Questions tagged [planetary-science]
The multi-disciplinary study of the geomorphology, geology, chemistry, meteorology, oceanography, hydrology, astronomy and astrophysics of the planets and other objects within the solar system.
119
questions
25
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2answers
780 views
Why do some planets have lots of $\mathrm{N_2}$ and others none?
Earth, Titan and Venus all have large amounts of $\mathrm{N_2}$ in their atmospheres. (In the case of Venus it's a small proportion, but Venus' atmosphere is very thick, and the total mass of $\mathrm{...
13
votes
1answer
234 views
Why does Mars' experience an 'ice age' at high axis obliquity, when Earth experiences an ice age at low axis obliquity
This paper here goes into some detail about how Mars' experiences its own form of 'ice ages' on a quasi periodic basis driven by the wobbling of its axis. The main mechanism outlined is that the ...
13
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6answers
2k views
Are there any photographs of mountains without significant erosion (on Earth or otherwise)
I'm curious about how mountains on an airless world such as the Moon would look if you were standing on the surface and looking at them. There are plenty of artists' impressions, of course, but I'm ...
13
votes
1answer
243 views
Is Mars' mantle homogeneous or heterogeneous and what might this say about mantle convection?
A supervisor of mine made an off-hand comment about the fact that Mars used to have plate tectonics, and there is evidence that Mars used to have plate tectonics, however now it does not. The theory ...
22
votes
2answers
354 views
What properties must a rocky body possess in order to exhibit plate tectonics?
The Earth exhibits plate tectonics, but the other terrestrial planets do not (though Mars and Venus may have exhibited plate tectonics in the past).
What is "special" about Earth that allows it to ...
31
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1answer
3k views
What factors determine the number of Hadley cells for a planet?
We know (think?) that Earth has three Hadley cells per hemisphere, but from observing gas giants such as Jupiter, we see that they have many more cells. According to a link from a comment in this ...
12
votes
1answer
668 views
What causes “shallow” moonquakes?
It is thought that "deep" moonquakes are caused by tidal forces exerted on the Moon by the Earth and Sun. Some other sorts of moonquakes are thought to be caused by impacts, or by thermal expansion (...
8
votes
1answer
437 views
How does the amount of mass in an atmosphere affect the seasonal changes and dynamics of the planet's climate?
I was thinking about this question, which may turn out to be simple, about climate dynamics: How does the amount of mass in an atmosphere affect the seasonal changes and dynamics of the planet's ...
21
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1answer
2k views
Why do Earth and Venus have different atmospheres?
Venus appears to be the closest to Earth in mass, density, size, etc. - though they clearly have different atmospheres. Why do Earth and Venus have different atmospheres?
-5
votes
2answers
214 views
Is there another explanation than an asteroid/volcano for the extinction event on Earth millions of years ago?
This idea keeps on appearing in my mind, once in a million years the Sun's gravity will pull Earth near and eliminate every living in the earth due to the increased heat, and in another million years ...
1
vote
1answer
175 views
Is the majority of Earth not unique?
Realize that comparing planets is hard, but is Earth really that unique?
More to the point, if everything say 20-km below sea-level up into the exosphere disappeared (and the moon too) - what would ...
27
votes
2answers
2k views
Would the Earth function the same spinning the other way?
Right, I saw a question about why the Earth spins counter clockwise, and it reminded me of something I would like to know the answer to.
I watched a episode of Futurama. In this episode the Earth ...
8
votes
2answers
1k views
Why is earth's axis tilted?
Why is the axis of earth tilted? It can't possibly be that the Northern hemisphere is larger causing it to be pulled toward the sun, because then it would always be summer in the N hemisphere and ...
18
votes
3answers
29k views
Why does the earth spin clockwise?
Why does earth rotate in a clockwise direction? Did a large meteor collide with earth causing earth to rotate? If that is what happened, could another, larger meteor cause earth to reverse its ...
14
votes
5answers
2k views
Is Earth an organism?
According to Wikipedia, "all known types of organism are capable of some degree of response to stimuli, reproduction, growth and development and self-regulation via homeostasis." Further, watching a ...
14
votes
1answer
183 views
What kinds of remote sensing required to observe methanogenic life on Titan?
Inspired by Chris McKay's Possibilities for methanogenic life in liquid methane on the surface of Titan. In the paper, the PI's found that the consumed acetylene, ethane, and other organic solids ...
13
votes
1answer
220 views
Phase changes deep in planetary interiors and their implications for surface tectonics
Earth's core mantle boundary represents a phase change from a solid (though convecting) mantle to a liquid Iron/Nickel core. This dramatic transition is likely the origin of the D" boundary, as well ...
20
votes
4answers
12k views
Will the Earth ever stop rotating?
It is well known that the Earth's rotation is slowing down and that millions of years ago there was a point in time where there was only a mere 20 hours in a day on Earth.
My question is in two parts....
33
votes
5answers
7k views
How and why did the oceans form on Earth but not on other planets?
Earth is the only planet in our solar system that has copious amounts of water on it. Where did this water come from and why is there so much water on Earth compared to every other planet in the ...
