Molecular Cloud Bernard 163 (APOD 21 Mar 2007)

Comments and questions about the APOD on the main view screen.
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orin stepanek
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Molecular Cloud Bernard 163 (APOD 21 Mar 2007)

Post by orin stepanek » Wed Mar 21, 2007 8:51 pm

If it looks like a duck; quacks like a duck; waddles like a duck; than it must be a duck. :P http://antwrp.gsfc.nasa.gov/apod/ap070321.html But this duck lays stars instead of eggs. The cloud really is dark like the writeup says. The space around looks like it is full of dust also or is the brown coloration put in to show the darkness of Bernard's cloud? :?:
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BMAONE23
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Post by BMAONE23 » Wed Mar 21, 2007 10:01 pm

a link at the end of the explanation brings you to this image
http://antwrp.gsfc.nasa.gov/apod/image/ ... rtin_f.jpg

also an APOD
http://antwrp.gsfc.nasa.gov/apod/ap050908.html

which shows the duck in context

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orin stepanek
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Post by orin stepanek » Thu Mar 22, 2007 4:12 am

BMAONE23 wrote:a link at the end of the explanation brings you to this image
http://antwrp.gsfc.nasa.gov/apod/image/ ... rtin_f.jpg

also an APOD
http://antwrp.gsfc.nasa.gov/apod/ap050908.html

which shows the duck in context
Thanks BMAONE23; That shows all the dust around the aera. :)
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Post by NoelC » Sat Mar 24, 2007 1:15 am

A small point, but worth mentioning...

Note the caption text: "The red glow in the background results from IC 1396, a large emission nebula..."

What they're saying is that the light reddish-brown colored area shown in the APOD is mostly light from glowing gas (e.g., a mix of ionized hydrogen, oxygen, sulfur, etc.), not dust. The dust is showing up as dark areas in front of the molecular gas. Energetic starlight ionizes the gas and makes it glow. This is called an emission nebula. It's shown reddish-brown instead of deep red in the image simply because that's how the person doing the image processing chose to represent it. This sometimes happens with images created from only red and blue filtered exposures. Here's another rendition showing more the true visual deep red color of the area.

There are nebulae in the sky where the dust lights up due to reflected starlight - this is known as a reflection nebula. Most of the nebulosity around the Pleiades cluster is one such example. Dust tends to disperse blue light best, so dust reflection nebulae generally look blue.

-Noel

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orin stepanek
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Post by orin stepanek » Sat Mar 24, 2007 2:09 pm

Hi NoelC! Thanks; after reading your reply I got interested in space dust so I Asked on the Internet and came up with this.

http://researchnews.osu.edu/archive/spacedus.htm

http://en.wikipedia.org/wiki/Interstellar_dust

I didn't read it all yet but it appears that space dust is pretty important in the formation of stars and planets.
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Post by NoelC » Sat Mar 24, 2007 7:59 pm

Good links, Orin. Thanks.

One thing I've always found fascinating is that infrared light can penetrate space dust better than visible light, much the same as the way infrared imaging can be used here on Earth to "see through" smoke and fog.

Not long ago (don't have the link handy) the APOD folks published an image done in IR light of the center of our galaxy showing much more detail than we've seen with visible light, as the intervening dust was not obscuring the view nearly as much.

-Noel

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Post by BMAONE23 » Sun Mar 25, 2007 12:41 am


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Post by NoelC » Sun Mar 25, 2007 3:06 am

Yes, that first one was it. Thanks!

-Noel