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 hasn't all the water on earth evaporated and been frozen at the poles?

It seems like over a long enough time scale, if the surface temperature of a planet varies between perennially below freezing and occasionally above freezing, that all of the water on the planet would ...
Cirdec's user avatar
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Wind patterns on a tidally locked planet (one side always faces the sun)

I'm moving this question from Worldbuilding StackExchange (Link). I know it's not strictly about Earth, but I'm hoping it will still be accepted here since it's related to meteorology. Here we go: My ...
Alon's user avatar
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3 votes
1 answer
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Pre-Phanerozoic CO2 levels and pluricell life influence in C Earth's cycle

This graph presents an estimate of Phanerozoic CO2 levels on Earth. From the onset of the graph, it appears that CO2 levels are rising. However, I've come across papers, such as this one, suggesting ...
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2 votes
1 answer
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Can a tectonic plate subduct under one plate while another plate subducts under it along the same boundary?

At a triple junction plate boundary there are three tectonic plates meeting. We have plenty of examples of these boundaries on Earth, notably the Afar Triple Junction, Mendocino Triple Junction, and ...
Martamo's user avatar
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1 answer
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Displacement-Length scaling relationship on extraterrestrial faults

Faults on Earth share a similar displacement/length ratio of around 0.03 which scales from very small faults to very large faults. Would this apply to faults on other planets and if so, are there any ...
Andykins 's user avatar
1 vote
0 answers
144 views

Planetary surface temperature from first principles

How can you calculate planetary surface temperatures from first principles? The obvious application is for Earth, with a surface temperature of $288$K. I want a calculation with no fudge factors (i.e.,...
Sebby's user avatar
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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
58 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
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Can the planetary alignment actually affect earthquakes? [duplicate]

We've been hearing a lot these past few days about planes alignments and how it would affect seismology. How scientifically true is that?
Haya's user avatar
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2 votes
0 answers
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Moist adiabatic lapse rate

I asked this question in the Physics SE but it still lies unanswered. Hopefully Earth Science SE is more knowledgeable in the matter. Wikipedia gives the following equation to calculate the moist ...
Redirectk's user avatar
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8 votes
2 answers
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Is it possible for tsunamis to occur on deep water planets?

Assume a water planet with an ocean depth of about 200-500 km. Would a very strong ground-quake happening at the very bottom of the planet's ocean floor be able to cause a large tsunami to rise up to ...
ZanMoon-chan's user avatar
11 votes
2 answers
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What oxidised the soil on Mars?

What exactly was it in the ancient Martian atmosphere that made it red? Was it water, molecular oxygen or something else?
Andykins 's user avatar
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Why are there no tholins in the inner solar system?

There’s plenty of carbon dioxide and radiation throughout the solar system, why is it a phenomena only associated with the outer planets?
Andykins 's user avatar
2 votes
0 answers
26 views

Calculate original volatile content of a degassed mineral

A lunar apatite sample has a relatively low OH content of 5 ppm, but a an elevated D𝛿 of 11,000‰ (vs. SMOW). Assuming that water had an original figure of around -100‰ or so, how do I estimate the ...
Andy's user avatar
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6 votes
1 answer
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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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1 answer
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What does fugacity mean in the context of geology?

I am reading about water in the Lunar mantle, however it mentions fugacity a lot. What does it mean in this context?
Andy's user avatar
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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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0 answers
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What would the climate and greenhouse effects be if the oceans contained half as much water?

Imagine the Earth contains 50% the water it currently contains. The oceans are still located in the same place, but they are much shallower. How would this affect the climate and the climate stability ...
Elhammo's user avatar
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1 answer
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How might 25% lower gravity affect precipitation on an Earth-like planet? [closed]

I'm working on a science fiction project and hoping someone who knows something about climate can answer this question for me: if Earth had 25% less gravity, how would that affect precipitation? I ...
Elhammo's user avatar
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6 votes
1 answer
687 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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2 votes
1 answer
277 views

What is the elevation angle of sun at lunar poles?

The Moon's orbital plane is inclined by about 5.1° with respect to the ecliptic plane, whereas the Moon's equatorial plane is tilted by only 1.5°.
Ananya Srivastava's user avatar
2 votes
1 answer
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How exactly can one make out the direction of and temperature of winds [closed]

I am trying to make a fictional world, but I want to be as realistic as humanly possible with the winds and climate. So my question is, knowing various parametres, how exactly can I make out what ...
Zoey's user avatar
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5 votes
1 answer
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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
3 votes
1 answer
551 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
7 votes
1 answer
143 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
2 votes
1 answer
178 views

Plain-language summary of why Uranus and Neptune are different than Earth in having large offsets of their dipole field?

