Faster than a speeding photon

Nice article that explains the theory and concepts behind experiments that makes light travel than the speed of light. Can we receive data before its being sent? What happens to the theory of relativity in that case? Does it fail? Read the article and make your own conclusion

From the article:

The textbooks say nothing can travel faster than light, not even light itself. New experiments show that this is no longer true, raising questions about the maximum speed at which we can send information.

Can a light pulse travel faster than the speed of light? This question has intrigued physicists for many years because such an event could violate Einstein's theory of special relativity and the principle of causality (that 'cause' always precedes 'effect'). Together these imply that no object or information can travel faster than the speed of light, c=310⁸ m s^-1. For nearly two decades, physicists have been sending certain light pulses faster than c over short distances (so-called superluminal propagation), but the light pulses have always been distorted in the process so interpreting these experiments has been difficult.

In May this year, Mugnai et al. reported superluminal behaviour in the propagation of microwaves (centimetre wavelengths) over much longer distances (tens of centimetres) at a speed 7% faster than c. A report by Wang et al. ( page 277 of this issue) now demonstrates a very large superluminal effect for pulses of visible light, in which a pulse propagates in a specially prepared medium with a negative velocity of -c/310: that is, not only faster than a pulse travelling in a vacuum, but so fast that the peak of the pulse exits the medium before it enters it!