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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Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Accurate?

I'm an artist (and science enthusiast) and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors (as perceived by human vision) for exoplanets that ...
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Why is Saturn invisible in this radar image of its rings?

The image below is from Radar imaging of Saturn’s rings Nicholson, P. D. et al., Icarus 177 (2005) 32–62, doi:10.1016/j.icarus.2005.03.023 and discussed further in this answer to How did Arecibo ...
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Refraction by Saturn's atmosphere - how dense is it here?

This tweet from CassiniSaturn shows an image of Saturn's rings being optically distorted by the dense atmosphere. It is explained more fully on this page and is available here. The refraction is ...
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Why has Venus's atmosphere not been stripped away by solar wind?

This answer on Space Exploration to a question about Mars says that one reason Mars has such a thin atmosphere is because it lacks a magnetic field to protect it from the effect of double solar winds. ...
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Why is twilight longer in summer than winter and shortest at the equinox

I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with ...
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At what depth on Mars would the atmosphere have equal pressure of that on Earth?

I know the atmospheric pressure on Mars is less than that of Earth, and so is its gravity. However, I know that the deeper you go (e.g. in a cave or a hole that is dug), the more atmospheric pressure ...
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Why do stars twinkle but planets don't [duplicate]

Many people say that stars twinkle because of Earth's atmosphere. However, the atmosphere is still there when we look at planets and don't see they twinkling. Is there a clear scientific consensual ...
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How thick or deep does solid carbon dioxide accumulate on Mars?

On Mars is there an area in which all the $CO_2$ evaporates exposing dirt near the pole? How deep can solid $CO_2$ accumulate during winter in that area during the Martian Winter? https://space....
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Why did Venus not lose its atmosphere without a magnetic field?

It is often stated that the magnetosphere not only shields the planet from cosmic radiation, but also prevents atmospheric loss. Why then did Venus not lose most of its atmosphere if it doesn't have a ...
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Gravitational pull needed to keep a gas in atmosphere

How can you determine the gravitational force needed to keep a particular gas in the atmosphere of a planet (for example, carbon dioxide (CO2))? I came across the following formula $\left(\frac{8RT}{...
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What would the pressure and temperature of gas be, right above Jupiter's gas/liquid boundary?

Older pages like this "Exploration of the Solar System" course page describe the transition as being a few hundred kilometers down. More recent findings seem to put the boundary deeper. See The ...
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...but where did Mars' atmosphere actually GO?

In this answer to How is space a vacuum when there are planets, gases, etc? I mention that most of Mars' original atmosphere was swept away by the solar wind after the planet lost its magnetic field ...
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How are the compositional components of exoplanet atmospheres differentiated?

How are exoplanetary atmosphere compositional spectra distinguished from those of the parent star(s), from the composition of the planetary surface or any other factor? Is it actually possible to ...
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Loss of atmosphere on Mars

If the atmosphere on Mars was once much thicker, how was it likely lost? Was it due to interaction with the solar wind, the small size of the planet, both, or something else, and approximately how ...
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What was the first astronomical measurement which demonstrated that "the Earth is surrounded by vacuum"?

The question Who was the first to realize that the Earth is surrounded by vacuum? was closed because some users felt it was answered by answers to a different question in an different SE site: Who was ...
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How does Titan maintain its atmosphere?

Titan, which is smaller than Mars, has an atmosphere but Mars is not able to maintain its atmosphere. Even Luna (the Moon) doesn't have an atmosphere. Why is Titan able to hold an atmosphere, despite ...
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Why do gas giants have clearly delineated surfaces, whereas the Earth's atmosphere fades into space?

I've just seen this Forbes article. Why do gas giants appear to have clearly delineated surfaces, whereas the Earth's atmosphere fades into space? Is it just a matter of scale? Or is there some ...
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Is the wind's intensity on Mars similar to Earth?

I've read that in Mars' poles, the winds can be as fast as 400 km/h, when the poles are exposed to sunlight because the frozen $CO_2$ sublimes. I know that the Martian atmosphere is much thinner than ...
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How would astronomical seeing on Mars differ from that on Earth?

Astronomical seeing is the limiting factor for the resolution of all but the smallest Earthbound telescopes. Source Stunning advances in adaptive optics (along with it's predecessor speckle ...
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How does Io's atmosphere behave locally near volcanic plumes?

Io's surface air pressure is about $0.3 {\rm mPa}$ but Io's atmosphere is strongly variable, depending on whether it's on the near side or far side of Io (relative to Jupiter) and it collapses at ...
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How can you determine the initial volume of a planet's atmosphere?

Since the surface pressure of a planet is determined by the mass of the column of gasses above it one would surmise that to determine the pressure you must know the volume and mass of the atmosphere. ...
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Extraterrestrial snow?

