All Questions
88
questions
28
votes
2
answers
10k
views
How long until we fall into the Sun?
As a planet moves through the solar system, a bow shock is formed as the solar wind is decelerated by the magnetic field of the planet. Presumably the creation of this shock wave would cause drag on ...
- 16.6k
5
votes
2
answers
9k
views
How would gravity change on a planet rotating around itself very fast?
Let's take a planet identical to Earth, but with rotation speed multiplied by ten thousand. What would happen with the gravity if it was spinning madly around itself? Would the centrifugal force make ...
- 1,281
4
votes
1
answer
185
views
Link between Earth and Mars
I am trying to the calculate the link budget for link between a ground station on Earth (with a particular latitude and longitude) and a rover at a particular location on the surface of Mars, either ...
- 41
16
votes
1
answer
548
views
Relationship between Mars and Earth rotation
Is it by pure random chance that Mars and the Earth have nearly the same day duration (Mars day is barely 40 minutes longer, which is just 3% difference), or there is some causal relationship between ...
- 14.5k
4
votes
2
answers
584
views
Does the Earth have a semi-solid body at its core because of lower pressure at the center of the Earth?
I have read that the Earth has a semi-solid iron body at its core, even though that object is surrounded by liquid magma.... I'm wondering if this is because of a pressure (and resulting temperature) ...
- 141
4
votes
2
answers
5k
views
How does one measure Earth's speed of revolution around the sun?
I know that there are several formulae that one can plug numbers into to arrive an estimate of Earth's speed around the sun (Kepler's third law for instance), but I'm wondering how these things are ...
- 3,727
6
votes
2
answers
10k
views
What does the phrase "limb of the earth" or "atmospheric limb" mean?
What does the term limb of the earth (see this question, for example) or atmospheric limb mean? The phrase strikes me as very odd, since earth is nearly spherical. Do other planets with atmospheres ...
- 199
1
vote
1
answer
1k
views
What equations/constants were used to calculate the Kármán Line for Earth?
I am interested in how the original value of ~100 km was calculated for the Kármán line of earth. What equations and constants would need to be used to reproduce this value?
Note: By constants, I'...
- 113
10
votes
4
answers
3k
views
How do we know that Earth is not perfect sphere?
I've just read here that:
Equatorial radius = 6378.16 kilometers. Polar radius = 6356.78
kilometers, so the difference in circumference is 71.1 kilometers. It
is not a perfect sphere, but kind ...
- 213
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
6
votes
1
answer
429
views
Axial tilt and precession rate of exoplanets
The Earth's axis is 23.5 degrees away from othogonality to the ecliptic, and it takes about 26 000 years for it to precess fully. I have neither an intuitive sense nor the formula for precession ...
- 9,547
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
11
votes
6
answers
10k
views
What sustains the rotation of earth's core (faster than surface)?
I recently read that the earth's core rotates faster than the surface.
Well, firstly, it's easier to digest the concept of planetary bodies, stars, galaxies in rotation and/or orbital motion.
But, ...
- 1,187