This answer to Why is the magnetic axis of Uranus and Neptune off center? in Astronomy SE perplexes me, partly because I can't understand the block quotes and partly because they constrast those ...
uhoh's user avatar
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3 votes
1 answer
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Climate on Venus after it becomes tidally locked

Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO2 from atmosphere to precipitate in liquid form to make an ocean?
Anixx's user avatar
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5 votes
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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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6 votes
1 answer
256 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
5 votes
2 answers
732 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
3 votes
1 answer
176 views

How do subsurface oceans form under a rocky crust?

New data about Ceres has just been released. Raymond et al. (2020) show the existence of gravity anomalies interpreted as low density pockets of brine under the crust. They show how impacts can ...
Jean-Marie Prival's user avatar
3 votes
2 answers
238 views

Now Mars is pulsing 3 times per night in the UV, can anyone explain these waves in simple terms? Do these waves have analogies on Earth?

I link below to questions on another kind of Mars pulse) Phys.org's NASA's Maven observes Martian night sky pulsing in ultraviolet light links to the new paper Imaging of Martian Circulation Patterns ...
uhoh's user avatar
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8 votes
0 answers
196 views

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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1 vote
2 answers
610 views

Why does the Earth's crust have more aluminum than magnesium while the Sun has more magnesium than aluminum?

Magnesium represents 0.07 % of the composition of the Sun's photosphere while aluminum represents 0.006 %. Therefore, there is much more magnesium than aluminum in the Sun's photosphere. But the same ...
URIZEN's user avatar
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4 votes
1 answer
981 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
3 votes
4 answers
382 views

Do we know anything about the nature of Earth's core that hasn't come from magnetic or seismic measurements?

There is much known about Earth's core from painstaking analysis of seismic data, and from detailed magnetic field maps and trends over time. Are there any other measurements that have contributed to ...
uhoh's user avatar
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1 vote
0 answers
102 views

Earth-like conditions on Titan: is it feasible that Titan once had seas and lakes of liquid water?

Given that: 1) Four billion years ago Saturn was hotter and radiated strongly in the infra-red. . . . . . . . . . 2) Like Earth's moon, Titan was then closer to its planet. . . . . . . . . . 3) Like ...
Michael Walsby's user avatar
3 votes
1 answer
127 views

How do they get "deep lunar mantle" samples?

Phys.org's Study suggests Earth and Moon not identical oxygen twins says They found that the oxygen isotopic composition varied depending on the type of rock tested. This may be due to the degree of ...
uhoh's user avatar
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2 votes
1 answer
166 views

Why is Venus so cracked?

Wired.com's Space Photos of the Week: Perfectly Safe Celestial Coronas includes radar images of the surface of Venus taken from spacecraft in orbit around it. One of them shown below. What causes ...
uhoh's user avatar
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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
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5 votes
0 answers
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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
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8 votes
2 answers
716 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 ...
user avatar
4 votes
1 answer
301 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
1 vote
2 answers
331 views

Will Venus eventually overheat? When it happens, what will happen to it exactly?

Venus is a runaway greenhouse planet, so it won't let any of the heat absorbed from the Sun out by radiation, yet it will still take rays of energy from the Sun. So what will happen to Venus? Will it ...
Deha Ortasarı's user avatar
1 vote
2 answers
156 views

Centripetal Force Perfect Ball and Water

I made a question in WolrdBuilding as I was directed to. There a user said that with a perfect ball all water would pool to the equator because of centripetal force. What I do not understand is how ...
George Ntoulos's user avatar
4 votes
2 answers
116 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
1 vote
0 answers
67 views

Similarity of seasons on Neptune and Earth [closed]

We all have basic ideas about planets and their seasons..But my question is that why do NEPTUNE and EARTH have similar seasons although their compositions are completely different..On earth Nitrogen ...
saurabh shukla's user avatar
1 vote
1 answer
309 views

Effects of Centrifugal Force on Gravity Vectors?

I've been asked this question twice now from our favourite science denying community, and I don't know how to parse it. I can do centrifugal force and gravity given mass, but have never tried to even ...
Russ Walker's user avatar
4 votes
1 answer
307 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
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