Have a peek at this!!!

[renormalised (Carl)]

Originally Posted by Zaps

Individual atoms, not dust grains.

Yes, true. But it's the loss of those electrons from the atoms on the surface of the dust grains which creates the charge and the field.

[shelltree (Shelley)]

Originally Posted by renormalised

The dust is being affected not only by the starlight but also by the internal forces within the clouds, things like turbulence generated by the cooling of the materials within the clouds, as well as heating via the aforementioned starlight (the turbulence generates pressure within the clouds). Also, these clouds have been found to have very very weak non localised magnetic fields. Some of the dust grains become slightly charged due to the effects of the starlight hitting their surfaces and emitting electrons (photoelectric effect), becoming very weakly ionised, hence the magnetic fields. Plus you also have the gravitational fields of each of the clouds affecting one another...slightly for the most part, but the effect is there.

I wish I completely understood this and all other astronomy/physics related things haha.

[RobF (Rob)]

Holy megacow...!

Actually the increasing availability of stunning widefield work like this is really educational too of course - sure beats poring over those obscure Messier and NGC markings in my old Nortons...

[renormalised (Carl)]

Originally Posted by shelltree

I wish I completely understood this and all other astronomy/physics related things haha.

All you have to do is get yourself some of the basic textbooks, like Universe, and then work your way up from there. Universe isn't hard to understand and they take you through the book as though you came to the subject not knowing anything about it. So whilst it's a textbook for senior year undergraduate and graduate students, it's not hard to understand.

[shelltree (Shelley)]

Originally Posted by renormalised

All you have to do is get yourself some of the basic textbooks, like Universe, and then work your way up from there. Universe isn't hard to understand and they take you through the book as though you came to the subject not knowing anything about it. So whilst it's a textbook for senior year undergraduate and graduate students, it's not hard to understand.

Thanks for that, I appreciate it It all interests me so much but I wouldn't have the first clue of where to start so this book should be quite helpful. I also found this http://www.amazon.com/dp/1852338903/...76150_pe_ar_t3 though I'm not sure how good it would be.

Cheers,

shell

[Zaps]

Originally Posted by renormalised

Yes, true. But it's the loss of those electrons from the atoms on the surface of the dust grains which creates the charge and the field.

You have to understand that as far as atoms are concerned (or, more correctly in this case, the nuclei and "their" associated electrons), there is no surface to anything. Atoms and matter, including dust motes, is essentially nothing but "empty space".

[renormalised (Carl)]

Originally Posted by Zaps

You have to understand that as far as atoms are concerned (or, more correctly in this case, the nuclei and "their" associated electrons), there is no surface to anything. Atoms and matter, including dust motes, is essentially nothing but "empty space".

I know that.

[renormalised (Carl)]

Originally Posted by shelltree

Thanks for that, I appreciate it It all interests me so much but I wouldn't have the first clue of where to start so this book should be quite helpful. I also found this http://www.amazon.com/dp/1852338903/...76150_pe_ar_t3 though I'm not sure how good it would be.

Cheers,

shell

That is actually a very good book and if you look at books down a little bit on the page, apart from Universe, there are a number of others there that I would recommend.

[shelltree (Shelley)]

Originally Posted by renormalised

That is actually a very good book and if you look at books down a little bit on the page, apart from Universe, there are a number of others there that I would recommend.

Awesome, thanks for the help mate, might be doing a bit of book shopping soon then

[renormalised (Carl)]

Originally Posted by shelltree

Awesome, thanks for the help mate, might be doing a bit of book shopping soon then

Anytime

If you have any trouble with the theory, let me know and I'll give you a hand with it

[Zaps]

Originally Posted by renormalised

I know that.

No offense intended good buddy, but from your earlier reply to me it appeared as if you didn't know that.

Yes, true. But it's the loss of those electrons from the atoms on the surface of the dust grains which creates the charge and the field.

My italics.

In particle physics (and elsewhere), electrons are generally accepted to be point sources to all intents and purposes, and the same can almost be said about the far more massive atomic nuclei, so in effect there is no surface to an atom.

And, as far as colliding particles are concerned, there is no grain of dust: The atom it interacts with can comprise any part of that mote, be it on the surface or right smack in the middle.

Once you are in the realm of the atomic and the sub-atomic, human world dimensions are no longer meaningful and should be ignored.

Like I said, no offense intended. It's just sometimes you can learn sumpin' new, even from old guys like me!

