All Questions
973 questions
13
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2
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Is it possible for "gas moons" to exist?
Is it theoretically possible for there to be such a thing as a "gas moon" as opposed to a rocky one?
Do any laws or models specifically prohibit the formation of gaseous moons?
- 191
-2
votes
0
answers
67
views
When does a rocky planet stop being a rocky planet?
I am not aware of any well defined line between a rocky planet and a gas giant/ice giant.
There doesn’t seem to be a firm boundary and it seems like a very fuzzy concept.
This works okay for the solar ...
- 3,645
2
votes
1
answer
96
views
Correct form of apparent weight due rotation of Earth
I have come across two seperate formulae for the apparent weight/acceleration due to the Earth's rotation and the centrifugal force caused by it:
$g'=g-R\omega^2\sin^2\theta$
$g'=\sqrt{g^2-R^2\sin^2\...
0
votes
1
answer
95
views
How do I calculate the maximum possible atmospheric density/ surface pressure a planet can have?
I'm not entirely sure if this is the right stack but here goes.
I'm trying to design a fictional planet that has less gravity than Earth but I would like to give it an atmosphere as or even more dense ...
- 49
7
votes
1
answer
1k
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Why doesn't Mars's or Venus's axial tilt change without large moons, but Earth's is believed to?
It is claimed that the moon stabilizes the Earth's axial tilt, but Mars and Venus (and Mercury, too) are rocky planets without large moons. Why are their axes stable?
0
votes
1
answer
145
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What is gravitational pressure at a distance $x$ from center or Earth?
What is gravitational pressure at a distance x from center or earth. Assume earth to be spherical and with no atmosphere. Assume that earth has uniform density ,R is radius of earth and M is its mass.$...
-1
votes
1
answer
118
views
How does the scale height of a planet's air at temperature $T$ relate to how high a ball would go when launched up at RMS speed of an air molecule? [closed]
I shortened "atmosphere" to "air" to fit the whole question in the title.
The ball is of course launched in a vacuum (i.e. the atmosphere is first removed).
Is this question given ...
15
votes
5
answers
4k
views
Why does Earth have the largest mean density of all the planets in the solar system?
Browsing the density of the planets (and Pluto, Ceres, Sun and Moon) in the solar system, I observe that Earth is the one with the largest mean density: $5494 \ kg/m^3$. Is there a physical reason for ...
- 267
2
votes
1
answer
86
views
Can there be an exchange of angular momentum between a planet and its atmosphere/liquid layers?
Consider a fast spinning planet with no outer influences (no outer thermal and gravitational influences like a star)
Could there be an spontaneous* exchange of angular momentum between the planet's ...
- 3,374
0
votes
1
answer
127
views
Can there be wind and/or liquid currents driven by a planet's rotation?
Can the rotation of a planet alone provoke any kind of wind or liquid current?
Can the atmosphere, at least in some cases, have wind currents driven by the planet's rotation?
And can liquids also move ...
- 3,374
0
votes
0
answers
99
views
Mississippi river and the equatorial bulge [duplicate]
Because the earth bulges near the equator the source of Mississippi river, although above sea level is nearer to the centre of earth then its mouth, how can a river flow uphill ? Is it due to high ...
- 11
1
vote
0
answers
133
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What is the value of $g$ 1 meter off the center of Earth? [duplicate]
Newton’s theory suggests it’s close to zero, but what says GR?
Edit 1: It’s obvious that at the center it’s zero for both theories. The curvature explanation of GR could give a different answer around ...
- 19
0
votes
2
answers
323
views
Can two bodies be charged to escape Earth's gravity?
A random thought.
The picture that I have in my mind is that when two similarly charged bodies (Charges of very large magnitude) are kept closely, they will shoot away from each other and if they ...
- 43
0
votes
1
answer
199
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Doubt regarding reduction of earth's angular momentum [duplicate]
I was reading this textbook and in in, they stated that the earth's angular velocity was reducing due to frictional forces between the ocean water and the ocean floor and to compensate for this ...
0
votes
0
answers
93
views
What would happen if Jupiter’s upper atmosphere were suddenly blown away, exposing its core?
I recently watched a scene from the One Punch Man manga where a character sneezes and literally blows away Jupiter’s entire upper atmosphere, leaving the planet’s core exposed. That got me thinking — ...
