help with the overall goal described above? Thanks!
 
Last edited:
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bump :cry:
 
Could you explain from whose frame reference your result applies ? For instance, your result might be correct for an observer situated in the line of sight between the bodies, and initially at rest wrt the bodies before they begin moving ( ie at t=0, nothing is moving ).
 
The answer is with respect to either of the moving masses, actually, if that makes any sense. Although, I assumed at t=0 nothing was moving with respect to the other.
 

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