escape velocity question

["William J. Larson" <Bill_Larson@COMPUSERVE.COM>]

A great question Jonathan.  May I put it on my physics final exam (on
Thursday)?
If yes, I would you prefer to have it attributed to you.  Is that OK?

Oh, and also a great answer Ka Chun Yu .

Cheers,
Dr. Wm J. Larson
Geneva


> > I was doing some research on 40 Eridani B (a white dwarf).  I read that
> it has 37,000 times the surface gravity of the Earth.  Since Earth's
> escape velocity is 11.2 kilometers per second, the white dwarf's escape
> velocity should be 414,400 kilometers per second, exceeding the speed of
> light.
>
> Shouldn't this make the star invisible?  Perhaps the data is wrong.  Or
> perhaps the light is just deflected.  I've seen the star myself.  It's at
> 9th magnitude.
>
> Help, please!
>
> Jonathan Wojack
> tlj18@juno.com
<