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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.

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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 ...
tux's user avatar
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8 votes
1 answer
991 views

What "g" would be needed to keep helium on Earth?

I know that helium is a very light and rare gas on Earth because Earths gravity is not strong enough to keep it. Instead, helium and hydrogen are rising through the atmosphere and escape into outer ...
Petr Hykš's user avatar
8 votes
1 answer
455 views

What are Ordovican trace fossils, and what do they look like?

There are some unusual structures in recent images from the Mars Curiosity Rover's MAHLI (Mars Hand Lens Imager) shown in the Space.com article Curiosity Rover Spots Weird Tube-Like Structures on Mars....
uhoh's user avatar
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8 votes
1 answer
535 views

How do tectonics work on other planets?

What kind of tectonic plate activity exists on other planets in the solar system, or even large moons? Are there any deeper studies of what is needed for a planet or large moon to have tectonic ...
Henry Stone's user avatar
8 votes
1 answer
723 views

What would happen if we removed Earth's moon?

This question is an object of fascination of mine. There are a few different angles to take to it. My favorite is blasting the moon out of existence while its moving away from Earth. What would ...
ethug's user avatar
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1 answer
531 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 ...
Neo's user avatar
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8 votes
1 answer
220 views

Melting basalt on the lunar surface - what would the resulting material be like?

The idea is to melt the fine-grain portion of basalt regolith using a large Fresnel lens, and let it cool to a solid. The lens would track along a tamped bed of material leaving a molten puddle ...
kim holder's user avatar
8 votes
2 answers
741 views

Why is the mass of atmosphere of Venus so much greater than that of the Earth?

Earth and Venus have a very similar gravity, but the mass of atmosphere on Venus is much greater (according to this wikipedia article 93 times larger). I know that the chemical composition and ...
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Wasn't Earth a magma ocean before core-mantle differentiation?

I've always thought that the process of planetary accretion was energetic enough to keep the proto-Earth entirely molten, and the subsequent evolution of the planet (the formation of the crust, etc...)...
Swike's user avatar
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7 votes
1 answer
649 views

Diamond at the core of Jupiter

Arthur C. Clarke, who correctly guessed there would be liquid water on Europa, posited a diamond core for Jupiter. Is this possible?
wogsland's user avatar
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3 answers
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In an Earth-like planet with no history of carbon-based life forms, would there be limestone?

The extent of my understanding of limestone is about what Wikipedia says at the very top of the page: Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such ...
TylerH's user avatar
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1 answer
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Can a cryovolcanic eruption be as powerful as a normal volcanic eruption?

The most powerful volcanic eruption in recorded history was the 1815 eruption of Mount Tambora, an explosion equivalent to 33 billion tons of TNT. Is there any way a cryovolcanic eruption could be as ...
StarlightDown's user avatar
7 votes
1 answer
153 views

Was Earth completely covered in Oceans prior to the onset of plate tectonics?

Following recent develoments in geophysics (Schmidt et al. (2014), and a popular summary), we now know there to be a significant reservoir of water in the mantle-transition of planet Earth, now often ...
AtmosphericPrisonEscape's user avatar
6 votes
1 answer
296 views

Why does helium-3 stay in the moon and not escape from it?

So the moon is full of helium-3. Since it's a gas in the moon's vacuum... Why doesn't it escape?
InquilineKea's user avatar
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What time and date is the sun directly overhead a given place on Earth?

In different regions, the sun is directly overhead at different times of the year. When do these event happen?
user avatar
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2 answers
2k views

Is there a time difference between two points at the same longitude but at different latitudes?

Assume we have two cities A and B both at the same longitude (say $45^{0}$ E) but at different latitudes say $8^{0}$N and $90^{0}$ N. Can we get a time difference between these two cities. I raised ...
Gemechu Fanta Garuma's user avatar
6 votes
1 answer
688 views

Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?

This answer to What is the nature of "rock vapor" in this description of the formation of the Moon? explains what "rock vapor" is and how scientists use the concept to understand ...
uhoh's user avatar
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6 votes
1 answer
476 views

What would a planet's sky look like with different chemical compositions, such as low nitrogen, high methane etc?

What are the processes, chemicals and particles involved in creating colour in a planet's sky? Could you give some examples of sky colour processes different from what happens on Earth?
Alexninja1's user avatar
6 votes
1 answer
107 views

Why is the Lunar crust anorthite?

