Questions tagged [nebulae]
19 questions
23
votes
2 answers
How dense are nebulae?
How functionaly dense are nebulae? Are they so sparse they are only visible from an interstellar or intergalactic perspective or would you be unable to see your hand in one?
Do they vary widely in density, between nebulae or even within a single…
Suni
12
votes
4 answers
Names, maps for Milky Way dust clouds? (Dark Cloud Constellations)
There is a nice image of the Milky Way, labeled with constellations, at 360°x45° panorama with constellations:
It leads me to wonder how much we know about the Great Rift, Coalsack and other prominent dust clouds that obscure the stars in the…
nealmcb
- 471
6
votes
4 answers
How is it that some nebulae are rotating and others are not?
First, I should make it clear that this isn't a question about angular momentum (unless I may have completely missed something). It is my understanding that a nebula must have some inherent initial spin before collapse to form a solar system (and if…
Nate
5
votes
1 answer
How are new nebulae being created?
The nebulae we see in the night sky are forming new stars.
The stars are eating up the nebulae and there is no obvious process in which those nebulae are being created to compensate for that.
Shouldn't the universe have run out of those nebulae a…
Hermann Ingjaldsson
4
votes
1 answer
Could a bipolar nebula be produced by a time gradient?
M2-9 is an example of a bipolar nebula that resembles two back-to-back rocket nozzles. Is it possible that this shape (somewhat unusual for an explosion) is the result of a time gradient? A rotating neutron star having collapsed and preserved its…
Steve Kohl
- 51
3
votes
2 answers
Why isn't all of the dust in a nebula used in the formation of a star?
I was watching a show on discovery and according to it, in a nebula the dust and gases slowly come together and as the gravity increases and the pressure rises in the core the gases fuse together and a star is born and the rest of the left over dust…
Deiknymi
- 2,271
3
votes
2 answers
Simulating nebulae
How can we simulate nebulae shapes computationally?
What are the governing equations or forces acting on nebulae? Is it suitable to just use Navier Stokes fluid dynamics and solar winds or is there also significant effects from gravity?
What causes…
dubious
- 131
3
votes
1 answer
What is wrong with our Cloud chamber setup?
A nearly identical question has been asked before on this topic, but that thread did not help us any further.
Me and a classmate built a cloud chamber in order to see elementairy particles (we aren't working with a radioactive source). We use a very…
2
votes
2 answers
Distinguishing Gamma-rays and stars from each other in nebulas
How do you tell the difference between a gamma-ray burst and a star just from a picture of a nebula, in which it cannot flash on and off here and there?
William
- 31
1
vote
0 answers
Analytical models for planetary nebula expantion
I'm doing an astrophysics project where we measure the properties of a planetary nebula (NGC 7662) where we need to determine it's electronic temperature, electronic density and expansion speed.
I'm trying to find some (simple) analytical models…
Jhon Jack
- 17
1
vote
1 answer
Would an HI or HII region have a color?
That is, if we were approaching an HI or HII region in a spaceship, would the cloud have a color visible to the naked eye? Of the HI region, Wikipedia says:
These regions do not emit detectable visible light (except in spectral
lines from…
alkah3st
- 153
1
vote
0 answers
If entropy is positive, then why do stars form from nebulae?
Sorry if I have so many misconceptions with this questions, but I guess that's the point of asking questions.
If entropy, the measure of disorder, is always positive, then how come a star could form from a nebula?
Considering that a nebula is made…
David
- 27
0
votes
0 answers
Does a star that is far from any galaxy tend to rotate slower?
I'm wondering whether the rotation of a galaxy and the buffeting of the gas and dust within it by light and stellar wind and pressure waves makes nebulae or gas clouds in galaxies have more angular momentum than those in intergalactic space, and…
0
votes
3 answers
If the inclination of a cloud of oxygen in outer space is to diffuse, then how do nebulae form?
If a cruise ship-size object in outer space were surrounded by a spherical cloud of oxygen, and there were no other bodies exerting significant gravitational force in the vicinity, would the cloud of oxygen be held in place by the gravity of the…
Skallod
- 101
0
votes
0 answers
Solving coupled integral + differential equations for ionoization and combination of gases near a star
The following set of coupled differential + integral equations appear regularly in the literature (e.g Osterbrock, "Astrophysics of Gaseous Nebulae and Active Galactic Nebulae"):
$ n_H(r) \int_{\nu_0}^\infty \frac{L_v}{(4 \pi r^2 h \nu)}…
Facieod
- 61