by MarkBour » Fri Mar 09, 2018 5:11 pm
neufer wrote: ↑Fri Mar 09, 2018 2:04 pm
I see the excellent resemblance. And maybe Jar Jar's hand is even visible in the foreground.
Looking at this magnificent molecular cloud reminds me of the discussion about the hole in NGC1999 in the APOD of 2 days ago when you challenged my thinking about the possible flow of gas there. The term "gas" in our earthly context refers to a state of matter that will have a certain amount of pressure and will expand to fill empty spaces. I realize that the counterpart in an image such as this is so rarefied and so vast that it may not behave that way on any human time scale. And I gather from looking at pillars of such gas that its motions, when they can be detected, may be the opposite of my first intuition (the Hubble "Pillars of Creation" apparently are not billowing outward, but are being carved away).
But, would you agree that even at such scales, there is still a notion of pressure? A statistical drive to spread out, which is countered by gravitational attraction? As I look at an image such as today's APOD, doesn't it indicate that there are some flows in the material of the cloud? More clearly, when a bow shock forms, it indicates that a star is moving through the cloud. After such a star passes, there is turbulent flow of the gas behind it, right? Has somebody already studied this question and determined any of the dynamics of molecular clouds over long time scales?
[quote=neufer post_id=280501 time=1520604251 user_id=124483]
[quote=" https://en.wikipedia.org/wiki/Jar_Jar_Binks"] . . . [/quote]
[/quote]
I see the excellent resemblance. And maybe Jar Jar's hand is even visible in the foreground.
Looking at this magnificent molecular cloud reminds me of the discussion about the hole in NGC1999 in the APOD of 2 days ago when you challenged my thinking about the possible flow of gas there. The term "gas" in our earthly context refers to a state of matter that will have a certain amount of pressure and will expand to fill empty spaces. I realize that the counterpart in an image such as this is so rarefied and so vast that it may not behave that way on any human time scale. And I gather from looking at pillars of such gas that its motions, when they can be detected, may be the opposite of my first intuition (the Hubble "Pillars of Creation" apparently are not billowing outward, but are being carved away).
But, would you agree that even at such scales, there is still a notion of pressure? A statistical drive to spread out, which is countered by gravitational attraction? As I look at an image such as today's APOD, doesn't it indicate that there are some flows in the material of the cloud? More clearly, when a bow shock forms, it indicates that a star is moving through the cloud. After such a star passes, there is turbulent flow of the gas behind it, right? Has somebody already studied this question and determined any of the dynamics of molecular clouds over long time scales?