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Re: escape velocity question

Hi John-
I didn't check the numbers, which should have tipped me off that
the question was dull. O.K. Make the question interesting by bumping the
value of g by a few orders of magnitude.
Regards,
Jack
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Try calculating the escape kinetic energy (relativistically) so
you don't get an absurd result.

No relativity required here. Escape velocity is given classically by

v_esc = (2 g R)^(1/2)

For an escape velocity equal to the speed of light with g = 37,000 g_earth
we would find R = 120 million km (the size of a red giant) and
M = 42 million solar masses. A white dwarf has (I think) a radius closer
to that of Earth so the escape velocity would be "only"
37000^(1/2) x 11.2 km/s = 2.2 x 10^6 m/s, less than 1/100 the speed of
light.

John
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A. John Mallinckrodt http://www.csupomona.edu/~ajm
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"I scored the next great triumph for science myself,
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had marveled over that mystery a long time. We had
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