Most Popular
1500 questions
12
votes
2 answers
Official registry of lunar placenames?
What's the definitive source for names of geographic objects on the moon?
Reason: As a computer graphics project I've rendered a scene based on LROC terrain data. I want to know what I'm looking at.
The most detailed atlas I can find online is this…
David Given
- 405
- 2
- 6
12
votes
1 answer
Has the great Andromeda Galaxy ever collided with any galaxies?
We know that the Andromeda Galaxy is moving towards the Milky Way and vice versa, so there will be a collision. Because of the vast space between them, the stars as they are defined will not themselves come into contact until much later if at any…
Isopycnal Oscillation
- 223
- 1
- 6
12
votes
1 answer
Why was this asteroid (4864 Nimoy) chosen to be named after Leonard Nimoy?
The asteroid 4864 Nimoy was recently named after Leonard Nimoy. It was discovered on September 2, 1988 so it went nearly 27 years without a name. Why was this asteroid chosen to be named after him? Were they trying to think of a name for it and…
duzzy
- 554
- 3
- 12
12
votes
1 answer
How do people measure the distance between the Earth and The Moon?
How do people measure the distance between the Earth and The Moon?
What methods were used? Where can I find the official data?
user3052801
- 123
- 1
- 4
12
votes
2 answers
Can there be an object with planetary discriminant between Ceres and Neptune?
The planetary discriminant is a measure of how dominant a body is within its region of the solar system. For (true) planets, it is $>10000$ and for dwarf planets it is $<1$. (See this answer to "How many planets are there in this solar system?"…
ThePopMachine
- 608
- 3
- 13
12
votes
1 answer
Does anyone know why three of Jupiter's largest moons orbit in 1:2:4 resonance?
Three of the first four moons ever discovered outside of our own planetary sphere of gravitational influence orbit in very close to perfect resonance. Europa's orbit is almost exactly twice as long as Io's, and Ganymede's is almost exactly twice as…
Mark Bailey
- 1,013
- 1
- 8
- 16
12
votes
5 answers
How do you define the diameter of the Sun
That is, it's twice the radius where the radius is from the centre of the sun to some edge. But what is that edge?
Bathsheba
- 223
- 1
- 7
12
votes
2 answers
Could Venus be a source of Earth's apparent overabundance of water?
I've watched documentaries about the solar system, where it is suggested that Venus once had oceans of liquid water similar to those that cover most of Earth today. Venus is now in a period of runaway greenhouse effect and has lost its oceans. …
db9dreamer
- 221
- 1
- 6
12
votes
2 answers
How are Galaxy Super Clusters Generated
I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am not mistaken some of these clusters seem to be…
apxcode
- 459
- 2
- 16
12
votes
1 answer
Is starquake unique to neutron star?
I read from somewhere that astronomer use X-ray to observe the "shaking" not to be confused with wobbling of a distant neutron star, I think it is similar to what geologist using microphone to detecting sound wave (vibration) inside the earth (no…
user6760
- 2,503
- 16
- 30
12
votes
2 answers
Can protoplanetary disks form main-sequence stars?
As has been pointed out by @Envite in the context of a more general discussion (see Generalised planets?), there seems to be a moderate possibility for protoplanetary discs forming main-sequence stars (MS stars).
Main argument here is that Jupiter…
Alexey Bobrick
- 2,699
- 16
- 25
11
votes
10 answers
What's the largest non-spherical astronomical object in the universe?
Some asteroids and comets are non-spherical. But is the nature of big things and gravity so that large things in the universe are always spherical? What is the biggest astronomical object in terms of volume out there that's not spherical?
Note:…
bogen
- 2,356
- 2
- 18
- 32
11
votes
1 answer
How exactly is the Initial Mass Function (IMF) calculated?
The Initial Mass Function (IMF) is the empirical function which describes the initial masses of a population of stars. My questions are,
1) What are the various IMF's which are used?
2) For each, what type of population do they describe? (e.g. -…
astromax
- 5,973
- 23
- 45
11
votes
2 answers
How do moons get captured?
A moon-sized object is running loose in the Solar System, perhaps after a planetary collision. As it approaches a planet, it's presumably following an approximately hyperbolic path. If it goes on past, it's still on the same hyperbola, on a curve…
David Garner
- 221
- 2
- 6
11
votes
4 answers
Can magnetism escape a black hole?
I know light, and practically nothing but gravity can escape a black hole. My question is: can magnetism escape a black hole?
A couple things that convince me it can are:
Jupiter's magnetic field shape compared with the jets that can come from…
Jonathan
- 4,385
- 2
- 25
- 50