Questions tagged [gas-giants]

Questions regarding massive planets composed of layers of gases, such as hydrogen and helium, surrounding a solid/liquid core.

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2
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4answers
462 views

Is it possible for a star to orbit a planet?

Is it possible for a red dwarf to orbit a gas giant? OR Has this happened and it is just assumed that the gas giant is orbiting the star?
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4answers
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Is Jupiter made entirely out of gas?

I heard that Jupiter is made out of gas. But in school I learned that Jupiter has gravity which is 2.5 times that of Earth (Gravity that can tear apart a comet) and gravity is proportional to mass. ...
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2answers
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Where do we define the “surface” of a gas planet?

Since gas giant consist of most gas components, where do we establish their "surface"? My take is basically to take the limit in which all light is opaque. For example, in this photo: The ...
5
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2answers
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Why is the core of a gas giant supported by electron degeneracy pressure instead of nuclear fusion?

After a Sun-sized protostar forms, its core will become denser over time due to radiation. The core eventually gets dense and hot enough for hydrogen fusion to take place. In the late phases of the ...
8
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1answer
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How is the diameter of a gas giant calculated?

As we know atmospheres of celestial bodies don't just stop at a given distance. They gradually become less dense as you move away from the center. I understand that the diameter of stars is ...
5
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1answer
464 views

Why are the natural satellites (moons) of all planets solid?

Why are the natural satelites (moons) of all planets - including the moons of the gas giants - solid or rocky, and not gaseous?
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1answer
129 views

Life cycle of a gas planet?

I am interested in learning more about the (simplified) life cycle of gas planets which are not brown dwarfs (meaning less than 13 Jupiter masses). It obviously starts off with their creation within a ...
32
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4answers
7k views

Can small gas planets exist?

Most of the known gas planets (Jupiter, Saturn, etc.) are huge. They are even called "gas giants". is it possible to exist a gas planet around the size of Earth? If yes, why; if no, why?
12
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1answer
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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 ...
12
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1answer
21k views

What will happen when landing on Jupiter?

Jupiter is a gas giant, so landing on it will not be like landing on Earth, our Moon or Mars etc., as it does not have a solid surface like these. If we have a hypothetical spaceship or probe landing ...
42
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1answer
5k views

Why does the Sun have different day lengths, but not the gas giants?

The Sun's rotation period varies from about 25 days at the equator to about 38 days at the poles. As I understand it, this is because the Sun is not solid, and because of the way centripetal force ...
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2answers
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Is there a gas giant orbiting TRAPPIST-1?

I would like to know if besides these planets, astronomers have discovered a gas planet like Jupiter in this system and if on these planets could exist life without a comet protector like Jupiter does ...
12
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1answer
249 views

Is there any evidence that the Gas Giant planets in our solar system are experiencing orbital migration?

Planetary migration is defined by Lubow and Ida (2010) in their article Planet Migration as the process by which a planet’s orbital radius changes in time. The main agent for causing gas giant ...
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2answers
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Why does each and every planet of our solar system have an unique axial tilt angle?

Why do planets have an axial tilt? From the above image we can see that each planet's axial tilt angle varies and differs from the others. What was the cause of this, was this from the beginning of ...
8
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1answer
403 views

If the fifth gas giant in the early Solar System was completely ejected, where would it be now?

I've read about the possible 5th gas giant in the Solar System, and about its ejection about ~100 million years after the formation of the Solar System. However, I have not seen anything about its ...
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2answers
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Maximum and minimum gas giant & ice giant densities

I'm working on a star system generator for a game; I'd like its results to be plausible but they needn't be super-realistic. I've got the orbital distances and masses of each body in the system, and ...
4
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2answers
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Collision of asteroid and gaseous planet - what would happen

What happens when asteroids (or other small bodies) "collide" with a gas planet? In my head it would either go through it or just stay "inside" it due to the strong gravity. I tend to believe in the ...
10
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1answer
2k views

Why do Uranus and Neptune have more methane than Jupiter and Saturn?

So the standard theory of the solar nebula is that in the region of the gas planets, ice and rock could condense to form planetesimals, which could then accrete hydrogen and helium to form the gas ...
6
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1answer
151 views

Aren't there any rock or similar firm material on/in the gas giant planets?

Aren't there any rock or similar firm material on/in the gas giant planets? What happens if a rock asteroid hits one of these planets? Shouldn't the rock accumulate in the center of the planet due to ...
5
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3answers
776 views

Why do the gas giants in the Solar System have comparatively large orbits compared to the inner planets?

Ever since I observed the depictions of the Solar System, I was obsessed with the question of why the gas giants (outer planets) have very large orbits, compared to the planets that are closer to the ...
5
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2answers
113 views

How to calculate the frequency of a gas giant eclipsing the sun from a moon?

Say you have a moon around a gas giant which goes around a star. If the moon has an inclination of around 0° relative to the gas giant's orbit, the gas giant will eclipse the star every orbit of the ...
4
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1answer
292 views

Are gas giants supported by thermal pressure?

I've heard gas giants are supported because there is an equilibrium between thermal pressure and gravity. That is, if Jupiter were to suddenly begin compressing, temperatures would increase to the ...
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1answer
121 views

Terminology question: gas giant vs gas planet

While not exactly the most exciting question, I'm wondering: is there any real, semantic difference between a gas planet and gas giant, or are the two terms used interchangeably by most in popular ...
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2answers
313 views

What would happen to a gas planet if its core mass goes beyond the Chandrasekhar limit?

Hypothetically, let's say we had a gas giant that continued to accrete mass. I've heard that the cores of gas giants are electron degenerate. So if the planet continued to accrete mass and the core ...
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2answers
184 views

Can hot Jupiters cause solar flares?

I'm very new at Astronomy, and my knowledge is sparse. I've tried to be conscientious about my Wikipedia research but there's going to be a lot of things I don't know. Thanks for your patience. ...
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Is there a term for asteroseismology as applied to giant planets?

Giant planets such as Jupiter have oscillations which enable analyses using the techniques of asteroseismology, for example Gaulme et al. (2011) detected global modes on Jupiter via radial velocity ...