Newton's Demon

[dougettinger]

Newton invented gravity but was very uncomfortable about why this force operated at great distances. One could say that his concept of gravity possessed a demon similar to the one that Maxwell identified in his entropy experiments. But Newton’s Demon is very special. The demon possesses another mysterious property of sorting materials inside a well mixed homogeneous interstellar cloud of molecular matter to create planetary cores of iron and other heavy metals. The nebula hypothesis for solar system creation depends on gravity to perform this sorting and gathering of much less than one percent of a protostar’s disk of materials. It is presumed that most of the heavier metals are eventually captured by the protostar. So how do the planets end up proportionally with 20 times more heavier elements by mass than the entire solar system?

Doug Ettinger
Pittsburgh, PA
01/18/2011

[Chris Peterson]

The nebula hypothesis for solar system creation depends on gravity to perform this sorting and gathering of much less than one percent of a protostar’s disk of materials. It is presumed that most of the heavier metals are eventually captured by the protostar. So how do the planets end up proportionally with 20 times more heavier elements by mass than the entire solar system?

Most likely because other forces are at work. Gravity is the energy source that drives the system, but you can't neglect radiative forces, fluid dynamic forces, the effect of various gradients, electromagnetic forces, and probably many other factors. Certainly, the models that are used to simulate planetary system formation do not limit themselves to just gravitational fields.

[dougettinger]

Radiative forces do not come into play until the protostar becomes sufficiently dense and hot.

Gradients of density of the hard vacuum may initiate the motions of particles and produce a central source for gravity for the overall protostar disk. Smaller gradients inside this larger gradient should become more homogeneous as mixing from the larger gradient occurs.

It is assumed that the IMC is cold and condensing. Since no plasma exists very little electromagnetic forces should occur except for the random weaker static charges.

I am curious how the fluid dynamic forces would be applied. Are there any general equations that may be applied for the computer modeling ?

Doug Ettinger
Pittsburgh, PA
01/18/11

[Chris Peterson]

Radiative forces do not come into play until the protostar becomes sufficiently dense and hot.

Radiative forces are always in play. They simply increase as the core becomes hotter.

Gradients of density of the hard vacuum may initiate the motions of particles and produce a central source for gravity for the overall protostar disk. Smaller gradients inside this larger gradient should become more homogeneous as mixing from the larger gradient occurs.

That is not obvious. Because you have energy present in the system, you also have a mechanism for maintaining various gradients, including mass density gradients.

It is assumed that the IMC is cold and condensing. Since no plasma exists very little electromagnetic forces should occur except for the random weaker static charges.

You may underestimate the impact even relatively small fields can have in this sort of environment.

I am curious how the fluid dynamic forces would be applied. Are there any general equations that may be applied for the computer modeling ?

Fluid dynamics are the main component of stellar system formation models. Without applying the standard equations of fluid dynamics, you wouldn't even get accretion discs. This is probably the single most important factor in determining system dynamics (other than gravity, which provides the energy).

[dougettinger]

These few questions may be outside your realm of knowledge, Chris. I do not know how accessible the input data is for computer modeling of protostar or solar system genesis. For fluid dynamic considerations is Bernoilli's Equation, Euler's Equations or the Navier-Stokes Equations utilized ? Are the protostar disk materials for this modeling considered to be viscous or inviscid flows ? Compressible or incompressible flows ? Turbulent or laminar flows ? Electrically conducting flows ? Does the computer modeling use equations for gravity, fluid dynamics, thermodynamics, electromagnatic forces, and radiative forces simultaneously ? We may be closer to being God than I ever thought was possible.

Doug Ettinger
Pittsburgh, PA
01/19/11

[Chris Peterson]

These few questions may be outside your realm of knowledge, Chris. I do not know how accessible the input data is for computer modeling of protostar or solar system genesis. For fluid dynamic considerations is Bernoilli's Equation, Euler's Equations or the Navier-Stokes Equations utilized ? Are the protostar disk materials for this modeling considered to be viscous or inviscid flows ? Compressible or incompressible flows ? Turbulent or laminar flows ? Electrically conducting flows ? Does the computer modeling use equations for gravity, fluid dynamics, thermodynamics, electromagnatic forces, and radiative forces simultaneously ?

I don't know the specifics of the modeling used. I do know something about this sort of modeling in general, and it probably applies here. Models can have physical components and they can have empirical components. Everybody likes physical components and prefers avoiding the empirical (but this isn't always possible). You would expect a model that includes fluid dynamics to utilize all the available physical theory, which includes the equations you mention. The other stuff you bring up- viscous vs nonviscous, laminar vs turbulent, etc will be outputs of the model, not inputs or something to be considered.

And yes, AFAIK stellar system models consider all the factors you list. Fluid dynamics is just one process. The model won't be accurate without including all the physical processes presumed to be factors. Models generally improve in three ways: the physics get better, and the number of factors solved for increase, and the resolution (time and space) improve.