Say you have a twin, and you go off into space, traveling near the speed of light, when you return, will your twin have aged more? This is called the “Twin Paradox”.The question is this. We have two twin brothers. We send one of them to space, traveling at relativistic speeds (speeds close to the speed of light) who then comes back. Now, special relativity predicts (and it is in fact very well confirmed) the phenomenon called ‘time dilation’, which simply means that a clock in motion relative to an observer seems to run slower than a stationary clock. The fact is traveling twin will be younger than the one on earth. This is a “twin paradox”.
Physicists have verified a key prediction of Albert Einstein’s special theory of relativity with unprecedented accuracy. Experiments at a particle accelerator in Germany confirm that time moves slower for a moving clock than for a stationary one. The paper was published on September 16 in Physical Review Letters. It is the culmination of 15 years of work by an international group of collaborators including Nobel laureate Theodor Hänsch, director of the Max Planck optics institute. The work is the most stringent test yet of this ‘time-dilation’ effect, which Einstein predicted. One of the consequences of this effect is that a person travelling in a high-speed rocket would age more slowly than people back on Earth.
One of the reasons that prevent any object with a mass going at or faster than the speed of light is that the mass is not constant – it increases with velocity and it goes to infinity at the speed of light. So that eventually you need infinite amounts of energy to accelerate infinite mass past the speed of light mark! (and as far as I know we have yet to find an infinite source of energy 🙂