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Pauli exclusion principle - black holes
If a white dwarf compresses to the limit of electron degeneracy, and a neutron star compresses to the limit of neutron degeneracy, what does a black hole compress to the limit of?
scorpdaddy
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Are all satellites thought to be the result of collisions with the planets?
The leading hypothesis for how the Moon was formed was that another object collided with the Earth, throwing off a large lump of matter which formed into the moon.
Is this thought to be the case with all satellites? e.g. Phobos, Deimos, Charon,…
komodosp
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Are there ways to estimate size of the "whole universe"?
Words escape me, but by "whole universe" (I think) I mean everything that's spatially connected to the observable universe in a conventional sense. If there is a better term for it, please let me know!
I was surprised to find out that theories and…
uhoh
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Is there an optimum orbit for a Hipparcos/Gaia-like parallax observatory
The Gaia spacecraft is currently mapping the stars in the Milky Way by parallax. It orbits in the Earth-Sun L2 Lagrange point. The parallax observed from the spacecraft orbiting around the sun allows us to derive the distances to many stars in the…
Ingolifs
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A "strange" unit radio astronomy
I'm reading up on radio astronomy, and I came across this paper from 1964. At the bottom of page 193, the author uses a unit that I've not seen before in discussing radio power emission from stars:
Now the outbursts on the Sun give an intensity on…
Jim421616
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Beta Andromedae (Mirach) and distances mentioned in original Cosmos series from 1980
In one of the episodes from Carl Sagan's show Cosmos he explains that Beta Andromedae is the second brightest star in the constellation Andromeda, and is 75 light years away. The link to the video is here.
I've looked up this star on Wikipedia and…
Zebrafish
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How do we know that an exoplanet is tidally locked to the parent star?
Often in discussing exoplanets we hear that they are close to the parent star (usually a red dwarf) but then there's a caveat that the planet is tidally locked to that star and that that fact severely decreases prospects for that planet to harbor…
stackzebra
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How can gravitational lensing makes a quasar appear brighter?
How can gravitational lensing makes a quasar brighter than it would in the absence of a foreground galaxy?
Haris Ansari
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How does a star's rotation affect a star on the main sequence?
I searched and have found that the questions mainly focus on neutron stars, white dwarfs and black holes. This was not what I want.
Basically, the bigger the star's mass is, the more intense its fusion reaction is and the shorter its lifespan is in…
Christmas Snow
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Why haven't more captured small moons been found?
Shouldn't captured moons have the same size distribution as asteroids? And asteroids are more common the smaller size they are. Moons are likely captured if they are in highly inclined orbits, and those moons should've originated as asteroids or…
LocalFluff
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Why the blank wedges in this very early 21 cm map of the Milky Way? (Oort et al. 1958)
Jan Oort was a pioneer in radio astronomy. Wikipedia says:
It has been written that “Oort was probably the first astronomer to realize the importance” of radio astronomy. “In the days before radio telescopes,” one source notes, “Oort was one of the…
uhoh
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How does the Moon move in the "night" sky as seen from the poles?
A photo in the NYTimes article Ice Surveys and Neckties at Dinner: Here’s Life at an Arctic Outpost has got me thinking.
During the winter months at either the north or south pole, when it is constantly dark, how does the Moon behave?
Would a…
uhoh
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How much longer is this (July 27th 2018) lunar eclipse than others?
According to the BBC the lunar eclipse on July 27th/28th 2018 is the "longest this century".
Longest isn't a very good way of describing things, since it's a relative measure without reference to actual numbers, and implies it's somehow longer in…
Steve Sether
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What is the highest resolution image of the moon taken from Earth's surface?
According to this article:
https://www.theguardian.com/science/2018/jul/26/star-spotted-speeding-near-milky-way-black-hole-for-first-time
the Very Large Telescope is "powerful enough to see a tennis ball on the moon from Earth". I guess that the…
viggo
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Why moon sighted only in Kerala but not in rest of India?
I know for most of you the question may look silly, but Kerala is a state in India where the moon (Ramadan moon) will be sighted but not in rest of India.
I was reading the news article where I got a little hint but was not clear for me since I am…
goodyzain
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