d'oh. Spoke too soon...

Well, at least you posted something - although it *still* doesn't respond to the magnetic field question that you've been promising for 14 days now and claim you've had all along. Not only that, but it's so full of errors I barely know where to start. Not trying to be nasty or anything; it's just that it is.


Let's start with this: nothing you post here constitutes a "numerical simulation". It's still just a bunch of 7th grade formula plugging, and in order to do it you have tossed out most of the important variables. The link you reproduce to an actual numerical simulation (the link originally provided by me) which does include all of this stuff arrives at the opposite conclusion that you do.

No matter; there's plenty of other errors to look at.

First, you attempt to calculate the gravity at the surface of a sphere of fixed mass as the radius changes from half a light year to the orbital radius of Mercury. Ok, so far so good (wow - an actual correct answer).

Then you attempt to also calculate the pressure, and this is where the wheels come off. Firstly, you can't make the assumption that the pressure is constant throughout the sphere at all times. Although it might be at first, it certainly won't be later on - that's sort of the whole point of the hydrostatic equilibrium equations.

Secondly, you can't figure out the pressure by dividing the mass by the volume. That would give you the density, not the pressure.

Kilograms are not a unit of force - they're a unit of mass. For cosmological purposes, the difference is sort of important.

In order to determine the pressure, you'd need to use something like the ideal gas law:

P = nRT/V

Which is sort of problematic for you: since you're assuming the temperature to be infinitessimally close to absolute zero (another variable you don't want to deal with, but which is very important), you'd have a pressure of, well, zero - which of course is the opposite of what you want.

So now we don't have any sensible numbers at all here - but let's be generous and assume that, in your calculations, we can just call 1kg = 10N to make everything square again (this is of course complete baloney, but hey, who's counting? It's extremely generous in your favor, also).

Using that with your own numbers yields a value for "P", what you claim is the initial pressure, of:

2.3 x 10^-15 Pa

and your claimed pressure when the cloud has collapsed to a radius equal to the orbit of Mercury of:

2.3 Pa

Just to be clear, that last figure is:

.000023 Atmospheres

So, even taking your own ludicrous mathematics at face value and supplying generous additional baloney required to fill in the blanks, you still end up concluding that this gas cloud, by the time it's shrunk to within the orbit of Mercury, is going to have gravity at its surface a quarter of Earth's surface gravity, but pressure only .002% of the air pressure at the Earth's surface.

And yet you conclude that this pressure is sufficient to prevent the cloud from collapsing? If that were true, the "gigantic" air pressure right here would cause all of the air on Earth to be blown away into space. Personally, I'm quite happy that you're still off by several orders of magnitude.

Regards
Krill