[renormalised (Carl)]

Originally Posted by Zaps

No offense intended good buddy, but from your earlier reply to me it appeared as if you didn't know that.



My italics.

In particle physics (and elsewhere), electrons are generally accepted to be point sources to all intents and purposes, and the same can almost be said about the far more massive atomic nuclei, so in effect there is no surface to an atom.

And, as far as colliding particles are concerned, there is no grain of dust: The atom it interacts with can comprise any part of that mote, be it on the surface or right smack in the middle.

Once you are in the realm of the atomic and the sub-atomic, human world dimensions are no longer meaningful and should be ignored.

Like I said, no offense intended. It's just sometimes you can learn sumpin' new, even from old guys like me!

No offense taken. However despite the fact that there's really nothing there (adds a whole new meaning to the term "airhead"!!!), the photons that strike that dust grain acts as if they've bounced off a brick wall. Remember....Heisenberg. Where you get PE, the old electron gets the shaft and booted out of the house

[Zaps]

Originally Posted by renormalised

No offense taken. However despite the fact that there's really nothing there (adds a whole new meaning to the term "airhead"!!!), the photons that strike that dust grain acts as if they've bounced off a brick wall. Remember....Heisenberg. Where you get PE, the old electron gets the shaft and booted out of the house

The incoming photons only interact with, and are absorbed by (rather than "bouncing off" anything), an electron shell and then an electron is emitted.

But I was actually addressing your assertion that the incoming energy (photons) collide with and bounce off the atoms on the outside of the dust mote, when in fact they could and do interact with any of the atoms within it.

Hey Carl, I laughed when you referred to Heisenberg, because I once met the man after a lecture back in the early '70s, and for years I was on good terms with his son, although I've since had no contact with that particular Heisenberg in more than a decade.

Science can indeed be a very small world at times!

[renormalised (Carl)]

Originally Posted by Zaps

The incoming photons only interact with, and are absorbed by (rather than "bouncing off" anything), an electron shell and then an electron is emitted.

But I was actually addressing your assertion that the incoming energy (photons) collide with and bounce off the atoms on the outside of the dust mote, when in fact they could and do interact with any of the atoms within it.

Hey Carl, I laughed when you referred to Heisenberg, because I once met the man after a lecture back in the early '70s, and for years I was on good terms with his son, although I've since had no contact with that particular Heisenberg in more than a decade.

Science can indeed be a very small world at times!

Yes, that's what happens with PE. The electron shell absorbs the photon and the electron in the shell gets the heave ho. PE occurs with short wavelengths in the Vis' or UV end of the spectrum, as you would know. Same with ionisation, get the right photon come in and the electron gets a permanent eviction, although ionisation can occur with incoming radiation of any wavelength. Where you get the slight EM field on the surface of the dust grain coming from is when electrons get jangled loose but the grain is not completely ionised. That, and as I said in my original post, slightly heated. The emitted energy is usually as IR or MW. That's why they use IR cameras/photometers to measure the IR and radio telescopes for MW radiated by the bok globules...it's one way they can measure the field potential and a number of other characteristics of the clouds.

Come to think of, my original way of putting it was incorrect, but I think you can see where I was coming from...bounce wasn't a good expression

Where did you get to meet Heisenberg?? That would've been interesting to say the least!!! What is/was your field of study??

[Zaps]

Where you get the slight EM field on the surface of the dust grain...

There really is no "surface" when referring to the atomic and sub-atomic aspect.

By my recollection, I met Heisenberg after a lecture at Harvard in the early '70s. It won't have been later as he died sometime in the mid '70s. At the time I was at a "competing" institution, but the lure of hearing the man speak was just too compelling.

[renormalised (Carl)]

Originally Posted by Zaps

There really is no "surface" when referring to the atomic and sub-atomic aspect.

By my recollection, I met Heisenberg after a lecture at Harvard in the early '70s. It won't have been later as he died sometime in the mid '70s. At the time I was at a "competing" institution, but the lure of hearing the man speak was just too compelling.

I actually had surface in inverted commas....I must've deleted for some reason. But that's what I meant, as you have put it.

Little bit of academic competition never hurt anyone....unless it meant $$$$ for the competing institutions

[shelltree (Shelley)]

Originally Posted by renormalised

Anytime

If you have any trouble with the theory, let me know and I'll give you a hand with it

Thank you so much, I appreciate it!!

[renormalised (Carl)]

Originally Posted by shelltree

Thank you so much, I appreciate it!!

Sure, anytime