Starship Asterisk*

geckzilla wrote:That wouldn't work because it's a 2d analogue.

geckzilla wrote:Coincidentally, I sprinkled a layer of cinnamon on top of some bubbling oatmeal a few moments ago, put the jar back in the cupboard, looked back at the oatmeal and it had formed dusty galactic filaments. No gravity or magnets required, just bubbles.

geckzilla wrote:

starsurfer wrote:I aim to please, glad you enjoyed the images! I really like dark nebulae and in my opinion they are underrated. For next year I want to see more amateur images of dark nebulae taken with large telescopes, most images are widefield.

The best are the ones with glowy things inside them. The recent HL Tauri press release happened within the dark blob next to Aldebaran which you can see very easily in this APOD.

BDanielMayfield wrote:But is the collapse solely due to gravity? Ann raised an interesting conjecture:

Ann wrote:Wouldn't it be interesting if it had something to do with magnetism?

I think that the magnetic field strength way out in open space would be very weak. But, during the supernova events that largely create the metals forming all this dust magnetized grains of dust particles could form, and after cooling off the oppositely polarized ends of grains of dust would tend to stick together due to magnetism. Couldn't ionizing radiation also lead to charge differences that would help space dust clump together? Electrostatic forces between small particles are enormously greater than the gravitational attraction between them.

Chris Peterson wrote:

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow.

I expect that the origin of these clouds lies in shells of material thrown off by cataclysmic stellar events like supernovas. That means that locally, they are originally sheet-like. We are going to see sheets as long and narrow, because only those that we observe largely end-on will be visible. In addition, over time, sheet-like structures will tend to collapse to rod-like structures and blob-like structures due to the actions of gravity.

Ann wrote:Wouldn't it be interesting if it had something to do with magnetism?

starsurfer wrote:I aim to please, glad you enjoyed the images! I really like dark nebulae and in my opinion they are underrated. For next year I want to see more amateur images of dark nebulae taken with large telescopes, most images are widefield.

BDanielMayfield wrote:starsurfer, wow, two most excellent postings today I had a most enjoyable lunch hour today perusing your favorite dark cloud images:

starsurfer wrote:... here is a list of some of dark nebulae I like:

LDN 673 by Adam Block: http://www.caelumobservatory.com/gallery/ldn673.shtml
Pipe Nebula by Jason Jennings: http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Sandqvist 169 by Marco Lorenzi: http://www.glitteringlights.com/Images/ ... WVpcRqS/X3
B86 by Bernhard Hubl: http://www.astrophoton.com/NGC6520.htm
LDN 1003 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
Bernes 149 by Fabian Neyer: http://www.starpointing.com/ccd/bernes149.html
Coalsack Nebula by Bernhard Hubl: http://www.astrophoton.com/coalsack.htm
Serpens Cloud by Tom Davis: http://www.tvdavisastropics.com/astroim ... 000101.htm
LDN 935 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
B142 by Bernhard Hubl: http://www.astrophoton.com/B143.htm

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow.

BDanielMayfield wrote:

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow. The large amorphous clouds may be left overs from major events, and perhaps coalescing, seem rather normal. The long narrow ones such as the one in which V1331 Cyg is developing and also other clouds in that area would seem to have been formed by some more distinct physical phenomena.

V1331 Cyg clouds.jpg

Good question. Why are so many molecular clouds long and narrow? There must be some common physical reason why this is such a common shape for these objects to condense into. Gravity is of course important, but there's got to be more than just gravity at work on them, or they would tend to be more spherical, I would think.

dlw wrote:I'm wondering why some of the molecular clouds are long and narrow. The large amorphous clouds may be left overs from major events, and perhaps coalescing, seem rather normal. The long narrow ones such as the one in which V1331 Cyg is developing and also other clouds in that area would seem to have been formed by some more distinct physical phenomena.

V1331 Cyg clouds.jpg

starsurfer wrote:... here is a list of some of dark nebulae I like:

LDN 673 by Adam Block: http://www.caelumobservatory.com/gallery/ldn673.shtml
Pipe Nebula by Jason Jennings: http://cosmicphotos.com/gallery/image.p ... lbum_id=11
Sandqvist 169 by Marco Lorenzi: http://www.glitteringlights.com/Images/ ... WVpcRqS/X3
B86 by Bernhard Hubl: http://www.astrophoton.com/NGC6520.htm
LDN 1003 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
Bernes 149 by Fabian Neyer: http://www.starpointing.com/ccd/bernes149.html
Coalsack Nebula by Bernhard Hubl: http://www.astrophoton.com/coalsack.htm
Serpens Cloud by Tom Davis: http://www.tvdavisastropics.com/astroim ... 000101.htm
LDN 935 by Antonio Sánchez: http://afesan.es/Deepspace/slides/LRGB% ... us%29.html
B142 by Bernhard Hubl: http://www.astrophoton.com/B143.htm