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Apr
18
comment Magnetar and black hole
what do you think?
Apr
14
comment Can stars be observed from space by x-rays, near infrared and radio wavelengths?
No, "seen" implies the human eye, which is incapable of sensing in these wavelengths. Or didn't you mean that?
Apr
12
answered Can we know the orbital planes of extraterrestrial planetary bodies?
Mar
10
revised What is the term for astronomical objects outside the solar system that are smaller than dwarf planets?
added 387 characters in body
Mar
9
answered What is the term for astronomical objects outside the solar system that are smaller than dwarf planets?
Feb
27
comment Fourier Transform of Galaxy Images
The Fourier transform per se will not help you to find overlapping object. Where does this idea come from?
Feb
27
answered Is gravitational energy released when a body contracts?
Feb
18
awarded  Nice Answer
Feb
6
answered How do moons get captured?
Feb
6
answered Why there are other planets in our solar system?
Feb
6
comment Why there are other planets in our solar system?
Are you asking for the reason (that there are planets) or for their purpose?
Feb
6
comment Why there are other planets in our solar system?
Why are there other people on this planet. Only I am important. What is the significance of others, such as user804401? I receive food from the plants and animals. In a similar way do I receive any food from other people?
Feb
6
comment Does one need to take into account finite gravity speed in N-body simulations?
Most large-scale N-body simulations (e.g., stellar clusters, galaxies, galaxy clusters, ...) use general relativity Wrong For up to galaxy scales, one safely uses Newtonian gravity. For larger scales (so-called cosmological $N$-body simulations), one uses GR only to describe the (assumed) smooth background (universal expansion), but Newtonian physics otherwise.
Feb
6
revised Why are all quasars so far away?
added 122 characters in body
Feb
6
comment Galaxy rotation curve and dark matter
The authors of that book should have mentioned the caveat, that it only introduces a small error, and that in the scientific literature (of which that book is no part) such simplifications are not made (unless the errors introduced are far smaller than other sources of error). If they did not, then this is just another example of poor practice in presenting science to the public.
Feb
6
revised Galaxy rotation curve and dark matter
added 480 characters in body
Feb
5
answered Galaxy rotation curve and dark matter
Feb
5
comment Galaxy rotation curve and dark matter
Can you substantiate your claim (that galaxy rotation curves are calculated from what you call the shell theorem)? For near-spherical object, the error one makes with this assumption is very small (at most a few %).
Feb
5
answered Why are gas giants colored the way they are?
Feb
5
answered Why are all quasars so far away?