🚀 go-pugleaf

On Thu, 05 Dec 1996 07:53:17 GMT, bhupi...@lightspeed.bc.ca
(Undertaker) wrote:

>Don Dueck <umdu...@CC.UManitoba.CA> wrote:
>
>>> >apparent that, as an object approaches lightspeed, its mass approaches
>>> >infinity.  Doesn't the Law of Conservation of Matter prohibit any gain
>>> >or loss of mass?
>
>>Well, I'm no astrophysicist, but from what I've been taught and actually 
>>understand, an object really gains _matter_ (which is what I think you 
>>are thinking 'mass' means) as it 
>
>I don't think the object gains any matter, otherwise the mass of the
>object would change.  It simply weighs more because the gravitational
>pull generated by the increased speed of the object creates a larger
>gravitational pull by the object on it's surroundings.  This increased
>gravitational pull increases the objects wieght not mass.  Wieght =
>Mass * gravity (9.81 plus or minus .01) on the surface of the earth.
>And decreases as you move away from the surface of the earth.  So if
>you wanted to loose some weight you could simply start living on a
>mountain, or move to the moon when they built a space station out
>there, because the moon's gravity is less than that of the earth.  The
>law of inertia also plays into the appearance of gain of mass.

No, the object actually does gain mass, not just "weight".  Gravity,
or lack thereof, has nothing to with it.  A moving object has kinetic
energy in addition to its rest mass.  The kinetic energy has a mass
equivalent of m=E/c^2.  At every-day speeds, this added mass is
negligible, but at speeds approaching c, the gain in mass is
substantial.  This increase in mass results in a corresponding
increrase in inertia, so further acceleration requires more and more
energy.  The actual formula for relating mass to velocity escapes me
at the moment (the Lorenz Transformation, I think), but it shows that
mass increases to infinity as velocity approaches c.  At exactly c,
the formula is undefined, implying that accelerating any object with a
rest mass to the speed of light is impossible.

>>[...]
>>What makes it so hard to grasp, in my opinion, is that we're so used to 
>>our little view of the universe.  It just seems ludicrous that time 
>>should slow down the faster you go and that you should gain more mass as 
>>well.
>
>Well, actually time doesn't slow down, as you approach speed of light,
>you are sort of passing through time (time traveling into the future).

Sorry, but time does slow down.  Time dilation and length contraction
are two other results of the Lorenz equations.  Think of it this way:
You are in a car at the starting line of an infinitely long race
track.  At the starting line is a clock, and there are markers posted
at exactly one-mile intervals down the track.  As you leave the
starting line and accelerate toward the speed of light, you will see
that the clock will begin to slow down and the mile-markers will begin
to get closer together.  The closer you get to c, the slower the clock
will run and the closer together the mile markers will get.  At
exactly c (forgetting for a moment that the Lorenz equation is
undefined for v=c), the clock would stop completely and the distance
between the mile-markers (and thus the length of the track) would be
zero.

>Theoretically, if you reach lightspeed, the object would then exist
>everywhere at the same time, making it possible to travel to any given
>time period.  (I'me sure this last bit doesn't make much sense, as I
>am not a physicist, but a comp. sci. major).

Well, I'm not a physicist by trade either, but this happens to be a
topic of great interest to me.  As far as I know, everywhere at the
same time doesn't necessarily imply "everywhen" at the same time.  In
fact, at the speed of light, space and time as we know it cease to
exist.  Any kind of time travel probably requires speeds greater than
c, where you get strange things like negative energy and imaginary
mass.

>>I hope I've shed a little light on the subject.  I'd be interested in 
>>further discussion, but perhaps this particular newsgroup isn't the place 
>>for it.
>
>true, this is not the correct place, but I had to make a few
>corrections in your response.

As did I.

-- Tony