What do we know about extraterrestrial snow? On which (exo)planets or (exo)moons do we have direct hints for its existance? This is indeed a children's question, but I struggle to answer it ...
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Does lightning on Venus affect the chemical composition of the clouds?

It is established that lightning occurs on Venus due to the presence of sulfuric acid clouds. Does this constant electric discharges and possible electrolysis affects the composition of the clouds on ...
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Have auroras on Titan been observed yet?

After reading the very insightful introduction to auroras on other planets I started digging and found various questions and some answers here on the same topic, see below. What I did not figure out ...
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Can you assume atmosphere height for the purpose of surface pressure calculation?

Given that by definition of scale height an atmosphere thins by a factor of 1/e^x where x is elevation in terms of scale height multiples (See the table here: Definition of Scale Height), can we ...
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Characteristics of Venus' jet streams?

Since the Voyager missions, the atmosphere of Jupiter received great attention, its jet streams made it into text books on geofluid mechanics, including their characteristics like the how they meander,...
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Does the Moon have any oxygen in its atmosphere?

Since the moon has gravity, it's almost impossible that there aren't some gasses trapped on the surface by the moon's gravity. Has any free-floating oxygen been found on the Moon? If so, in what ...
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Do brown dwarfs have stripes?

Brown dwarfs (BD) are often depicted with stripes. brown dwarf Jupiter Pictures of BD resemble Jupiter but brown dwarfs ...
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What is the current accepted theory as to why Titan has retained its atmosphere?

Titan (moon of Saturn) is unique in that it possesses a very thick atmosphere. However, Titan is certainly is not the largest of the moons - Ganymede being larger. What is the current accepted ...
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9 votes
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Mars vs Venus: the retention of atmospheres in relationship to Earth

Correct me if I'm wrong, but the factors than enable a planet to retain or lose an atmosphere seem to be: 1. Magnetic Field, 2. Solar Winds, 3.Weight of Gases, 4. Planetary Temperatures. 5. Distance ...
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6 votes
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What is the underwater temperature of Europa?

If Europa has an oxygen atmosphere with a water mantle, is it possible that there could be life under the crust of Europa ice on the ocean where it is warmer? What could be the temperature under the ...
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How are sulfuric acid clouds able to completely cover Venus?

It is a well-known fact that an opaque layer of highly reflective clouds of sulfuric acid completely shrouds Venus preventing its surface from being seen from space in visible light. This is mentioned ...
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What is the nature of bright spots found on Uranus?

The following text is from space.com which was written during the time of discovery of the first dark spot on Uranus: During the past decade, many bright spots have been seen on Uranus in both red ...
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What is the underlying nature of the dark spot found on Uranus?

What is the nature of bright spots found on Uranus? actually quotes Space.com's Uranus Has a Dark Spot which says: During the past decade, many bright spots have been seen on Uranus in both red and ...
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4 votes
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Where does the CO2 in Mars atmosphere come from?

As far as I know, Earth and Mars were relatively similar when the solar system formed. So most of the CO2 was used to form carbonic rocks (right?). I found that tectonic movements are the reason that ...
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Are there many faint meteors that are too faint to see with the naked eye?

I remember one time a while back looking at the night sky through night vision goggles. One interesting thing I noticed is that there appeared to be many very faint meteors in the sky practically all ...
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What other hints of possible life in Venusian atmosphere have we dismissed?

Now that phosphine has probably been discovered in relatively large quantities in the Venusian atmosphere, I heard that there have been other unexplained phenomena (i.e. dark patches) seen. Does ...
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3 votes
1 answer
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How do astronomers detect gases that are in the atmosphere of exoplanets? [duplicate]

Exoplanets are planets that are located outside our solar system - whether that be orbiting a star or drifting past one. Now, the closest star to us is Alpha Centauri which is just over four light-...
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When examining an exoplanet's atmosphere is the star's emission spectra or planet's light used?

My understanding of the main method we use to figure out an exoplanet atmosphere composition is that when a exoplanet transits their sun, visible light passes through the planet's atmosphere, and ...
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Were K2-141b and WASP-63b selected as the first two exoplanet atmospheres for JWST to look at during its first year of observations? If so, why?

In The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part: The new telescope will augment science performed by Hubble, not ...
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Why are cirrus clouds more common on Mars?

Mars water ice clouds are often associated with regional- to-global circulation and saturation conditions, as opposed to local convective overturning, and so typically exhibit cirrus rather than ...
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If a rocky world is large enough (not a gas or ice giant) can it have helium from the primordial disk in its atmosphere?

When planets are formed do only gas and ice giants accrete hydrogen and helium? Does this accretion have to be beyond the "snow line"? In other words, would all hydrogen or helium in the atmosphere ...
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1 vote
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The consequences and the mechanisms of a shift of the Earth away from the sun

First premise: I have already made this question in the worldbuilding section, but since it is a very specific question many have recommended me to write in the astronomy section so here we are. ...
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