All Questions
5
questions
2
votes
1
answer
75
views
Gravitational collapse - proof that energy dissipation is required?
As an undergraduate, I took a short course on astrophysics, where I encountered the Jeans mass. This is the critical mass for a spherical cloud of interstellar gas above which the cloud is predicted ...
- 317
0
votes
0
answers
61
views
How to calculate the total energy of a planet at rest?
Let's just say we have the Earth-Moon system isolated in space, with Earth at rest, and the moon orbiting it.
How can we calculate the total energy of Earth in such a case (Kinetic energy would be ...
10
votes
3
answers
2k
views
Under which conditions do two moving bodies start orbiting each other around their center of mass?
If two bodies are close, both will get attracted to each other and collide. Under what conditions will the two bodies start revolving around their common center of mass? I understand that such bodies ...
- 415
11
votes
4
answers
3k
views
Why does an orbit become hyperbolic when total orbital energy is positive?
I stumbled across this page describing the energy of a given object in orbit.
It describes 'total energy' as:
$$E_{k} + E_{p} = E_{\mathrm{total}} $$
where
$$E_k = \frac{1}{2}mv^2$$
and
$$E_p = \...
- 113
1
vote
1
answer
405
views
Energy diagram of a planet with fixed mechanical energy
Consider the following energy diagram for the motion of a planet about a star.
The centrifugal potential curve can be represented once I fixed the angular momentum $\vec{L}$ of the planet. To fix the ...
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