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Questions tagged [planetary-atmosphere]

Atmospheres of planets, moons, and other solar system bodies excluding stars. For those, use "stellar-atmosphere" instead. For influences of Earth's atmosphere on astronomical observations use "atmospheric-effects". For other questions about the Earth's atmosphere, Earth Science SE is probably the right site. https://earthscience.stackexchange.com/

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What would happen to the sky colour if SO2 made up 95% of the atmosphere?

Taking into account the Rayleigh scattering phenomenon, assuming that the atmosphere is 1 bar, how would the light from the G2V-type star interact with this kind of environment? Could the colour of ...
Sam Biswas's user avatar
7 votes
1 answer
1k views

Is Earth's Atmospheric Thickness Related to Cosmic Ray Radiation?

Why does cosmic radiation diminish entirely, reaching zero, at sea level? If the atmosphere's thickness were random, it should not happen at sea level, but at a random altitude. Is there a specific ...
wepajakeg's user avatar
1 vote
1 answer
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Meteor visibility from two locations

If I observe a meteor entering the atmosphere at the zenith from my location. How far does a second observer have to be from my position to see the meteor 10 degrees above the horizon. Or what is the ...
Robert's user avatar
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2 votes
1 answer
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Carbon dioxide on terrestrial planets

I guess it's a basic question, but why do Venus and Mars have so much carbon dioxide in their atmospheres? The vast majority of the universe is hydrogen (and a small percentage is helium). Why did the ...
Goose's user avatar
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2 votes
2 answers
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What stops terrestrial planets from becoming watery gas giants with water vapour atmospheres?

How come planets beyond the frost line form with ice cores but terrestrial planets didn't accrete anywhere near as much water vapour? The way I understand accretion to work, planets form out of ...
Ale Kid's user avatar
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2 votes
1 answer
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Which of the blocked radiation windows will (mostly) open if one where to observe from the surface of Mars, instead of the Earth?

Earth’s atmosphere is composed of about 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases. Trace amounts of carbon dioxide, methane, water vapor, and neon are some ...
some_math_guy's user avatar
5 votes
1 answer
440 views

What will it take to start measuring the rotation rate and direction of exoplanets? Which instrument(s) current or future are most likely to do it?

@ProfRob's answer to Is it coincidence that the earth's rotation and revolution are in the same direction? explains several important aspects of models for planetary formation, angular momentum and ...
uhoh's user avatar
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Would it be possible to see dust devils on Triton?

Triton has an extremely thin atmosphere, but thick enough for haze and winds. Plumes on Triton eject gas, which carries with it micrometer sized solid particles, which leave streaks on the surface ...
M. A. Golding's user avatar
2 votes
0 answers
90 views

Atmosphere colour from orbit

I know a few different resources for determining the colour of a world's sky depending on its star and atmospheric pressure, but I haven't been able to find anything for how it would look from space (...
Kazon's user avatar
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15 votes
2 answers
3k views

Why is it impossible to infer the surface temperature of Venus by spectroscopy observation from earth?

It is well known that the surface temperature of the sun is determined by fitting the sunlight with the black-body spectrum. Why is this inappropriate for Venus? I have the question because of the ...
S. Kohn's user avatar
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7 votes
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Is there a formula for calculating surface temperature of a rocky world based on atmosphere and solar input?

For example, a thicker atmosphere would probably lead to less temperature variation . . . I assume that much is obvious. And, greenhouse gases trap heat. But when posed with a question like "...
userLTK's user avatar
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Is the level of carbon monoxide on Mars at an expected equilibrium level?

Is the level of carbon monoxide in the atmosphere of Mars (0.0747%) exactly what would be expected under equilibrium conditions given the ambient Martian atmospheric temperature, pressure and ...
Slarty's user avatar
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4 votes
2 answers
722 views

Why are heavier hydrocarbons not present in lower part of Uranian atmosphere?

