RE: Nuclear Isomer Decay: A Possibility for Breakthrough Space

["Migliore, Charles W" <Charles.W.Migliore@nspco.com>]

I thought gammas had no mass..... how can there be a recoil momentum?

Charles Migliore RRPT

> -----Original Message-----
> From:	Bernard L Cohen [SMTP:blc+@pitt.edu]
> Sent:	Wednesday, March 31, 1999 10:34 AM
> To:	Multiple recipients of list
> Subject:	Re: Nuclear Isomer Decay: A Possibility for Breakthrough
> Space
> 
> 
> On Tue, 30 Mar 1999, Wes Van Pelt wrote:
> 
> > Radsafers,
> > 
> > The below fascinating abstract is about inducing gamma decay as a deep
> space
> > propulsion method.
> > Can anyone explain:
> >     How can isomeric transition be triggered?
> 
> 	-Hitting the nucleus with a gamma ray can excite it to a higher
> energy state which has a short half life
> 
> >     How can the resulting gamma rays be made to go in one direction so
> as to
> > produce propulsion. I thought the direction of gammas must be isotropic.
> 
> 	--Gamma rays going out the back of the space ship propel it
> forward by recoil momentum. Gamma rays forward toward the space ship are
> absorbed by the space ship so they give back to the space ship the
> forward momentum they took from it by recoil in their emission-- they thus
> do not affect the motion of the space ship. 
> 
> 
> Bernard L. Cohen
> Physics Dept.
> University of Pittsburgh
> Pittsburgh, PA 15260
> Tel: (412)624-9245
> Fax: (412)624-9163
> e-mail: blc+@pitt.edu
> 
> 
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