What Substances Exist in the Atmosphere of Our Galaxy?

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    Atmosphere Galaxy
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Discussion Overview

The discussion centers on the substances present in the atmosphere of our galaxy, specifically focusing on the interstellar medium (ISM) and the composition of matter in space. Participants explore various aspects of this topic, including the types of atoms and molecules found in the galaxy, as well as the implications for objects moving through space.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about the specific substances in the galaxy, with initial confusion regarding whether the question pertains to Earth's atmosphere or the broader galactic context.
  • It is noted that the galaxy is mostly empty space, primarily composed of hydrogen, with some helium and trace amounts of other elements.
  • One participant describes the ISM as a very thin plasma with significant variations in density, rather than a complete vacuum.
  • Discussion includes the presence of interstellar dust and its potential origins, such as from meteorites and comets.
  • Participants mention the existence of different types of hydrogen clouds in the galaxy, including HI regions (neutral hydrogen), HII regions (ionized hydrogen), and molecular clouds (hydrogen forming molecules).
  • There is a reference to recent discussions in scientific literature about hydrogen clouds entering the galaxy from intergalactic space.
  • Concerns about friction in space are raised, with participants agreeing that friction is negligible due to the sparse distribution of matter.

Areas of Agreement / Disagreement

Participants generally agree on the composition of the galaxy being primarily hydrogen and helium, but there are varying levels of detail and understanding regarding the specific types of hydrogen clouds and the implications for space travel. The discussion remains somewhat unresolved, with participants expressing differing levels of knowledge and clarity on the topic.

Contextual Notes

Some limitations in the discussion include the lack of specific definitions for terms like "atmosphere" in the galactic context and the varying interpretations of the density and composition of the ISM. Additionally, the discussion does not fully resolve the complexities of how different substances interact in space.

Pattielli
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Would you please tell me what is in there ? I mean what substances are existing ? Where can i find out some information about this ?

Thank you very much,
 
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Can you clarify your question? Do you mean Earth's atmosphere? Or do you mean what substances are present in the galaxy in general? Or our solar system? Or something else?

In general, the "galaxy" - - which includes hundreds of billions of stars, etc. - - is mostly empty space (no atmosphere at all) except for a few atoms of hydrogen scattered about.
 
Oh yes, i am so sorry, i am just really absolutely ignorant about this, that is why I didn't know how to say about what I would like to know...Honestly, i don't know..

Thanks for your help.
is mostly empty space (no atmosphere at all) except for a few atoms of hydrogen scattered about.
That is what i would like to know, and from what you explained, that means there is only hydrogens and no other atoms ?
If there is any object flying in space, there will be no frictions or if any, they will be very small, right ?

Thank you very much
 
The ISM (inter-stellar medium) is, as Phobos said, pretty close to a vaccuum. In fact, it's mostly a better vacuum than we can create here on Earth. :surprise:

However, it's not a total vaccuum, rather (for the most part) a very thin plasma. But then, looking more closely, it's actually a plasma with an enormous variation in density, even though all of it is still a very good vaccuum! :eek:

When I return to the world of decent internet connections (about 10 days), if folk are still interested, I'll post a few links (though an hour's search with Google will probably give you much of what I'd post anyway).

The composition of the plasma? Mostly hydrogen, some helium, and ~<a few % of all other elements.

Interestingly, the ISM also has a 'dust' component, made up of fine grains, of varying sizes. A small %-age of the meteorites that you see (mostly the very faint ones) are interstellar dust grains; it may be that the Stardust mission has captured a few too; we'll know in a few years' time.
 
Okay, Thank you very much and much more if you are willing to give me an answer to Where are your links ?...:sm:
 
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Pattielli said:
Oh yes, i am so sorry, i am just really absolutely ignorant about this, that is why I didn't know how to say about what I would like to know...Honestly, i don't know..

No problem - - We like explaining this stuff. :smile:

That is what i would like to know, and from what you explained, that means there is only hydrogens and no other atoms ?

When the universe first formed (roughly speaking), about 75% of all matter was hydrogen. The rest was nearly all helium and a tiny bit of lithium. So that is what you would expect to find a scattering of in empty space.

Gravity pulled together some of the denser clouds of this hydrogen-helium and formed stars. Stars jammed those atoms together (fusion) to form the heavier elements. Large stars "died" as supernova explosions which sent those heavier atoms (and created some even heavier atoms) out into space. Gravity then made new generations of stars, planets, etc.

But nearly everywhere, atoms are very thinly spread such that "outer space" is empty...a vacuum...with just a few atoms here and there.

If there is any object flying in space, there will be no friction s or if any, they will be very small, right ?

Right. Essentially no friction. Take for example, the Earth going around the sun for billions of years and still going strong.

As Nereid said, there is also some dust here and there (e.g., heavier elements that have yet to accumulate into something larger...or dust blown off comets, etc.). That is not much of a friction factor either unless you design a spacecraft that starts getting close to the speed of light...then those tiny collisions get very energetic & hazardous to space travel.
 
In the galaxy, the hydrogen sometimes groups in certain "clouds", 3 of the most notorious are the following
-HI regions: They are clouds of neutral hydrogen,the hydrogen is in form of atoms
-HII regions: Also known as emission nebulae. Composed of ionized hydrogen. For example the Pelican nebula
http://www.licha.de/AstroWeb/gallery_fullsize.php3?iBPId=177&iSOId=264
-Molecular clouds: Hydrogen forming molecules
 
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meteor said:
In the galaxy, the hydrogen sometimes groups in certain "clouds", 3 of the most notorious are the following
-HI regions: They are clouds of neutral hydrogen,the hydrogen is in form of atoms
-HII regions: Also known as emission nebulae. Composed of ionized hydrogen. For example the Pelican nebula
http://www.licha.de/AstroWeb/gallery_fullsize.php3?iBPId=177&iSOId=264
-Molecular clouds: Hydrogen forming molecules

In a recent scientific american they discussed the fact that there are clouds of hydrogen entering our galaxy from intergalactic space.
 
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Originally posted by Phobos
No problem - - We like explaining this stuff.:smile:
Oh well, it is very nice of you to do that for me...I read all of what you tried to explain, Thanks a lot,

Again, Thanks Meteor and Mee a lot, also. <<<smile>>>
 

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