The Blue Lagoon Nebula:
http://antwrp.gsfc.nasa.gov/apod/ap060825.html
I like it better with the stars in the foreground. The sparkle they add brings out the beauty of the nebula.
Orin
Blue Lagoon (APOD 25 Aug 2006)
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orin stepanek
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Well, the whole gas cloud isn't going to form a star, certainly... it'd be an awfully big star! 
The distribution of matter throughout is uneven, so areas with more gas have higher gravity, which pulls in more gas, etc. This is counterbalanced by the temperature of the gas: if it's too hot, gravity can't slow the particles down enough to trap them.
Often these clouds reach a sort of equilibrium, where they're pseudo-stable, until something disturbs them... say the shockwave of a supernova or the passing of a galaxy's spiral arm. This can upset the balance, stirring things up, and causing some areas to finally begin collapsing.
Heavy elements, I believe, tend to alter the lifespans of stars that have a high abundance of them; I think it shortens their 'lifespan'. But I'm not certain on that one, you'll hafta ask someone who knows what they're talking about.
The distribution of matter throughout is uneven, so areas with more gas have higher gravity, which pulls in more gas, etc. This is counterbalanced by the temperature of the gas: if it's too hot, gravity can't slow the particles down enough to trap them.
Often these clouds reach a sort of equilibrium, where they're pseudo-stable, until something disturbs them... say the shockwave of a supernova or the passing of a galaxy's spiral arm. This can upset the balance, stirring things up, and causing some areas to finally begin collapsing.
Heavy elements, I believe, tend to alter the lifespans of stars that have a high abundance of them; I think it shortens their 'lifespan'. But I'm not certain on that one, you'll hafta ask someone who knows what they're talking about.
Don't just stand there, get that other dog!
Blue Lagoon (APOD 25 Aug 2006)
Switching from one picture to the other reveals an area in the upper middle of the picture where a small portion of dust cloud seems to have changed shape. If this is is an actual change in shape it would seem to be extremely rapid movement, and I'm curious as to the cause. If it is not an actual change but is some kind of artifact of the picutres themselves I'd be curious to know what that is as well. Thanks.
Both images (with and without stars) likely originate from the same single image. That is, there is no time difference between the two images. They just took an image and then digitally removed the point light sources. In doing so some other parts of the image are changed and distorted making gas clouds appear to change, shadows come out, colors change etc.
However, if the two images were displaced by some amount of time, the particular cloud you're referring to could change that 'drastically' only if the del T was about 2 years or more. (estimating the pic spans 30 ly)
However, if the two images were displaced by some amount of time, the particular cloud you're referring to could change that 'drastically' only if the del T was about 2 years or more. (estimating the pic spans 30 ly)