I recently answered this question. While researching for the answer, I found one point quite counter-intuitive. The heavier hydrocarbons resides in stratosphere while methane, the lightest hydrocarbon ...
Nilay Ghosh's user avatar
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3 votes
1 answer
225 views

When did Venus get as hot as it is now?

My previous question turned out to not ask the question I thought I was asking. I have read that Venus began its heating-up around 700-750 million years ago. When did the Venusian atmosphere get ...
Michael Bonnet's user avatar
4 votes
1 answer
109 views

When did Venus reach approximate radiation equilibrium?

I have read that Venus is roughly at radiation equilibrium - that is, heat out is approximately equal to heat in. I have also read that Venus began its heating-up around 700-750 million years ago. My ...
Michael Bonnet's user avatar
23 votes
5 answers
8k views

Why is Uranus called a "green planet"?

Uranus is called a green planet, although it appears blue in many of the photographs including those taken by spacecraft, like Voyager 2, Hubble, and JWST. NASA's Uranus page mentions it to be bluish-...
Dhruv Nayak's user avatar
1 vote
0 answers
205 views

How common are there planets with significant share of oxygen in atmosphere?

Has been there detected any exoplanets with significant share of oxygen in atmosphere? What does the theory predict? Superficially this looks like it should be fairly common: there is a lot of water ...
Anixx's user avatar
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2 votes
2 answers
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Trying to identify what I saw in the sky

This occurred at around 12:45 AM on Saturday August 12th somewhere in the center of Nantucket Island Massachusetts. We were trying to spot the Perseids meteor shower when I noticed a strange green ...
Bobby Saville's user avatar
4 votes
2 answers
109 views

Does rotation on their axis cause winds in gaseous planets?

As far as I know, as planets rotate around their axis, they can influence winds but not cause them (like the Coriolis effect) However, does this apply only for rocky planets? Do rotation alone in ...
vengaq's user avatar
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4 votes
2 answers
246 views

Acetylene at Uranus? What's JWST's evidence and current thinking of how it's possible?

After about 03:22 in PBS Newshour's July 13, 2023 James Webb Space Telescope prompts scientists to rethink understanding of the universe JWST Interdisciplinary Scientist Heidi Hammel talks about ...
uhoh's user avatar
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6 votes
2 answers
90 views

Meteors arriving to a planet's atmosphere?

Imagine a planet with little or no wind activity or precipitation, but that still has an atmosphere. When a meteoroid reaches the atmosphere and burns, it converts into dust and gas. Does this gas and ...
vengaq's user avatar
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2 votes
0 answers
34 views

Could rogue planets with cold nucleus have winds or water currents/waves due to the planet's rotation?

Are there any types of wind or waves caused and produced only and exclusively by a planet's rotation? Not influenced by the planet's rotation, but produced solely by it? In the case of waves, are ...
vengaq's user avatar
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1 vote
2 answers
70 views

What is the concentration of molecular oxygen in the Martian atmosphere?

In the early 1970's and prior to the Viking landers, T. Owen measured the oxygen in the Martian atmosphere at 0.3%, I believe by doppler shift methodology through the Earth's atmosphere (wow). During ...
Incredible II's user avatar
3 votes
1 answer
161 views

Do red dwarf stars get dimmer over time, the opposite of most other main sequence stars?

It is common knowledge, for instance, that the sun has increased in brightness by roughly 40% since its formation... (The apparently early appearance of life has led to the 'Faint young Sun paradox', ...
Kurt Hikes's user avatar
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21 votes
2 answers
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Why is Venus's atmospheric pressure 75 times that of earth when carbon dioxide is only 1.5 times heavier than air?

