: : : : : :Since light has no intrinsec mass,it would take an infinite amount of energy to reach its speed (according to Einstein's E=mc²),and your mass would then become infinite.Moreover,if you could go faster than light speed in the vacuum(300 000 km/s) ,you would run time backwards.

: : : : And technically, your mass would be infinite. Therefore, you would be at every point in the universe at the same time.

: : : : Why would time run backwards? If i set my watch to someone else's who's position is stationary, and walked down the street and came back, when i returned the time would still be the same, right? it doesnt matter how fast I run down the street and come back, my watch will stilll be synchronized with the stationary person's. I dont see how time travel can be possible with speed.

: I'm not positive about the time running backwards : idea but I do know that as you increase the : velocity of and object (say an airplane) : and if you synchronize a clock on the ground : with the clock found in the cockpit of the : airplane the clock in the airplane with have run : a little slower than the one on the ground. : So as you increase the speed of a vehicle up to the : speed of light time outside will seem to speed up : and thus time inside will seem to run slower. : Keep in mind the scientists in this experiment : found that the difference of times between the clocks : were only fractions of a second.

: I hope that somehow answers the second part of the question.

Here's an experiment which would prove most useful to this situation:

1) Take two digital watches. Set them both to the same time. It is important to use the exact same brand and type, to be acurate. 2) After a few days, months, etc. of moving, and the other digital watch being stationary, notice the seconds. Are they different? It would also be good if the watch has hundreds of a second. A stop watch would be good for this. I would be really intrigued if someone did this...If the results come back positive, it would be an interest experiment for high school, or college, etc...