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programming numerical algorithms for astrophysical applications.


Sep
2
revised Determining effect of small variable force on planetary perihelion precession
major re-write, adding change of periapse
Sep
2
revised Determining effect of small variable force on planetary perihelion precession
re-organised the algebra
Sep
2
revised Determining effect of small variable force on planetary perihelion precession
deleted 10 characters in body
Sep
1
answered Determining effect of small variable force on planetary perihelion precession
Sep
1
comment Determining effect of small variable force on planetary perihelion precession
What confuses me here is the word "transverse". I think what you mean is 'azimuthal' (or perhaps 'tangential'). For me, transverse means "perpendicular to the direction of motion", but that's quite different from what you meant.
Sep
1
comment Determining effect of small variable force on planetary perihelion precession
There is a difference between your question here and that on mathematics (and physics): here the transverse acceleration is proportional to the radial acceleration and $K$ is a dimensionless number, there the radial acceleration has no effect on the transverse acceleration and $K$ must be an acceleration (though you talk about a 'number').
Sep
1
comment Determining effect of small variable force on planetary perihelion precession
Yes, there are approximate analytical methods (perturbation theory), valid in the limit of $K\ll1$. Perhaps you can clarify your question a bit. What's the direction of the transverse acceleration (I understand 'transverse' to mean perpendicular to the instantaneous velocity, but it's not clear whether the acceleration is in the plane of the orbit or perpendicular or a mixture).
Aug
29
comment What is the relative time difference between us and a star system in outer layer of our galaxy?
This plot is not the rotation curve of the Milky Way, which is less accurately known (mainly because we are observing it from within, making these type of measurements difficult).
Aug
29
answered What is the relative time difference between us and a star system in outer layer of our galaxy?
Aug
28
comment Why do (most of) the planets rotate counterclockwise, i.e. the same way the Sun does?
Well, I'm not actually very well informed, so don't quote me on this.
Aug
28
awarded  Custodian
Aug
28
reviewed Reject suggested edit on Are there stars that don't emit visible light?
Aug
28
answered World line coordinate finiteness
Aug
28
answered Are there stars that don't emit visible light?
Aug
28
answered Can the Gaia telescope detect small temporarily captured asteroids near its Lagrange orbit?
Aug
27
comment Determining effect of small variable force on planetary perihelion precession
Are you still seeking an answer?
Aug
27
comment Is there a paper on galaxy mergers in clusters of galaxies?
+1 good question. I cannot provide an answer, but in general merging in clusters is rather rare (because the galaxies' mutual velocity is $\sim1000$km/s, much higher than their own velocity dispersion), in contrast to galaxy groups. On the other hand, the central cluster galaxy is almost certainly a merger remnant, but may have merged before the cluster was established. Minor merging activity onto the central cluster galaxy is presumably common.
Aug
27
comment Why do astronomers like green laser pointers?
@abelenky A laser pointer is not astronomical equipment. Lasers are also used in astronomical equipment, for example in artificial guide stars for adaptive optics, but this was not the question.
Aug
26
revised Can we see the Big Bang happen if we look far enough?
reply to a comment
Aug
25
revised How do black holes evaporate?
corrected typo in title