Actually, more accurate would be to say that the particles that bounce off the bottom of the volume will not hit it hard enough and frequently enough to repel all the particles from the denser volume below. So the top boundary of that denser volume will rise, moving the bottom of the less-denser volume upwards, causing the particles in that volume to bounce slightly higher.

That is actually very misleading, to the point of being incorrect.

At the atomic level, a molecule of Oxygen falls at the same rate as an atom of Helium (about 9.8 m/(s^2), depending on altitude), so nothing really "falls harder".

What actually happens is the process of buoyancy. A He atom weighs about 16x less than an O molecule. A volume of air at specific temperature and pressure will contain the same number of particles (atoms or molecules).

If the volume contains relatively more He, the total mass of the volume will be less (lower density). If you surround this volume with volumes of higher density and place them in a gravitational field, then the sum of the pressure forces on the volume will not be in equilibrium. There will be a net force pushing the volume upwards.

At the atomic level, all the particles are falling constantly, bouncing off particles of lower layers (electrostatic repulsion), bouncing up again. At the macroscopic level, volumes of particles with lower density rise because the net forces on them are unbalanced. Back at the atomic level, particles that bounce off the bottom of the volume get an extra "push", and bounce back a bit higher.

No. While the amplitude of the velocity vector remains the same, its direction changes constantly, the result of the gravitational force.

That is exactly what it says. Or in other words: the velocity vector only changes when a net force is applied to the object.

That is the case, but here there is only one real force working (gravity). The centrifugal force that balances the orbit is not a real force, but a result of the object's velocity.

No it doesn't.
It only applies when there is no net force on the object (as the law clearly states), and in orbit there is a gravitational force that constantly changes the velocity vector.
What you are talking about is general relativity, not classical mechanics.

Well, these may well be the most extreme regions in space-time and the maths are some of the most difficult to solve (and honestly way over my head). Plus we would have to be able to marry GR and QM to fully describe black holes.

The way I see it, the vacuum fluctuations can form many kinds of virtual pairs, and when that pair consists of photons, then there is no problem at all since they always move at c and hence can escape the gravitational well (but they will be red shifted due to the extreme gravity). So most of the Hawking radiation will always be EM radiation.

Mass-bearing particles will form with the same small/limited energy from the vacuum, and their momentum and thus initial speed will be small too. In a normal gravitational well they would almost immediately fall back towards the event horizon, due to the extreme gravitation (it requires thrust for any mass to change/leave orbit, and these are not even in orbit).

In the ergosphere of a rotating black hole, nothing can remain stationary relative to the rest of the universe because that would require faster than light movement. This means particles are forced to move, even when initially stationary, and hence they gain momentum, which in turn can lead to the particle escaping the gravitational potential.

Of course, that is when only taking into account gravitational effects. The extreme magnetic fields surrounding black holes will also accelerate charged particles, and will probably have a bigger effect than frame dragging.

Erm, that's not how orbital/slingshot mechanics work. In fact, a mass-bearing particle (from a virtual pair) could never escape a stationary black hole, because it wouldn't have enough energy to do so, and normal orbital mechanics wouldn't increase its energy.

Instead, you'd need a rotating black hole with an ergosphere. This is a weird area where space-time is dragged along the black hole faster than the speed of light relative to outer space. Here it is possible to extract energy from the black hole with what is called the Penrose process, and thus the electrons/positrons may gain enough speed to escape.

Here's a less "flashy" one, a few months older:
http://www.youtube.com/watch?NR=1&v=3sCuse5TZGA

Looking at the picture of the implant, it was more like 75% op his skull cap. I don't think losing 75% of your skull would be survivable.

This is very useful to me too. Now I can finally find out where Waldo was hiding all this time...

In other news: Nearly Every NYC Crime Involves Shoes.

I'm pretty sure the semicolon should come before the closing curly brace...

The proper term is Surface Tension.

Yeah, but it contains a lot of hot air, so you can use that to drive a turbine. Unless they sell it first.

ReactOS uses the higher level libraries and services from Wine, so any improvements they make in those will improve Wine too (and vice versa).

Besides that, everyone is free to invest their time and efforts in whatever they want.

Clearly the "Fragmentation" concept is fragmentated :o)