Obviously I have forgotten by basic college chemistry. I am getting carbon dioxide at 1.87kg per cubic meter and compared it to nitrogen and oxygen but source says carbon dioxide is 1.5 times heavier ...
Sedumjoy's user avatar
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3 votes
2 answers
215 views

Venus Atmosphere Color

I want to ask what color is the Venusian atmosphere without the presence of dense clouds for our human vision? I searched for this question, and did not find a suitable answer. Everywhere they write ...
Mikee's user avatar
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4 votes
2 answers
537 views

Can a tidally locked planet sustain a magnetic field

The vast majority of stars in the Galaxy, and probably the universe, are red dwarfs. The habitable zones of these stars are very close to the stars themselves, often within what would be Mercury’s ...
user98816's user avatar
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1 vote
0 answers
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How to calculate greenhouse effect on a planet (newbie)

I built a calculator to calculate a planet's atmospheric pressure at an altitude with the formula below. How does greenhouse effect relate to the formula above? How to calculate it? I compared the ...
bridgeofdata's user avatar
0 votes
0 answers
163 views

How common are exoplanets with no atmosphere?

I'm guessing that real data about exoplanets will be unhelpful because it's hard to detect low-mass planets, and thus answers are likely to be based on the kind of educated-guesswork that we relied on ...
Tom's user avatar
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3 votes
1 answer
78 views

Do conjunctions of planets block out the sun and cause measurable cooling of the atmosphere on one of the planets?

Is a significant amount of light energy blocked by one planet such that there is noticeable cooling of the atmosphere of another?
user avatar
2 votes
0 answers
80 views

Are stagnant-lid Earth analogues guaranteed to become Venus-like?

In our current understanding of Venus, two things are generally accepted: Venus reached its thermal tipping point at least 700 Ma. As the Sun's luminosity gradually increased with age, its average ...
Thoth's user avatar
  • 181
2 votes
1 answer
73 views

How close does a double-planet have to be to provide magnetic protection to a smaller body?

A spinoff of my previous question, regarding the Orbital Stability of a Double Planet System. Imagine two closely-orbiting bodies with a semi-major axis of 79,250 km. One of which is 2M🜨, with a ...
Thoth's user avatar
  • 181
1 vote
1 answer
116 views

Is it possible for us to have mistaken a few brown dwarfs and a few white dwarfs for a burning ethane-octane-oxygen planet?

Is it possible that we humans may have missclassified a handful few but not all brown dwarf stars or white dwarfs, when there really could be possibly a burning planet? Assuming a large enough planet ...
Dimitri Morvaine's user avatar
2 votes
0 answers
77 views

If Ganymede had a thick, Earth-like atmosphere, would the surface be protected from Jupiter's intense radiation?

Obviously, this is a totally hypothetical, alternate version of Ganymede, since it would also need to have more mass and a stronger intrinsic magnetic field to hold onto a substantial atmosphere. But ...
Elhammo's user avatar
  • 1,107
2 votes
1 answer
113 views

How might a lower gravity planet sustain a warm, earth-like atmosphere?

I'm designing a hypothetical lower-gravity planet with 0.47M, 0.79r and 0.76g, with a similar density to Earth. I've already determined that this mass, radius, and density will allow my planet to ...
Elhammo's user avatar
  • 1,107
5 votes
0 answers
288 views

Why aren't there sulfuric acid seas on Venus?

It's commonly known that sulfuric acid rain doesn't reach Venus' surface. It evaporates instead because the surface it too hot. But considering how high the pressure at the surface (9.3 MPa), shouldn'...
Prido1024's user avatar
5 votes
0 answers
36 views

How to model the kinematics of gases expelled from comets and planetary atmospheres?

Once the ices of comets sublimate, where do they move to, and with which equations do you describe their motion in the interplanetary medium? Similarly, where do the gases that are stripped from the ...
Astrolien's user avatar
  • 151
4 votes
2 answers
2k views

What are the scale heights of the atmospheres of the Solar System worlds?