The primordial Lunar crust is mostly calcic plagioclase. However, why did the Lunar Magma Ocean produce so much anorthite, why not a feldspar of a different composition, like albite or orthoclase for ...
Andy's user avatar
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6 votes
2 answers
212 views

Time standard for IERS Bulletin A

IERS Bulletin A and Bulletin B contains Earth orientation parameters. These include the time difference between UT1 and UTC and pole position. The values for these parameters are listed once per day, ...
David Hammen's user avatar
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6 votes
3 answers
411 views

What are the conditions for an ionosphere to form?

I already asked this on Astronomy SE but did not receive any answer so far: What are the prerequisites for an ionosphere to form? For example, can a planet without any atmosphere have an ionosphere? ...
Hackworth's user avatar
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6 votes
1 answer
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Differences between hydrothermal vents on Earth and Europa

Hydrothermal vents are common in areas subject to volcanic activity at the bottom of Earth's oceans. Meanwhile, hydrothermal vents are believed to exist on Jupiter's moon Europa and maybe in other ...
arkaia's user avatar
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6 votes
1 answer
288 views

Calculating Love numbers (tidal deformation) for non-homogeneous planets

I have a question about planetology. I'm not sure if it belongs here, but the astronomy stack exchange seemed a bit odd, too. I would like to enhance my understanding of Love numbers. Love numbers ...
theWrongAlice's user avatar
6 votes
1 answer
101 views

Mars maar craters explosive style formation gravitational effect

"Maars usually form when magma rises within a fissure and interacts with groundwater. If groundwater ceases to interact with magma at times during the eruption, continued magma ascent to the surface ...
Lucian09474's user avatar
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5 votes
6 answers
4k views

Would life on Earth survive without the Sun?

Would life on Earth survive if Sun wasn't there? My teacher told me that there are chances that it would but there would be a lack of gases and chemicals and photosynthesis that occurs with light at ...
Dreamjar's user avatar
  • 159
5 votes
2 answers
225 views

How would a world entirely covered in oceans get the nutrients to support life?

On earth nutrients flow from the land to the ocean. Life on oceans need those nutrients to trive. I was trying to think how an ocean world might support life if there was no land to provide the ...
Todd Hoff's user avatar
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5 votes
2 answers
763 views

What effect does climate change have on the Earth's rotation?

I recently read a blog entry from a leap-second expert explaining that in near term (i.e. last 3 years) the Earth has been spinning ever so slightly faster, delaying the need to insert a leap-second (...
Oddthinking's user avatar
5 votes
2 answers
276 views

What is the CI chondrite concentration of REEs/rare metals, in ppm/grams per ton?

I am researching the abundances of rare earth elements and rare metals in meteorite samples, because I want to investigate the notion that asteroids represent abundant stocks of rare resources. The ...
Accelerandoe's user avatar
5 votes
1 answer
188 views

Cooling the Indian subcontinent using Tibetan Plateau

Apologies if this question may not be up to mark for this stack. I initially asked this on the world building stack but with the lack of replies, I thought I might try my luck here. The main premise ...
wfhhdiwwbiv's user avatar
5 votes
1 answer
123 views

doubt about the 'white spaces' in the maps from satellite

I have a doubt about the 'white spaces' in the maps from satellite. For example, for the atlantic areas I have plotted AOD and appear many areas where sistematically do not have any data (white spaces)...
Adilson Vladmir C. Veiga's user avatar
5 votes
1 answer
337 views

What are the relative contributions of planets to the Milankovitch Cycles?

When reading about the Milankovitch cycles here, it says: If the Earth were the only planet orbiting our Sun, the eccentricity of its orbit would not perceptibly vary even over a period of a million ...
f.thorpe's user avatar
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5 votes
0 answers
153 views

How much does the biosphere contribute to Earth's entropy production?

Papers like 1, 2, etc. and the work of Axel Kleidon (e.g. 3) suggest that the the biosphere increases the production of entropy of Earth but I'd like to know if we could quantify this in a simple way. ...
Anthony's user avatar
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5 votes
0 answers
99 views

How could the solar wind cause strange magnetic pulses on Mars at midnight?

24-Feb-2020 NASA News item A Year of Surprising Science From NASA's InSight Mars Mission says: A new understanding of Mars is beginning to emerge, thanks to the first year of NASA's InSight lander ...
uhoh's user avatar
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5 votes
0 answers
80 views

Mars' strange magnetic pulses at midnight; besides the solar wind what are other possible causes?

