Skip to main content
Physics

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

5
  • $\begingroup$ You can't really apply Newtonian mechanics to positronium. A far better example would be a binary star, or a system like Pluto and Charon. $\endgroup$ Commented Oct 2, 2016 at 17:11
  • $\begingroup$ Indeed, for that one needs QM to get the orbitals and QFT (QED) to get the annihilation. Binary stars might be problematic due to gravitational waves. I added the concerns to the question. $\endgroup$ Commented Oct 2, 2016 at 17:22
  • 1
    $\begingroup$ The effect of gravitational waves on binary stars is almost completely negligible. We've only measured orbital decay for one binary star system, and they're not going to to collide any time soon. $\endgroup$ Commented Oct 2, 2016 at 17:32
  • $\begingroup$ Thank you all! Can I say that all the orbits are cone sections, but only the orbits of m with M>>m (for 2 bodies) can be deduced by using reduced mass system? If so, can you let me know how people derive e.g. the orbits of the binary star system (not including gravitational waves and relativity)? Do you have any good books to recommend? $\endgroup$ Commented Oct 3, 2016 at 3:31
  • $\begingroup$ The orbits are always cone section in the relative coordinate system. You can solve the system there and then transform the coordinates back again with $x_1 = R + r/2$ and $x_2 = R - r/2$ where $x_1$ and $x_2$ are the coordinates of the two masses, $R$ is the position of the center of mass and $r$ is the relative displacement vector. $\endgroup$ Commented Oct 3, 2016 at 12:05