What causes the relative scale heights of the atmospheres in the Solar System? In various scientific contexts, a scale height, usually denoted by the capital letter H, is a distance over which a ...
M. A. Golding's user avatar
1 vote
2 answers
194 views

Is the gas in a planet forming disk around a star comparable in density to an atmosphere?

If you were standing on a planetesimal in the planet forming disk of a new solar system (or our own, billions of years ago), would you be able to feel "interplanetary wind"? Would it be ...
Dennis's user avatar
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6 votes
1 answer
284 views

What value of density would a planet need to be classified as a mini-Neptune?

EDIT: well, now I have more For reference: A terrestrial planet is a planet that is made out of silicates and metals. A Mini-Neptune is, as far as I know, the smallest type of giant planet (arguably,...
KEY_ABRADE's user avatar
27 votes
5 answers
6k views

Can a planet with no atmosphere be orbited at extremely low altitudes?

Can a planet that has absolutely no atmosphere be orbited by a spacecraft at extremely low "altitudes" (if you'd even call it altitude at such a low orbit. For instance, if this planet's ...
veezy_101's user avatar
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4 votes
0 answers
68 views

Titan's Atmosphere

Is Titan's atmosphere being continually regenerated? What is the current thinking on the origins and maintenance of Titan's atmosphere after the landing of the Huygens probe. As I remember, ...
Incredible II's user avatar
8 votes
1 answer
165 views

Would lightning on planets with noble gas rich atmospheres cause a glow similar to an electric discharge lamp?

I've read about how noble gases in gas tubes emit varying colors of light when electricity is passed through them For a planet with noble gas rich atmospheres (say >20%), would a lightning strike ...
Hash's user avatar
  • 503
3 votes
3 answers
518 views

Are planets far from their parent star more likely or less likely to have an atmosphere?

Are non-gaseous planets (e.g. super-Earths) that are either rogue or very far from their parent star(s) less likely or more likely to have a significant atmosphere? On one hand planets closer to their ...
Giovanni-Reinstate Ceres Pluto's user avatar
-2 votes
2 answers
290 views

If the sky is the limit...where does the sky start? [closed]

Does the "sky" start anywhere that the land is not touching? Does it start after the troposphere? After the atmosphere?
ehelmick93's user avatar
2 votes
0 answers
160 views

Up to what distance from the Moon does the Moon's gravity hold its exosphere before it is being cast away by solar wind?

Up to how far from the Moon is the Moon's exosphere gravitationally bound to it? For the Earth's exosphere it is 120,000 mi (190,000 km) or half the Moon's distance from the Earth, beyond that the ...
LoveForChrist's user avatar
2 votes
0 answers
48 views

When will Jezero crater on Mars reach its lowest atmospheric pressure and what pressure will that be?

In the first sols of the Mars 2020 mission the local pressure was something above 750 Pa. It has been decaying since then and is now less than 650 Pa, this is what required Ingenuity's rotorblades to ...
LoveForChrist's user avatar
1 vote
1 answer
111 views

How would the surface of Mars compare with the Atacama desert for millimeter wave (and shorter) radio astronomy?

In this answer to What kind of experiments would a scientist do on Mars? I suggest that the resemblance of the ALMA array's site in the Atacama Desert to the surface of Mars suggests millimeter ...
uhoh's user avatar
  • 30.7k
3 votes
2 answers
151 views

Which Venus scientists discovered the hole in the ozone layer?

After 21:00 in Venus: Earth’s Evil Twin or Just Misunderstood? (live public talk) from the JPL YouTube channel the person being interviewed "Sue Smrekar, Rocky ...
usernumber's user avatar
  • 17.6k
6 votes
1 answer
168 views

How does the Hubble Space Telescope measure the speed of the wind inside Jupiter's Great Red Spot?

Space.com's Jupiter's winds of change show increased storm speeds in Great Red Spot and Hubblesite.org's Hubble Shows Winds in Jupiter's Great Red Spot are Speeding Up both link to the recent open ...
uhoh's user avatar
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