Questions tagged [interstellar-medium]
Questions about the gas that lays between stars in galaxies.
74 questions
5
votes
1
answer
428
views
Do liquids exist in the interstellar medium?
Am not asking about planetary/meteorite surfaces and am restricting myself to the interstellar medium
edit:
by interstellar medium I mean, the following:
"Interstellar medium (ISM) is the matter ...
- 83
0
votes
1
answer
207
views
Could there be massive charged “rivers” in interstellar space?
Some suggest that there might be currents of charged particles moving at 0.98c in interstellar space. Since this is tainted by association with the crack “Electric Universe” cosmology, my first ...
- 1,018
1
vote
0
answers
46
views
Explanation of the isochoric and isobaric instability conditions of interstellar medium gas clouds [duplicate]
The question Why are there no ISM clouds with temperatures between 100 and 6,000K? has an accepted answer of the form:
Let $n$, $T$, and $x_i$ be the number density of hydrogen, the temperature of ...
- 30.7k
10
votes
1
answer
441
views
Why are there no ISM clouds with temperatures between 100 and 6,000K?
In the interstellar medium, there are several different diffuse phases of gas, distinguished by their density and temperature. Specifically, the cold neutral medium has temperatures from ~50-100 K and ...
- 3,166
2
votes
1
answer
234
views
Examples of astrophysical objects NOT in virial equilibrium?
Astronomers always talk about astrophysical objects being in virial equilibrium (e.g., a stellar system, or a disk of gas within a galaxy, etc.). But I never hear about thermodynamical equilibrium.
...
- 723
10
votes
2
answers
870
views
Would a spaceship have to evade interstellar clouds?
Apparently, there are clouds of "dust" between the stars. Would a starship have to fly around those clouds, trying to find "tunnels" between clouds, or are the interstellar clouds harmless for a ...
user2233
5
votes
2
answers
575
views
What is the word for space that is in the solar system, but outside the heliopause?
Wikipedia says the definition of interplanetary space is
the region dominated by the interplanetary medium, which extends out
to the heliopause where the influence of the galactic environment
...
- 1,569
1
vote
0
answers
141
views
Virial coefficient when computing dynamical mass enclosed by a rotating galactic disk of gas
Suppose I have a large thin disk of rotating gas in a galaxy -- the disk has a maximum inclination-corrected $V_{max}$ and a maximum radial extent of $R_{max}$ corresponding to that $V_{max}$ ...
- 723
14
votes
5
answers
7k
views
How cold is interstellar space?
The vastness of space brings me a sense of chilliness even though I have never experienced it, although I wish to. Just how cold is interstellar space (on average)? How is this even measured? I mean ...
- 1,093
4
votes
1
answer
87
views
Population of excited H levels in a Strömgren Sphere
In chapter 2.2 of Astrophysics of Gaseous Nebulae and AGN Ostriker and Ferland claim that, as far as ionization is concerned, one can assume all atoms to be in the ground state in a Strömgren Sphere ...
- 301
6
votes
1
answer
735
views
What would the night sky look like if the interstellar medium didn't exist to absorb or block light?
I was curious about how much brighter it would be and how much further we could see.
- 874
4
votes
1
answer
460
views
Why dust is optically thin in Far Infrared wavelengths?
What is the actual meaning of the statement 'Dust is optically thin in the Far Infrared (FIR) over most of the Galaxy'? Kindly Help
- 503
5
votes
1
answer
161
views
What is the distribution of organic compounds in the Milky Way Galaxy?
I imagine the answer is unknown for the entire galaxy, but I would appreciate a notion of the scales and locations of regions where astronomers have ventured at least a guess to the distribution of ...
- 151
10
votes
2
answers
3k
views
Lack of objects between heliopause and Oort cloud?
If we take a look at a logarithmic scale of the Solar System, there appears to be a large gap between the heliopause and the Oort cloud:
Why is that? There are some objects in the gap, but why are ...
- 8,196
1
vote
2
answers
112
views
Dust mass-loss rate from a massive star given a set of parameters?
I've been looking for examples at how mass-loss rates are determined.
I'm studying a circumstellar dust shell ejected from a Wolf-Rayet star. I have some parameters like, expansion velocity of the ...
- 69
8
votes
2
answers
316
views
Can dark matter decrease the Jeans length?
I am wondering if there are any models of interstellar cloud collapse out there which take dark matter into account.
If dark matter has local perturbations or density fluctuations, then that may be ...
- 383
6
votes
1
answer
414
views
Speed of light through the ISM and Wavelength
Articles written about fast radio bursts describe the signal's short-wavelength components arriving before its longer-wavelength components, suggesting energy-dependent time delays in the interstellar ...
- 499
4
votes
1
answer
924
views
Why is [O III] a good density probe in interstellar medium?
According to Draine in his book "Physics of the interstellar and intergalactic medium" (page 210/211) and Caltech [O III] line ratio's (amongst others) are a good density probe, but I cannot really ...
- 216
1
vote
2
answers
209
views
How would vehicles travel through the interstellar medium with its such low density?
I've heard from a number of different places that the density in the interstellar medium can have an average of 1 atom per centimeter cubed. Perhaps I have a wrong understanding of what 'nothing' is (...
- 111
20
votes
3
answers
4k
views
What is the difference between gas and dust in astronomy?
Is there a strict difference between gas and dust?
In Earthly environment most things become gaseous if heated enough. The temperature of interstellar medium seems to range mostly between 10 and 10 ...
- 11.5k
15
votes
3
answers
3k
views
Why is the interstellar medium so hot?
On this link, it states the following: "large assemblies of galaxies that are permeated by even larger amounts of diffuse gas. With temperatures of 10 million degrees or more".
How are these ...
- 253
9
votes
1
answer
138
views
Do we live in a galactic bubble?
I have heard a certain statement, which can be summarized succinctly into "we live in a local bubble", implying that solar system is located in an intestrellar dust underdensity region.
This region ...
- 2,749
13
votes
1
answer
585
views
Sources of Turbulence in the ISM
What sources of turbulence exist within the Interstellar medium (ISM)? Which ones are physically the most important for newly forming stellar systems?
- 5,993
15
votes
1
answer
598
views
How does interstellar matter density vary?
Answer to my question partially answers this one, about density of intergalactic matter and matter within galaxy:
But it is mostly a hot, ionized void. How void? The density of the intergalactic ...
- 6,289