Relativity it's so relative....
superwoman said:
I think you meant zero mass, not infinite mass. As you approach speed of light, all your mass gets converted to energy.
No, "faster than real-time" means that when I order my song on iTMS today, the song should have appeared on my iPod yesterday. Elementary, really.
On the other hand, it could just mean "buffering"....
Actually neither thing happens. This is how it works:
The relativistic energy needed to move an object at certain speed is given by
E=(mo c^2) / sqrt(1-v^2/c^2)
mo is called the "rest mass" of the object v is its speed and c is the speed of light. (I'm using ^2 to denoted "squared" and sqrt to mean "square root").
As the spped of the object approaches the speed of light the term v^2/c^2 gets closer to 1, which in turn means that sqrt(1-v^2/c^2) gets closer to zero. As this happens the energy gets bigger and bigger.
To understand this do this mental exercise: suppose (mo c^2)=1, and for certain v sqrt(1-v^2/c^2)=0.1. The energy will be E=1/0.01=10. Lets increase the speed so that sqrt(1-v^2/c^2)=0.01, the energy will be E=1/0.001=100. As you can see, increasing v will increase E.
When v is really close to c (say v=0.99999 c <--- 0.99999 the speed of light), v^2/c^2 = (0.99999)^2=0.99998 which means that sqrt(1-v^2/c^2) =sqrt(1-0.99998)=sqrt(0.00002)=0.00001. That means the energy is E=100000. Eventually v is so close to c that E tends to infinity. It doesn't get there though because when v=c --> sqrt(1-v^2/c^2)=0, and you know what one of the lost commandments (there were 20 instead of 10) says: "Thou shall never divide by zero!"
What does it all mean? Well it means that to move a mass at the speed of light you need an infinite amount of energy !! Which means that nothing, except electromagnetic waves (of which light forms part), can move at (or above) the speed of light.
Now some people write the energy equation as E = m c^2 (Einstein's famous equation), where m = mo / sqrt(1-v^2/c^2). This "mass" changes dramatically as the speed v increases (just as E). When v=c the "mass" m is infinite. Let me point out that this is no the actual rest mass of the object is just a mathematical abstraction. In any case, E = m c^2 only stipulates that energy and mass are part of the same thing it doesn't mean that the mass of the object will be converted to energy at the speed of light.