Not necessarily time travel. Thats 1 of the possibilities of faster than light travel, but not a requirement. Relativity and time dilation are the factors you are referring to in your post there, but no idea whats their effect beyond lightspeed.

this thought just hit me when going thru my spm book..trials nxt week T_T

Mass is amount of matter right?

what abt mass of antimatter? isit a negative value?

It's a positive value.

then wat are the main differences between matter and anti-matter?

The difference which is perhaps the most clear one to us would be the antiparticle equivalents have opposite charges (e.g. positron, a positive electron)

what makes the charges so special? how exactly does reaction between matter and anti occur?

Well let's talk in conserved quantities here then.

[Assumption: We work in the centre of mass frame, assume that the source of energy has no spin (related to angular momentum) whatsoever, and no charge]

When matter/antimatter is produced, what we have initially is a shitload of energy packed into a small place, which then manifests itself as a particle antiparticle pair. We know charge is conserved, so if one of the particles has charge, then other particle must have opposite charge. Also, we know momentum is conserved, so they both must have opposing momentum. Also, angular momentum is conserved, so if one particle has some spin, the other must have the opposite spin [Note: quantum spin, not classical spin, they're very very different creatures]

How does the reaction occur? Well, it's a quantum process, which almost automatically makes it very weird. Basically it goes through an intermediatary particle, be it a virtual photon (which interestingly enough, has some 'mass'), or some other particles, which are restricted only by the conservation laws I was describing above. Here's the interesting twist: It goes through all these possible pathways, and not only one of them, weighted by the probability of each possible pathway.

basically they just cancel out each other by releasing energy in the process? just like the conservation of momentum : explosion?

o_O
I thought speed of light is the fastest speed achievable?

Reminds me of Space Balls when Dark Helmet asks the crew to go faster than Light speed.

Space Balls.

This post has been edited by ZeratoS: Oct 16 2009, 12:30 AM

In one of my subjects of study, Communication Systems, when calculating the propagation velocity of the waves traveling in the waveguide, it was calculated to be more than speed of light! o_O

I don't know what it meant, nor how is it possible. :/

what does this have anything to do with anti-matter, may i ask?

Look, the only thing we can say is, strictly speaking, there seems to be some properties of particles during interactions that are conserved before and after the reaction. Does it cancel out? Sure you can put on that interpretation, but it seems that you're trying to put on some cause and effect here, that the things cancel each other out by releasing energy, when we simply do not know the reasons behind why it occurs. The only thing we can say is that it seems that these quantities are conserved, e.g. mass-energy conservation in a particle-antiparticle interaction, charge conserved, momentum conserved, angular momentum conserved, etc...

And as you can see from mass-energy conservation, if the other conserved quantities cancelled each other out by releasing energy in the process, well we would have additional energy released in a channel other than mass-energy conservation which would mean it's violated, doesn't it?

~lynn~ : Depends whether you use the group velocity or phase velocity