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1500 questions
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Why are asteroids so much richer in precious metals than Earth's crust?

Did the majority of Earth's precious metals sink below the crust during Earth's formation?
zucculent
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Is the scaling in this composite photo of the moon and the Andromeda galaxy reasonably correct?

SEE BJV EDIT BELOW. I came across this image which purports to show what the size of the Andromeda galaxy would be in the night sky if we could see its dim stars with the naked eye. Is this image reasonably correct with respect to size? EDIT BJV…
BradV
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Have we observed any static neutron stars?

Neutron stars are one type of remnant of a giant star's core after its collapse. Neutron stars tend to rotate at very high speed and the mismatch between its axis of rotation and magnetic pole make it a "pulsar". Over time, the rotational energy is…
Kavin Ishwaran
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Is it possible that a star is the center of a galaxy?

I read that the black hole at the center of the galaxy has much less mass than the galaxy itself and that it is somehow held together by dark matter. So now I am wondering if it is possible that there are galaxies with a star at the center?
Mice0x
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How are radio telescopes pointed?

In the past, I worked as a programmer in a radio astronomy station, and since then I have a question on my mind. To observe a star with a telescope, we locate its location with our eyes and then we try to point the telescope using our eyes. We…
Aminos
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Can a star undergo helium fusion after depleting all its hydrogen?

For stars around the mass of the sun, helium fusion occurs concurrently with late hydrogen shell burning. For stars smaller than the sun, is their a subset that first burn all their hydrogen store before initiating helium fusion in their cores? Is…
H2Forge
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What is the mass of hotspots in the Cosmic Microwave Background radiation?

A lot of pop science articles (for example, this Space.com article) discuss the cold spots on the WMAP data of Cosmic Microwave Background (CMB) radiation, but have any studies been done on the large mass of hot spots on the right of the image…
called2voyage
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Could Neptune be viewed with the naked eye from Uranus?

Which star or planet in our night sky can match what Neptune would look like when viewed from Uranus, or one of its moons? The answer would be for the most favourable condition, which is when Neptune and Uranus are closest to each other.
Constantthin
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Why is the L3 Lagrangian point not perfectly stable? And why is the Earth-Sun L3 point a bit less than one A.U.?

I suppose the answer might involve general relativity, but still.... The L4 and L5 points are considered, theoretically, long-term stable, but not L3, on the exact opposite side of the Sun... And it is not, apparently, located exactly one A.U. from…
Kurt Hikes
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Is there a better formula for gravitation, besides Newton's?

Many experiments (e.g. changes in Mercury's orbit) show that Newton's Law of Gravity is not exact. According to the theory of relativity, what is the exact formula?
Kavin Ishwaran
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Radius to which all hydrogen-burning stars are known?

For the purposes of this question, I wish to consider active, hydrogen-burning stars, not deuterium-burning brown dwarfs, or stellar remnants like black holes or neutron stars. (Though including those would be interesting questions in and of…
notovny
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Why do gravitational waves travel "only" at the speed of light but the gravitational scalar potential is instantaneous?

To my old Space SE question Besides retarded gravitation, anything else to worry about when calculating MU69's orbit from scratch? @DavidHammen's excellent answer replies that one should not add a time delay to gravitational effects based on…
uhoh
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Is oxygen an alpha element?

Type II (core-collapse) supernovae occur shortly after star formation and enrich a galaxy with $\alpha$ elements such as O, C, NE, Mg, Ca and Si. On the other hand, Type Ia supernovae occur on a more delayed timescale and produce mostly Fe and…
quantumflash
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What are the benefits of collecting asteroid samples in situ rather than just waiting for bits of asteroids to fall as meteorites?

Hayabusa and Hayabusa2 are sample return missions from asteroids. But little bits of asteroids fall to Earth all the time as meteorites. Why can't we just study those? What are the advantages of going to get a sample off the surface of an asteroid?…
usernumber
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Are Brown and Sub-Brown Dwarfs secretly more common than stars?

I recently heard that Red Dwarfs are the most common type of star, and low-mass Red Dwarfs are the most common type of Red Dwarf. This seems to imply a generic trend that the lower the mass, the more common the star. I have 2 questions. I know…
cowlinator
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