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2h
reviewed Approve Does the Earth have another moon?
11h
revised What determines the configuration of orbits in a binary system?
Correction of mass order in explanation (result unchanged)
1d
answered What determines the configuration of orbits in a binary system?
1d
comment What is the orbit of Earth around the Sun?
@DheerajKumar Well, if you get down to it, orbits are elliptical because of conservation of the LRL vector and energy, and though one can show that LRL is conserved as a result conservation of angular momentum, in some hypothetical world it's possible for LRL to be conserved without angular momentum conservation. Orbits would still be elliptical in that case (Kepler's first law would hold), but Kepler's second law (equiv. to angular momentum conservation) would be broken.
1d
awarded  Nice Answer
1d
comment What is the orbit of Earth around the Sun?
@DheerajKumar There's nothing special at the second focus, but there's a derivation of how to find it at Why are orbits elliptical instead of circular?.
1d
comment What is the orbit of Earth around the Sun?
@DheerajKumar no, or rather, it's the center only in the case where the ellipse is a circle (a special case)
2d
answered Accretion disks - why are they disk-shaped, rather than spherical?
Dec
7
awarded  Organizer
Dec
7
revised Typical wavelength of solar flare
edited tags
Dec
7
answered Typical wavelength of solar flare
Dec
6
answered Exploiting symmetry in the axisymmetric Jeans equations
Dec
6
reviewed Approve Distance between Earth and where The Big Bang's happened?
Dec
5
comment Are our 'observations' of or near a black hole affected by gravity induced time dilation?
@TracyCramer: as explained in the answer, they would be redshifted.
Dec
5
comment Are our 'observations' of or near a black hole affected by gravity induced time dilation?
@TracyCramer since both emission and detection happened far away from the black hole, no, it's the frequency is not shifted.
Dec
5
answered Are our 'observations' of or near a black hole affected by gravity induced time dilation?
Dec
4
comment Are our 'observations' of or near a black hole affected by gravity induced time dilation?
Events are observed over a different period of time than when they happen, and thus in a different time frame (in the usual English vernacular sense). But that has very little to do with GTR, so what do you mean by 'time frame' in this context?
Dec
3
comment What is the long term fate of the gas giants?
@RobJeffries That's not an interesting argument without a better model, which is exactly what I'm asking for anyway.
Dec
3
comment What is the long term fate of the gas giants?
@RobJeffries Yes, that's why I said that it's uncertain to what extent the present conditions are indicative of Jupiter's actual long-term future. However, the point is that dismissing the internal heat generation without deeper analysis as if it were simply obvious is inappropriate.
Dec
3
comment Why does the distance between Sun and Earth stay the same?
@Walter I derive here if you want a www reference specifically. Otherwise, it's in MTW §25.5, Hartle §9.3, Carroll §5.4, and other textbooks, up to some notational differences (e.g., $V_\text{eff}^{\scriptsize\text{MTW}} = \sqrt{2V_\text{eff}^{\scriptsize\text{Hartle}}+1}$). By the way, I didn't notice that you used $L$ as specific angular momentum when I made my previous comment, so the $m^2$ term would be unnecessary.