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About Philip A. Stahl
Expertise
I specialize in stellar and solar astrophysics. Can answer any questions pertaining to these areas, the spectroscopic analysis of stars – as well as the magneto-hydrodynamics of sunspots and solar flares. Sorry – No homework problems done or research projects! I will provide hints on solutions.

Experience
Have published papers on the relationship between sunspot morphology and solar flares; discovery of SID flares related to this, constructed computerized stellar models; MHD research.

Organizations
American Astronomical Society (Solar physics and Dynamical astronomy divisions), American Geophysical Union, American Mathematical Society, Intertel.

Publications
Solar Physics, Journal of the Royal Astronomical Society of Canada, Journal of the Barbados Astronomical Society, Meudon Solar Flare Proceedings (Meudon, France)

Education/Credentials
B.A. degree in Astronomy; M.Phil. degree in Physics - specializing in solar physics.

Awards and Honors
Postgraduate research award- Barbados government; Studentship Award in Solar Physics - American Astronomical Society

You are here: Experts > Science > Physics > Astrophysics > astrophysics/ black hole theory

Astrophysics - astrophysics/ black hole theory

Expert: Philip A. Stahl - 10/31/2009

Question
I am really in need of help on a theory I am coming up with. I have found most of my answers that would support it, but no one can seem to answer the absolute vital one ( high school doesn't really go in-depth on astrophysics, Steven Hawkings,etc.). I would appreciate any and all help I receive.

In order to prove my theory, I need to know the weight of a star, what metals are made up in it, and if there would be enough metal to be attracted to a rather large electromagnetic field that would cause the star to constantly circle at about 300,000 mph for a period of time. And if the metal needed to act upon the above situation would be too heavy for the star to sustain a stable Femi Pressure, and therein would collapse in on itself. Maybe there is an unidentifiable metal that is lightweight but is highly magnetized and could balance out the Femi Pressure...?
Thank you for any questions you are able to answer!

Answer
Hello,

There are several problems with your theory.

Let's look at it from the aspect of stellar composition first. The fractional elemental abundances for a given star (of undetermined mass) can be represented by:

X + Y + Z = 1

where X = hydrogen fraction (e.g. 0.9), Y = helium fraction, and Z = metallic fraction. After assignment of relative atomic weights, electrons, one obtains (for the mean molecular weight, u, of the star):

u = 1/ [2X + 3Y/4 + Z/2]

about the largest non-specific electromagnetic fields in space (B~ 0.0001T, E ~ 0.1 V/m) are associated with certain solar winds displaced from highly magnetic stars (these include: Ap stars, magnetic cataclysmic binaries, and magnetars).

Let therefore, a free EM field of the magnitudes assumed by about 1 pc from your model star. You would need essentially a metal fractional abundance of near unity to make it work - even then it may not be enough and the distance might have to be reduced significantly (which makes the problem or theory basis, even more contrived and artificial)

Anyway, for the sake of argument, let Z = 1, and then X = 0 (e.g. no H at all) and Y = 0 (no He at all), then the mean molecular weight:

u = 1/ [Z/2] = 1/ [1/2] = 2

the electron molecular weight is meanwhile: u(e) = 2 / 1 + X = 2

In other words, the object is *totally degenerate* as the mean molecular weight is all provided by the electron molecular weight. Needless to say, what you'd have is a "neutronium" style colapsar long before you get to any attraction phase. Thus, the very prerequisite for the attraction (essentially all metallic star) is what destroys the basis of your theory.

Second, it is implausible that even *if* the attraction was adequate (it isn't - see footnote) it could not cause a 10- 15M(s) (M(s) = solar masses) star to rotate at 300,000 mph (133,300 m/s)

Needless to say any such star would be torn asunder by centrifugal force long before it mananged even one period.

--
Footnote: Consider the electric field acting on an electron for the model star at equilibrium (e.g. the force acting on it directed radially inward, e.g. F= mv^2/r equals the force acting on it directed outwards, ewrB). The potential V from the center to the outermost periphery is quanitified by:

V = - w B(d)^2/ 2

Let B, E have the values assumed earlier

we want to find the angular velocity, w and thence frequency needed, and assume d = 2 x 10^9 m

w = -(2V)/ B(d)^2

w ~ 4.5 x 10^-16 rad/s = 2 pi f

The frequency, f:

f ~ (4.5 x 10^-16 rad/s)/ 2 pi = 7.1 x 10^-17 s

or orders of magnitude faster than the most rapidly spinning pulsars.

Hope this helps. If you have further questions feel free to ask. (In particular, please feel free to specify yourself the radius of the star if you don't like my assumed value. Or, you can use the basis here to work out the new frequency yourself!)

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