Unanswered Questions
143 questions with no upvoted or accepted answers
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cross-matched SDSS-WISE catalog
Please where can I find cross-matched SDSS and WISE dataset for a machine learning project?
(Galaxy-star-qso classification task)
2
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84
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Would we know if the universe was rotating?
I was wondering what we would observe if the universe had a small rotation. My conclusion was that galaxies on the equatorial plane of the universe would be slightly more redshifted than galaxies than ...
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Why MIT's Benjamin Rackham says "nearby ultracool dwarf SPECULOOS-3" would look "purplish-red, spotted, and flaring" from an airless orbiting planet?
May 15, 2024 MIT News article Newly discovered Earth-sized planet may lack an atmosphere includes the following:
“We can say from our spectra and other observations that the star has a temperature of ...
- 30.7k
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Project Analog Hypothetical Planet
For my story Project Analog, I was wondering if a hypothetical planet (Let's call it Suria). It has the same size and conditions as Earth with the same axis, tilt, and rotation, as well as one moon. ...
CommunityBot
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1
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Comprehensive Stellar Evolution Article
Is there an article that comprehensively covers stellar evolution, from start to finish. I've found articles on this, one in an introduction to a stellar evolution model, and I am searching for more. ...
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2
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102
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What would the Big Crunch theoretically look/feel like?
In the Big Crunch theory, the expansion of the universe reverses, resulting in all matter contracting into a single point. Imagine you are alive at the time of this event. What would the sky look like?...
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What do you call a protostar with more than 10 solar masses?
PMS Stars with less than 3 solar masses are T Tauri stars, and PMS stars between 3 and 10 solar masses are herbig ae/be stars, so what do you call a star with more than 10 solar masses? Is there ...
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Hayashi Track vs Red Giant branch
Are the red Giant branch and the Hayashi track the same thing? After doing some research, I found some similarities between the two, such as both aree fully convective. However, the T Tauri phase does ...
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2
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Local anisotropies in the expansion of the universe and tidal forces...?
In the context of the large-scale structure of the universe, there can be local anisotropies (https://www.aanda.org/articles/aa/full_html/2021/05/aa40296-21/aa40296-21.html).
I understand from this ...
- 1,017
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25
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Deriving Faber-Jackson Relation from Milgrom's Law
I am reading Famaey & McGaugh 2011, a review paper on Modified Newtonian Dynamics. My question concerns bullet 3 in Sec 5.2, where the authors try to explain how Faber-Jackson Relation can be ...
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Determining Time Based on Arc Seconds
So our arc day starts at 20°41'32 which is midnight (0:00) and ends 24 hours later at 21°42'42. According to my calculations it traveled 0 degrees, 59 minutes, and 30 seconds or 3570 arc seconds in 24 ...
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85
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Question about a White Dwarf formula
I have a question regarding the White Dwarf radius formula given on wikipedia, in terms of what units I am supposed to use and what expected values of one variable would be.
https://en.wikipedia.org/...
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66
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Flux from the Sun on the Earth using the Stefan-Boltzmann law
What is wrong with this computation, plase? I am getting the result of 4291.65 W m^{-2} instead of 1361 W m^{-2}. Thank you very much
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Consistent values for density of galaxies between degree squared and steradian
I have a table of densities of galaxies :
Expected number density of galaxies for photometric survey per unit area and redshift intervals, $\mathrm{d} N / \mathrm{d} \Omega \mathrm{d} z\left[\mathrm{...
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24
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What would be the new Equation of motion if the magnetic field's origin is shifted from the origin of a co-rotating spherical polar coordinates?
The equation of motions due to the dipole magnetic force of a planet in a frame corotating with the planet and origin at the centre of planet assumed to be sphere components wise are given as below:
\...
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