Accretion Definition and 65 Threads

Sorry I don't know latex so this may look a little messy. Homework Statement I'm trying to solve the equation for null geodesics of light traveling from a rotating black hole accretion disk to an observer at r = infinity. The point of emission for each photon is given by co-ordinates r, phi...

How is it formed? How do particles move on it?

Homework Statement Imagine a planetesimal sweeping up small particles from a dust cloud. Suppose the planetesimal, of mass M and radius R, is moving through the cloud at a velocity v. There are nd dust particles per m3, each of mass md (a) Derive an expression for the number of collisions per...

What is the inner radius of an accretion disc? Is it simply the radius of the smallest possible orbit of a massive particle (the marginally stable radius), 6M ?

Homework Statement A tank initially contains 100 gal of brine whose salt concentration is 1/2 lb/gal. Bine whose salt concentration is 2 lb/gal flows into the tank at the rate of 3 gal/min. The mixture flows out at the rate of 2 gal/min. Find the salt content of the brine and its concentration...

Hi, Let's say we have a white dwarf accreting material from a giant partner. How long would it typically take for the white dwarf to go supernova? Is it of the order of a thousand years? A million? Any references would be much appreciated. Thanks, San

Nice picture of quasar accretion disk---pat on back for standard cosmology in Nature The 24 July issue of Nature reports some beautiful observational work, using a polarized light filter. Actually able to SEE the hot blue accretion disk whirling around a supermassive black hole at the center of...

I have a few questions regarding these phenomena. 1. I don't quite understand what is going on in the picture. Obviously there is a spin on the black hole but why doesn't the gases get sucked straight towards the black hole. I know this is a simulated picture but I don't see how this would...

How might one detect the plane of an accretion disc of a Black Hole? Might it just be assumed, by the orbital plane of a BH binary system? http://en.wikipedia.org/wiki/Accretion_disc"

Hi! What do you know about Saturn's Nord Pole hexagon? Is sure than the Saturn's hexagon is owed to nothing else but his convection. Then we ask ourselves what fact makes the convection from the Saturn's North Pole. There are two possibilities: 1). the convection is due to a temperature...

The gravity of black holes is the same as the gravity of other objects at large distances.Are black holes really just the same as everything else? When an atomic nucleus forms from protons and neutrons energy is released, because, if it is not,then energy would not have to be put into the...

I'm doing a project on accretion disks, and I was wondering if anyone could suggest something interesting relating to their observation that I could talk about. One thing I remember reading was that accretion discs are one of the most compelling means of proving the existence of black holes...

As I understand it, it's all atomic material in the accretion disk of a big black hole, with very high orbital velocities and high density. However, the the disk is quite flat, and cooler than one would think with the velocities involved, because the material is swirling in smoothly, with...

The phnenomenon of accretion doesn't really seem to need the effect of gravity, as long as particles have different speeds, sizes and intersecting trajectories, then they'll eventually form bigger and bigger clumps of matter. These clumps don't really need gravity to remain together either, if...

Hi everyone Im trying to understand a paper(title of the thread) arxiv.org/abs/astro-ph/0404482 Just woundering what an acoustic black hole and acoustic event horizon would actually be? Is the Analogous Hawking Radiation just ascoustic osccilations in the Accretion matter? like the...