🚀 go-pugleaf

On Wed, 16 Apr 1997, Joseph B. Slone wrote:

> Chris Wagner wrote:
> > 
> > Let me define rest mass and reletive mass (the two terms you're searching
> > for BTW)
> > 
> > Rest mass is the mass of something in *your frame of reference*.  i.e. I
> > have a block sitting in front of me on a scale.  It is at rest with respect
> > to me.  I can therefore measure its mass, at rest... "rest mass".
> > 
> > Anything moving with respect to me has a reletive mass.  This is because
> > the faster you go the greater your reletive mass (to me).  Your reletive
> > mass (to me) is proportional to your velocity and your rest mass.  As
> > velocity goes to c, reletive mass goes to infinity.  Rest mass does not
> > change. The only way for reletive mass to not go to infinity is if the rest
> > mass is zero. Hence, a photon with zero rest mass has zero reletive mass as
> > well.  For an object with positive rest mass, the reletive mass increases with
> > velocity.  To calculate the gravity created by the moving object you need
> > the reletive mass.  Gravity too is reletive.  So an object moving with
> > respect to you exerts more gravity on you than if you were at rest with
> > respect to that object.  If you caught up with the object, matched velocity
> > with it, the gravitational attraction would decrease because its reletive
> > mass (to you) has decreased.  It now exerts the gravitational attraction
> > of only its rest mass.
> 
> Does this mean that if I manage to get a pebble to very near light
> speed, it will start acting like a rather large gravity well?
> 
> 

IMHO it does and that's why I don't like the statement that mass increases
with speed. Momentum is just not a linear function of velocity, the mass
doesn't change. If it would, what you say would have to be true and what
you say can't be true since this would mean that light (moving at c) would
see all masses infinitely large. This would mean that all masses would
"attract" light with the same strength. This is absurd. Every object would
be a black hole. Correct me if I make a mistake here, but this is how I
see it.

Dries van Oosten

Eat any good books lately?