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 Discussions General Interstellar Me... | |
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Interstellar Medium Temperature ?
Posted: 17 Feb 08 7:42 AM |
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Hello !
What is the temperature of the Interstellar Medium ? A high school student asked me
Could any one of you, help me prepare an answer to him ?
This is my first participation to Dubai Astronomy Group Forum.
Best Regards,
Naceur
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Re: Interstellar Medium Temperature ?
Posted: 20 Feb 08 2:08 AM |
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Temperature of the Interstellar Milieu or "vacuum"?
At the scale of the entire Universe, the temperature is around 2.73K.
That however relates to all the Galaxies and space between them. The Image A shows a view of our beautiful Univers :
The interstellar environment, on the other hand, relates to one galaxy among billions of other galaxies which make our Universe, the Image B is a zoom of Image A.
The interstellar Medium is the space between stars of the SAME and ONE galaxy. As you could see bellow, this Interstellar Milieu is not empty as one could think
This image ( Image C) is a zoom of images such as (B).
Thanks to observations, calculations and, experimental simulations in laboratory, one knows quite well that the Interstellar Milieu accounts for at least 10% of the mass of a galaxy and is composed of gas and dust : Image D bellow show some details:
The Interstellar Milieu (ISM) comprises at least three kinds of named areas called "phases":
- 1 Hot phase (a few millions K),
- 1 tepid phase (a few thousands K) and
- 1 cold phase (a few tens K)
The relative "weights" of the three phases are not elucidated perfectly yet.
The chemical composition of the Interstellar Milieu depends on the nature of the phase and on its density.
It is primarily atomic in the diffuse clouds and it is molecular (gas) and solid in the dense clouds.
In short, the temperature of the Interstellar Medium is at least equal to a few tens of K. This Milieu contains matter under various states and, is a theater of a important and interesting physical chemical transformations requiring sufficient temperatures.
Listen to this
and to this
Best Regards,
Naceur Bouziani In the French Alps.
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| | Discussions General Interstellar Me... | |
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