All Questions
Tagged with newtonian-gravity planets
311
questions
7
votes
1
answer
3k
views
Radial fall in a Newtonian gravitational field [duplicate]
Suppose an object of mass $m$ starts at rest at a radial distance $ r_0$ from a perfectly spherical mass $M$ (where $m << M$), $r_0 > R =$ radius of $M$.
Can we analytically determine when ...
- 885
60
votes
4
answers
142k
views
How does gravity work underground?
Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole?...
- 703
3
votes
3
answers
296
views
How could they tell things weigh a sixth of their "Earth weight" on the moon?
I frequently keep hearing stuff about "gravity on the moon is only a sixth of that as Earth's" and "of course you'll weigh more on Jupiter". I do know the relative sizes of those bodies allow for ...
user758
9
votes
1
answer
680
views
Will Neptune change Pluto's orbit some day?
My seven-year-old son loves astronomy-- so much so that we read space books before bed time. One of our books talks about Pluto's orbit crossing over Neptune's orbit and will be (or is) closer to the ...
- 550
6
votes
2
answers
5k
views
Finding the position of a planet between two other planets of known mass and distance
Here is the question:
A planet with mass $m$ and a second with mass $M$ are separated by a
distance $d$. A third planet with mass $m_3$ happens to be midway
between $M$ and $m$. Where could the ...
- 237
13
votes
4
answers
2k
views
Two planets in same orbit - not planets?
Let us pretend for a moment that there are two identical planets that are exactly opposite their star from each other and are the same distance from said star. (This would make them, at all times, ...
- 1,057
25
votes
9
answers
28k
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Why are orbits elliptical? [duplicate]
Almost all of the orbits of planets and other celestial bodies are elliptical, not circular.
Is this due to gravitational pull by other nearby massive bodies?
If this was the case a two body system ...
- 1,374
19
votes
3
answers
4k
views
If it was possible to dig a hole that went from one side of the Earth to the other...
...And you jumped in.
What would happen when you got to the middle of the Earth? Would you gradually slow down, until you got to the middle and once you were in middle would every direction feel like ...
- 387
33
votes
3
answers
12k
views
Why does the Moon face Earth with the same side?
I know that the rotation period of the moon equals its revolution period. It's just so astonishing that these 2 values have such a small difference. I mean, what is the probability of these 2 values ...
- 495
39
votes
5
answers
34k
views
Would you be weightless at the center of the Earth?
If you could travel to the center of the Earth (or any planet), would you be weightless there?
- 543
22
votes
3
answers
7k
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Gravity on a doughnut-shaped/Möbius planet
How different would the effects of gravity be if the planet we're on is in the shape of a torus (doughnut-shaped)?
For an (approximately) spherical planet, it's slightly clear that objects would tend ...
user172