by neufer » Mon Nov 24, 2008 8:17 pm
Chris Peterson wrote:bystander wrote:harry wrote:Whats in a Nebulae anyway?
As far as I know, ionized gas and dust. But, what is dust?
Is that like the astronomers definiton of metals? Anything heavier than helium?
Or is it simply unionized matter?
The latter.
unionized, adjective
1. being a member of or formed into a labor union [syn:
organized]
2. not converted into ions [syn:
nonionized]
Chris can't mean "
simply nonionized matter" cause that would include H I regions:
<<An H I region is an interstellar cloud composed of neutral atomic hydrogen (H I). These regions are non-luminous, save for emission of the 21-cm (1,420 MHz) region spectral line. This line has a very low transition probability, so requires large amounts of hydrogen gas for it to be seen. At ionization fronts, where H I regions collide with expanding ionized gas (such as an H II region), the latter glows brighter than it otherwise would. The degree of ionization in an H I region is very small at around 10-4 (i.e. one particle in 10,000). Mapping H I emissions with a radio telescope is a technique used for determining the structure of spiral galaxies. It is also used to map gravitational disruptions between galaxies. When two galaxies collide, the material is pulled out in strands, allowing astronomers to determine which way the galaxies are moving.>>
http://en.wikipedia.org/wiki/H_I_region
So Chris must mean "
organized matter" :
Chris Peterson wrote:Dust is what you get when atoms or molecules stick together (usually weakly) to form a blob of some sort, but which is not itself a single molecule. The size of dust particles has been measured in nebulas using scattering and polarization properties. Recently, some interstellar dust particles have been found in meteorites. I believe they have also been detected by particle detectors on several space probes.
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http://en.wikipedia.org/wiki/Cosmic_dust
<<Cosmic dust is a type of dust composed of particles in space which are a few molecules to 0.1 mm in size. Cosmic dust can be further distinguished by its astronomical location; for example: intergalactic dust, interstellar dust (potentially concentrated in a nebula), interplanetary dust (such as in a circumstellar disk) and circumplanetary dust (such as in a planetary ring). In our own Solar System, interplanetary dust causes the zodiacal light. Sources include comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through our solar system.>>
-----------------------------------------------------
The Blob (1958): <<A meteorite falls in the country of a small town, bringing a jelly creature. An old farmer is attacked by the alien in his hand, and the youths Steve Andrews and his girlfriend Jane Martin take him to Dr. T. Hallen. The local doctor treats carefully the blister, and asks Steve to investigate the location where they found the old man. When Steve returns, he sees the blob killing the doctor. Steve and Jane try to warn the police and the dwellers, but nobody believe on them, while the blob engulfs many people, getting bigger and bigger.>>
Lieutenant Dave: I think you should send us the biggest transport plane you have,
and take this thing to the Arctic or somewhere and drop it where it will never thaw.
[quote="Chris Peterson"][quote="bystander"][quote="harry"]Whats in a Nebulae anyway?[/quote]
As far as I know, ionized gas and dust. But, what is dust?
Is that like the astronomers definiton of metals? Anything heavier than helium?
[b]Or is it simply unionized matter?[/b][/quote]
The latter.[/quote]
[b]unionized[/b], adjective
1. being a member of or formed into a labor union [syn: [b]organized[/b]] :?:
2. not converted into ions [syn: [b]nonionized[/b]] :?:
Chris can't mean "[b]simply nonionized matter[/b]" cause that would include H I regions:
<<An H I region is an interstellar cloud composed of neutral atomic hydrogen (H I). These regions are non-luminous, save for emission of the 21-cm (1,420 MHz) region spectral line. This line has a very low transition probability, so requires large amounts of hydrogen gas for it to be seen. At ionization fronts, where H I regions collide with expanding ionized gas (such as an H II region), the latter glows brighter than it otherwise would. The degree of ionization in an H I region is very small at around 10-4 (i.e. one particle in 10,000). Mapping H I emissions with a radio telescope is a technique used for determining the structure of spiral galaxies. It is also used to map gravitational disruptions between galaxies. When two galaxies collide, the material is pulled out in strands, allowing astronomers to determine which way the galaxies are moving.>>
http://en.wikipedia.org/wiki/H_I_region
So Chris must mean "[b]organized matter[/b]" :
[quote="Chris Peterson"]Dust is what you get when atoms or molecules stick together (usually weakly) [b]to form a blob of some sort[/b], but which is not itself a single molecule. The size of dust particles has been measured in nebulas using scattering and polarization properties. Recently, some interstellar dust particles have been found in meteorites. I believe they have also been detected by particle detectors on several space probes.[/quote]-----------------------------------------------------
http://en.wikipedia.org/wiki/Cosmic_dust
<<Cosmic dust is a type of dust composed of particles in space which are a few molecules to 0.1 mm in size. Cosmic dust can be further distinguished by its astronomical location; for example: intergalactic dust, interstellar dust (potentially concentrated in a nebula), interplanetary dust (such as in a circumstellar disk) and circumplanetary dust (such as in a planetary ring). In our own Solar System, interplanetary dust causes the zodiacal light. Sources include comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through our solar system.>>
-----------------------------------------------------
The Blob (1958): <<A meteorite falls in the country of a small town, bringing a jelly creature. An old farmer is attacked by the alien in his hand, and the youths Steve Andrews and his girlfriend Jane Martin take him to Dr. T. Hallen. The local doctor treats carefully the blister, and asks Steve to investigate the location where they found the old man. When Steve returns, he sees the blob killing the doctor. Steve and Jane try to warn the police and the dwellers, but nobody believe on them, while the blob engulfs many people, getting bigger and bigger.>>
Lieutenant Dave: I think you should send us the biggest transport plane you have,
and take this thing to the Arctic or somewhere and drop it where it will never thaw.