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Top Questions

26 votes
6 answers
6k views

Definition of a moon in an exam: "A satellite of a planet that *doesn't produce light itself but reflects it*" - is there relevance for the emphasis?

7 votes
3 answers
2k views

Distance of the Crab nebula and the speed of light

14 votes
2 answers
3k views

why is it impossible to infer the surface temperature of Venus by spectroscopy observation from earth?

28 votes
1 answer
5k views

Is the dark side of the earth protected from the risks of solar flares?

8 votes
5 answers
2k views

Does the escape velocity formula take into account how a gravitationally bound object's distance to its primary increases before coming back down?

4 votes
4 answers
4k views

What is the ring of light around the moon and which star seen near it?

11 votes
1 answer
5k views

Why did Theia create only one moon if it struck Earth?

9 votes
1 answer
3k views

Why did the dust between the planets disappear during the birth of the solar system?

3 votes
1 answer
2k views

Could the Methuselah star be evidence that there was a universe before this one?

4 votes
5 answers
3k views

Could the human body feel the sudden disappearance or end of a gravitational force?

9 votes
1 answer
1k views

Why would rocky earth-like planets be rare around white dwarf stars?

10 votes
1 answer
1k views

Is Venus' north towards Earth's south

4 votes
3 answers
974 views

Celestial "orbits"

5 votes
1 answer
1k views

Realistic description of a sunrise viewed from the asteroid belt?

4 votes
6 answers
403 views

Gravitational waves vs. "normal gravity"

2 votes
3 answers
283 views

Integration of Plank curve of the Sun

7 votes
1 answer
530 views

Is there a formula for calculating surface temperature of a rocky world based on atmosphere and solar input?

3 votes
1 answer
406 views

Radiation pattern of a GW source

2 votes
1 answer
359 views

How did the temperature of the solar system evolve?

3 votes
1 answer
511 views

If you are in a deep gravity well, where time goes by more slowly, do you see the unfolding of a cosmic event at a different rate?

-3 votes
3 answers
227 views

Can black holes even exist [if mass cannot be retained near the collapse threshold]?

1 vote
1 answer
163 views

A mysterious signal at 14.2054 µHz

5 votes
1 answer
423 views

Reasonable stellar body stats

2 votes
3 answers
129 views

How can Kerr black holes have a 'speed limit' to how fast they can spin?

4 votes
1 answer
147 views

Could a Martian observer witness the Moon's formation with naked eye?

4 votes
1 answer
219 views

Where can i find dark frames in the ESO archive?

3 votes
2 answers
128 views

Instead of a 4 meter diameter, 50 liter spinning pool of dangerous mercury, why didn't the ILMT just use an ionic liquid? Or gallium?

3 votes
1 answer
323 views

Extinction Level Event (Asteroid Impact Hypothesis) Likelihood Equation

2 votes
1 answer
311 views

If w bosons can create dark matter neutrinos by decay, can they also create dark energy?

1 vote
1 answer
165 views

Did I see a meteorite in daylight? (4.30pm on 11/6/23

0 votes
2 answers
145 views

Why do we not call black holes black stars or dark stars?

4 votes
1 answer
234 views

How long would we survive an approaching neutron star?

5 votes
1 answer
73 views

What are the effects of mass concentration along a planet's axis of rotation?

3 votes
1 answer
240 views

Are there any estimates of the Roche Limit for 152830 Dinkinesh?

3 votes
1 answer
157 views

Do the Galilean moons' orbits around the Sun have loops (i.e. have concave parts)? And if so, how can their orbits be graphed?

3 votes
2 answers
113 views

Spiral Galaxies

4 votes
2 answers
140 views

Are there naked eye binary stars with periods less than 100,000 years?

3 votes
1 answer
108 views

Is an earth-sized moon orbiting a super-earth feasible?

3 votes
1 answer
100 views

How much mass did the Late Heavy Bombardment add to Mars?

1 vote
1 answer
130 views

How close can Venus be to the sun in the sky and still be visible to the naked eye?

1 vote
1 answer
78 views

Can you identify the source of this image of the Pacman Nebula (NGC 281)?

2 votes
2 answers
71 views

Size of the solar system relative to exosystems

1 vote
1 answer
67 views

Plotting scatter graphs with fits binary file?

0 votes
1 answer
105 views

If 42000 Starlink satellites interfere with telescope observations from Earth would someone observing from another solar system detect them too?

1 vote
1 answer
76 views

Why does the metallicity of stars decrease with increasing galactocentric radius and height above the galactic plane?

-1 votes
1 answer
95 views

What is the distance between Stephenson 2-18 and Earth?

1 vote
1 answer
91 views

sideways crescent moon but also no moon somewhere else?


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