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programming numerical algorithms for astrophysical applications.


Nov
9
comment Number density of stars on the Galactic plane
The stellar halo is definitely not appropriately described by a vertically exponential, but by a (galactocentric) radial power-law. Also, for most disc populations, $\mathrm{sech}^2(z/h)$ gives a better description than the exponential, but these are details.
Oct
19
awarded  Revival
Oct
8
answered What happens if two galaxies collide very quickly?
Oct
8
revised What known comets are binary?
added 4 characters in body
Oct
6
comment Is there any way a meteor can hit at less than escape velocity?
@LDC3 clarified in answer, but this was already evident from the question. Did you vote this down??
Oct
6
revised Is there any way a meteor can hit at less than escape velocity?
added 290 characters in body
Oct
5
answered Is there any way a meteor can hit at less than escape velocity?
Oct
5
comment What causes jets from newly born stars?
be honest upfront: "I/we don't know"
Oct
5
comment What are the current observational limits on the existence of Dyson spheres/swarms/rings?
No serious astronomer does. Those who do, do only because they can market that well with the public and hence get some funding.
Oct
4
comment What causes jets from newly born stars?
It's not clear from your answer why the magnetic field would create jets.
Oct
4
comment What are the current observational limits on the existence of Dyson spheres/swarms/rings?
I think a Dyson sphere is impossible, because nothing can stabilise it against gravitational collapse into the star. A ring rotating at the right rate is better, but a completely different type of thing and can only capture a tiny fraction of the stars energy.
Oct
4
answered If the expansion of the universe is speeding up, how long until everything nears the speed of light, and what would happen?
Sep
24
awarded  Autobiographer
Sep
18
revised How fast is a comet moving when it crosses Earth's orbit?
added 162 characters in body
Sep
18
comment How fast is a comet moving when it crosses Earth's orbit?
who is Wolfram?
Sep
18
answered Did cosmological inflation occur at speeds greater than $c$?
Sep
18
answered How fast is a comet moving when it crosses Earth's orbit?
Sep
16
comment What are the biggest problems about the numerical, finite-element GR models?
Perhaps, this sort of calculation is not so interesting (compared to QCD). What has been done is the merging of two BHs (including the gravitational radiation and the resulting anisotropic effects)
Sep
15
comment What is the difference between Sphere of Influence and Hill sphere?
@HDE226868 Excellent spot! Unfortunately, this is on another stack exchange site, so we cannot close this as a duplicate. However, duplicating the answer is clearly not worth the effort.
Sep
15
reviewed Approve Time-density and time-temperature functions of the Universe since the Big Bang