24-Feb-2020 NASA News item A Year of Surprising Science From NASA's InSight Mars Mission says: A new understanding of Mars is beginning to emerge, thanks to the first year of NASA's InSight lander ...
uhoh's user avatar
  • 7,122
5 votes
0 answers
166 views

Did Theia collide directly with proto-Earth?

I was learning about the formation of Earth on Kahn Academy where it was mentioned that a protoplanet named Theia had a glancing impact with the earth and formed the moon. It seems like there is also ...
Rhizoqueer's user avatar
4 votes
1 answer
302 views

How do you stop the Australian wildfires?

The Australian fires are the biggest anyone has ever seen and is increasing at a rapid rate causing smog all around the country, approximately 1 billion animals have lost their lives, as of 9 January ...
Yash131997's user avatar
4 votes
2 answers
557 views

What would happen if you hypothetically happened to touch an aurora

I think that if you touch an aurora it will give you radiation damage? But then the solar winds at -90C would freeze you, so speaking metaphorically what would happen?
Artamias's user avatar
4 votes
3 answers
841 views

What natural phenomena increase stratospheric ozone?

Most of us know that the ozone layer gets depleted due to green house gasses and other factors. Which made me wonder, is there any natural phenomenon that causes an increase in ozone?
John's user avatar
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4 votes
2 answers
120 views

Which markers could suggest that there was extinct or extant life on Mars?

Researchers who are involved in study of life on Mars are saying that there might be multicellular life present on Mars, today or in the past. Which traces, markers or environments on Mars could ...
saurabh shukla's user avatar
4 votes
1 answer
973 views

How can scientists measure chemical composition on other planets?

How can scientists measure chemical composition (oxygen, nitrogen etc) and temperature on other planets without being there?
Roberto Estrada's user avatar
4 votes
1 answer
108 views

Why was quartz not a major product of the Lunar Magma Ocean?

Fractional crystallisation generally makes magma more silicic. Why was a substantial quartz layer not a product of the stratification of the Lunar mantle?
Andykins 's user avatar
4 votes
1 answer
1k views

What is the difference between a depleted mantle, and a fertile or enriched mantle?

In a paper about the interior of the Moon, it references depleted mantle sources and enriched mantle sources. Sometimes the latter is referred to as 'fertile'. What is difference between the first two?...
Andy's user avatar
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4 votes
1 answer
503 views

Source of sub-surface ringwoodite water

I was reading about the discovery of vast amounts of water locked up in ringwoodite (see here). The authors of the study seem to suggest that previous ideas, involving water deposits being delivered ...
christopherlovell's user avatar
4 votes
1 answer
62 views

How to estimate altitude of tropopause of other planets?

Is it possible to come up with a formula to estimate the height of the tropopause and the upper layer lapse rate only based on atmospheric composition and other atmospheric parameters (not relying on ...
Redirectk's user avatar
  • 272
4 votes
1 answer
1k views

Geo-Spherical shape of Earth

I know that the best possible approximation of the shape of earth is an oblate sphere. But people also call it as geo-spherical shape of the Earth. What is the meaning of geospherical shape? Does this ...
Talha khan's user avatar
4 votes
1 answer
101 views

Are oceans a major factor in creating high winds on a planet?

This question only pertains to oceans of water and how much they account for the process of creating high winds on a planet with any type of atmosphere.
user5434678's user avatar
4 votes
1 answer
646 views

When will the Earth lose its magnetic field?

Mars lost its magnetic field 4.5 billion years ago according to this article: Mars lost its global magnetic field during the time of this heightened activity. After 500 million years, the Martian ...
user avatar
4 votes
1 answer
312 views

where are the poles of rotation of the tectonic plates located?

Euler's "fixed point" theorem ... can be stated as: The most general displacement of a rigid body over the surface of a sphere can be regarded as a rotation about a suitable axis which passes ...
Harthag's user avatar
  • 143
4 votes
0 answers
49 views

How long for tectonic plates to develop from a planetary, molten planetary surface?

On Earth or an Earth-like planet, how long does it take for a molten surface to solidify into planetary crust, and how long does it take for that crust to develop into tectonic plates?
Wax's user avatar
  • 141
4 votes
0 answers
376 views

Puzzle using relative dating principles

This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here. Here is what was told: -"Worms" (curved ...
throwaway0555585's user avatar