Gas Behaviour in Space: Exploring the Mysteries of Gaseous Matter Beyond Earth

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In summary, gases in space form structures held together by gravity and resisted by pressure. If their self-gravity is high enough, they can collapse to form planets and stars. If their internal pressure is too high, they remain as clouds of plasma, atoms, or molecules. The condition for cloud collapse is called the Jeans instability. It is possible for there to be a huge region of space comprised purely of gas, as the universe was before the first stars formed. The critical size of a cloud before it collapses can be calculated using the Jeans instability equations. Interstellar molecular clouds, which trigger stellar formation, can reach hundreds of light-years in size. However, the space between stars is not a hard vacuum and can have a density of one atom
  • #1
Anon5000
What happens to gases in space?

Do they just dissapear? (Yes yes, yawn) Or can they make up a region of space, and stick together via gravity?

And what about Jupiter and other gas giants? How do they work, if in space, all gases tend to just shoot out and spread into an even film?
 
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  • #2
Gasses in space form structures held together by gravity and resisted by pressure.

If their self-gravity is high enough to overcome internal pressure, they collapse to form denser structures - such as planets and stars.

If their internal pressure is too high (e.g. because the gas is hot, and/or there isn't that much of it in the first place), they remain as clouds of plasma, atoms, or molecules.

The condition for cloud collapse is called the Jeans instability. Wikipedia has a good article on it.
 
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  • #3
Bandersnatch said:
Gasses in space form structures held together by gravity and resisted by pressure.

If their self-gravity is high enough to overcome internal pressure, they collapse to form denser structures - such as planets and stars.

If their internal pressure is too high (e.g. because the gas is hot, and/or there isn't that much of it in the first place), they remain as clouds of plasma, atoms, or molecules.

The condition for cloud collapse is called the Jeans instability. Wikipedia has a good article on it.

But it is possible for there to be a huge region of space comprised purely of gas? (That lasts, outside of longterm redshift, decay, etc)
 
  • #4
What does 'huge' mean?

In any case, that's what the whole universe was like before the first stars formed, so I guess that's huge enough.
 
  • #5
Bandersnatch said:
What does 'huge' mean?

In any case, that's what the whole universe was like before the first stars formed, so I guess that's huge enough.

Yep, good enough for me.

No I say huge because, again, since the gas expands so much when exposed to zero pressure and vacuum, I would expect it to be a huge area of sparse, but nevertheless "packed" gas. And it would probably be in the middle of nowhere since otherwise it'd get stuck to a planet.
 
  • #6
Look up the Jeans instability equations, and specifically Jeans length. It relates the critical radius of a cloud depending on particle mass, gas density, and temperature.
You can then try plugging in various values and see what is the critical size of the cloud (before it collapses).
For interstellar molecular clouds, whose eventual collapse triggers stellar formation, and which are extremely tenuous by Earth standards (on the order of ~10^5 particles per cm^3, similar to industrial-grade vacuum, or 'atmosphere' density on the Moon), the clouds can reach hundreds of light-years in size.

Below is an example of a smaller one, mere 25 ly across, that you can see with your naked eyes on a dark night.
300px-Orion_Nebula_-_Hubble_2006_mosaic_18000.jpg

Stars are already forming in its densest regions, heating up the surrounding gas and dust.
 
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  • #7
Anon5000 said:
No I say huge because, again, since the gas expands so much when exposed to zero pressure and vacuum
The space between the stars is not a hard vacuum though. The interstellar medium is has between one atom in a cubic meter to a million in a cubic centimeter. Hotter gasses also tend to be ionized, so in that case, EM forces can play a role as well as gravity.
 

1. What is the behavior of gas in space?

The behavior of gas in space is quite different from its behavior on Earth due to the lack of atmospheric pressure and gravity. In the vacuum of space, gas molecules move freely and rapidly, creating a highly dispersed and dynamic system. This can lead to phenomena like diffusion and turbulence.

2. How do gases behave differently in microgravity environments?

In microgravity environments, gases behave differently due to the absence of gravity. Without the force of gravity to hold them down, gas molecules can spread out evenly and form a spherical shape. This also eliminates convection currents, making the behavior of gas more uniform and predictable.

3. Why is studying gas behavior in space important?

Studying gas behavior in space is important because it can help us better understand the fundamental laws of physics and how they apply in different environments. It also has practical applications, such as improving our understanding of propulsion systems for space travel and developing new technologies for gas separation and storage.

4. Can gas exist in space without a container?

Yes, gas can exist in space without a container. In fact, the vacuum of space can be considered the ultimate container for gas. While there is no atmospheric pressure to contain gas, it can still exist in space due to its high energy and constant motion.

5. How does the behavior of gas in space impact the formation of planets and stars?

The behavior of gas in space plays a crucial role in the formation of planets and stars. As gas molecules come together due to gravitational forces, they can form dense clouds that eventually collapse and give birth to new celestial bodies. The study of gas behavior in space can provide insights into this process and help us understand the formation and evolution of our own solar system.

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