Unanswered Questions
183 questions with no upvoted or accepted answers
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How well conserved is etendue in extreme gravitational lensing scenarios?
This excellent answer to Could dark matter exist in the Universe in the form of sufficiently dense objects? includes the following image and description:
Light from the background galaxy circles a ...
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Get the expression of probed volume between 2 redshifts
1) I can't manage to find/justify the relation (1) below, from the common relation (2) of a volume.
2) It seems the variable r is actually the comoving distance and not comoving coordinates (with ...
CommunityBot
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Kepler ellipse orbit fit issues
I am helping my high schooler with a research paper that uses PyAstronomy to fit the orbit of stars around Sag A. It isn't working because the angles (parameters Omega, omega, and i) seem to have a ...
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What fraction of matter is not bound to the galaxies, groups and clusters that we see?
We know that most of the matter in the universe has collapsed into galaxies and galaxies into groups and clusters and that a lot of matter is presently in clusters between the galaxies. But, what ...
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Semimajor axis variations in co-orbital moons
I've been playing with simulations of co-orbital bodies similar to Saturn's moons Janus & Epimetheus- horseshoe orbits where the two bodies are of comparable mass- and I'm seeing some very odd ...
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Different techniques for calculation of celestial bodies dynamics with different time-scales
Differential equations describing the dynamics of celestial bodies (rotation, nutation, precession and other effects) can be solved numerically, which makes it possible to study their general non-...
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Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow?
Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow? I mean is it mandatory for a jet to be emitted from an accretion disk?
If so, then why?
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What are some good books/online resources for astronomy problem sets?
I am currently studying for the international olympiad for astronomy and astrophysics (the syllabus can be found here: https://www.ioaastrophysics.org/syllabus/). I am currently using Carroll Ostlie's ...
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Simulate earth, moon, sun constellation with dates
I would like to simulate the three object distance, specifically the distance of the moon to both, sun and earth for further investigation into tide prediction.
What would be a good starting point ...
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Strength of core-envelope coupling in stars
For a star with a given Zero-Age Main Sequence (ZAMS) mass, as a function of metallicity how strongly is the star's core coupled to its envelope?
I understand that the core-envelope boundary is only (...
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362
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Generate probability skymap
I am trying to generate skymaps for a set of Fermi GBM triggers, containing the probability that a trigger originated in a given part of the sky. For each trigger, I have access to the RA, dec, error ...
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Keyerror: 0 while using astropy SkyCoord
I am facing a problem while using SkyCoord from astropy library. The scenario is as below,
I have read the data from a fits file into a pandas dataframe.
I have applied several quality cuts to the ...
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4
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Explanation for Planck 2018 temperature fluctuations strongest peaks
As it can be seen from Plank 2018 Cosmic Microwave Background temperature fluctuations data-
There are 3 sharp peaks at multipole expansions $\ell \approx 250, 550, 800 $. Also as multipole expansion ...
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How much more mass would Mars need to currently have enough pressure for liquid water and oxygen?
My question is whether Mars just about failed to meet the threshold or missed it by a lot. It's been dry for 3 billion years. How much bigger would it have needed to be to buy it that extra time? Let'...
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Cosmology : Formula for the bias of galaxies
first I have posted originally on the physics stackexchange but I have not had answers about my question, so I try my luck on this specific forum (if forums leaders want to delete the original post on ...
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