Questions tagged [astrophysics]
The application of physical theory to celestial systems such as stars, planets, galaxies, supernovae, and black holes. Astrophysics proper is concerned with explaining phenomena more so than making observations, the latter falling under the purview of astronomy.
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How do you build a small-scale neutrino detector? [closed]
*This question is similar to: Is a DIY neutrino detector feasible?. The difference between my question, and the old one is that the question is from over 8 years ago. Naturally, some of the answers ...
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Nuclear (astro)physics for relativists and field theorists
Lately I've become interested in compact stars and I would like to learn a bit about the nuclear physics that goes into them. However, I don't know anything about nuclear physics, except for a few ...
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Is the size of a black hole singularity smaller than a fundamental particle?
I am wondering about the size of a black hole singularity. We know that a classical black hole is infinitely dense. I am not asking about size of event horizon. I am asking about actual size of the ...
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Could dark matter be radiation pressure? [closed]
I watched Stephen Wolfram on a podcast explaining this idea last night. He said that dark matter could be explained as "spacetime heat". My contention is that stars and black holes trap a ...
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Question about the toroidal magnetic field in quasars and the role of an ergosphere
1) Introduction
Most of astrophysical bodies (in this context: formed stars, young stellar objects and black holes) produce or are immersed in a non-zero magnetic field $\vec{B}$. It is common, since ...
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Why Cepheids have Period Luminosity relation?
According to my astronomy teacher, Cepheids is a type of variable stars that has Luminosity-Period relationship:
$M \propto log(T)$
, where $T$
is the pulsation period of Cepheids.
But I have a ...
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Why is pressure in the outermost layer of a star lower than at its center?
I have done the math and I have obtained the hydrostatic pressure in a star is lower at the outermost layer of a star than in its center, where the pressure is actually maximum. Although the equations ...
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Does Kirchhoff's law of thermal radiation fail for optically thin sources?
A box made of any material with a small hole in it will give blackbody radiation. According to my textbook by ARNAB RAI CHOUDHURI, If you place an optically thick source of same temperature as the box ...
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What is emission line ratio?
As the header stated, what exactly is the 'emission line ratio'? Like, [O III]/Hβ or [Ne V]/[Ne II]. Recently I've been reading some research papers in astronomy and astrophysics pertaining to ...
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Is the radiation from closed boxes blackbody radiation irrespective of the material of the box?
Suppose I have a box made of silver at temperature T, in thermal equilibrium with the surroundings. Silver has very low absorptivity and hence it will have the same low emissivity to maintain thermal ...
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When do we talk about spaghettification or pancakification in black holes?
So I've been doing some research for a while now, and yesterday came across the video of PBS space time talking about what happens to quantum information in a black hole. In the thought experiment ...
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What is the difference between the virial radius, the total mass-energy density radius and the critical density radius for a galaxy?
For a regular spiral galaxy like the Milky Way, how are these concepts different from each other?
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Realistic black holes
If I understand the answers provided in this Link Why singularity in a black hole, and not just "very dense"?
Then the singularity at $r=0$ may just be a mathematical artifact, and may not ...
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Why are planets denser as you approach the center?
Gauss' law says that the net electric force inside a hollow, uniform, not rotating sphere is zero. Since gravity is also proportional to the inverse square of the distance, I assume this should apply ...
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Mass-volume relation for a star - explanation
In the game Universe Sandbox, I created a gas giant (made of pure hydrogen) and begun increasing its mass and watched how its radius changed and how it evolved into a star. While it was already a ...
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