From: utzoo!decvax!harpo!duke!unc!jqw
Newsgroups: net.physics
Title: Equivalence of Mass and Energy
Article-I.D.: unc.3792
Posted: Mon Aug  9 02:56:42 1982
Received: Mon Aug  9 06:23:12 1982


   It has recently been shown (experimentally) that two beams of light
have gravitational attraction for each other.  All forms of energy have
mass and some additionally have rest mass.  The sum of the masses of all
the particles in the fusion reaction are equal before and after (if you
include photons and neutrinos.)

   The center of mass (and of gravity) of a supernova explosion remains
in the same place whether or NOT there are asymmetries. If a greater
mass goes in one direction, it will have a lower velocity and hence
the center of gravity will not move. This is a rather general principle:
if a rocket explodes in flight, the center of gravity of all the pieces
will follow a parabolic path.

   Centrifugal acceleration IS the same thing as gravitational acceleration.
The force is created by the mass of the entire universe that you are rotating
with respect to. If you are the only object in the universe (*ego*), then
when you rotate, there is no force. You also aren't rotating, since there's
nothing to rotate with respect to, but that's the whole point. If there are
only a few, relatively low mass objects in the universe, the centrifugal
force will be small. Linear acceleration is also the same as gravitational
acceleration. You are accelerating with respect to the entire universe (as
represented by your local space-time), and hence the force. The same effect
would be accomplished if every other object in the universe accelerated
in the opposite direction. (Actually, because of the aforementioned
center-of-mass-in-same-place effect, this couldn't really happen.)
If, again, you were in a relatively empty universe, this time positioned
between 2 hundred-foot diameter boulders, you could easily cause a
large acceleration between these rocks with little force, because they would
mass very little.