Re: [Vo]:Black Holes from Newtonian Gravity? - discs.gif

[Robin van Spaandonk]

In reply to  Michel Jullian's message of Mon, 13 Oct 2008 08:35:02 +0200:
Hi,
[snip]
>The BH being a relatively small object, and there being
>near-continuous collisions in the accretion disk, it seems to me that
>matter from the disk attracted to the BH and missing it can make their
>closest approach from basically all directions (in 3D, not just 2D),
>and therefore get slingshot-ejected in all directions. 

Agreed.

>Hence my
>hypothesis that only that which is ejected fastest and closest to the
>polar direction, a small minority, does not fall back on the disk

Why? What is special about the polar direction? I can agree with the "fastest",
but not with the direction.  In fact if the slingshot effect were responsible,
then I would expect to see most matter primarily ejected in the plane of the
accretion disc, with progressively less ejected as the ejection angle with the
disc increases, and the *least* ejected in the polar directions. Now you might
easily argue that when matter is ejected within the disc, it usually gets
"thermalized" (to borrow a term), and soon just once again becomes part of the
disc. However this doesn't explain why the jets are so strongly collimated, and
so narrow, and why they are *maximal* perpendicular to the disc.

What might explain it is if the jets comprise fast charged particles and the
whole thing is an incredibly powerful magnet, such that the particles are forced
to circulate around the magnetic field lines (which I think Horace says in his
theory, though I only skimmed it, so I could have misunderstood).

BTW if this is true, then they should also be incredibly strong emitters of
cyclotron radiation (though probably not coherent).

If one thinks of the empty space around the jets as a huge invisible magnetic
doughnut, with a very small hole, then the jets escape out through the holes. At
least that's how I could envisage it happening.
[snip]
Regards,

Robin van Spaandonk <[EMAIL PROTECTED]>