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Starting a fire in a cold planet that was full of flammable gas

The outer parts of Neptune are mostly hydrogen and helium. There are small amounts of other gases such as methane, ammonia and water vapour. However, there is no oxygen at all. If you took some of ...
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What is the difference between gas and dust in astronomy?

Yes, metals and other elements and molecules can exist in gaseous form under the right conditions of temperature and pressure. A "gas" is simply one of the fundamental states of matter, as in solid, ...
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What will happen when landing on Jupiter?

Jupiter does not have a "surface" and nor is there anything but an arbitrary division between interplanetary space and where its atmosphere begins. The crushing pressure is its atmospheric pressure. ...
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Gas halo of our Milky Way Galaxy

The scale height of gas in a disk (if it were in equilibrium) is roughly $kT/mg$, where $T$ is the temperature, $g$ is the gravitational field, $m$ the mean mass of agas particle, and $k$ the ...
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Why argon instead of another noble gas?

why Argon specifically? Both helium and neon are pretty lightweight, tend to vaporize easily even at low temperatures, and are chemically inert. For all these reasons combined, they tend to not get ...
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What is the difference between gas and dust in astronomy?

In astronomy, there is no formal definition of the threshold between gas and dust. Gas can be monoatomic, diatomic, or molecular (or made of photons, in principle). Molecules can be very large, and in ...
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What would the pressure and temperature of gas be, right above Jupiter's gas/liquid boundary?

Technically there isn't really a gas-liquid boundary because temperatures are well above the critical point of hydrogen (33K and about 18bar). It's a supercritical fluid. There are important changes ...
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How do astronomers detect gases that are in the atmosphere of exoplanets?

It is only possible to detect gases in transiting Exoplanets. The spectrum of the star is taken when the Exoplanet is not in transit and again when in transit. The differences between the spectrums is ...
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Are gas giants supported by thermal pressure?

I am not sure what you mean by "thermal" pressure. Jupiter is supported by pressure, just like all objects that are in (approximate) hydrostatic equilibrium. That pressure is provided by your ...
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Why is the "green" comet C/2014 Q2 (Lovejoy) red in this picture?

Mainzer et al. 2014 characterize the performance of the reactivated NEOWISE. Having run out of cryogenic coolant for the original WISE's 12 and 22 μm bands, it only detects in the 3.4 and 4.6 μm ...
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What is the diffuse ionized gas?

The "diffuse ionized gas" (DIG) is another term for the phase of the interstellar medium (ISM) usually called the warm ionized medium (WIM). With a temperature of the order $10^4\,\mathrm{K}$, but ...
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Why is it safe to assume that K = 3/2kT in a self-gravitating gas

I will use some concepts form statistical mechanics, I hope you are familiar with some of the concepts. Consider a gas of $N$ particles of mass $m$ with Hamiltonian function H(\bar{q}, \bar{p}) = \...
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How does gas in accretion disks of supermassive black holes create orbital torques on smaller black holes within the disks causing them to migrate?

Not really my area, but this question is probably related to the planetary migration in circumstellar disks. In this case, the migration is caused by gravitational interactions between the planet and ...
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What are the so called clouds of dust and gas made of?

The clouds of gas and dust that form stars are usually what are called Molecular Clouds and Giant Molecular Clouds (GMCs). The "Molecular" means that most of the atoms are combined into molecules ...
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