Speed of Light as Universal Speed Limit?

[JaKiri]

http://physicsweb.org/article/news/4/7/8/1

if you travel at 1/2 C in one direction and your friend does the same in the opposite' date=' if you look out the window as you pass will it appear that you are traveling at C?[/quote']

 

No.

 

To add speeds together (ALL SPEEDS, it's just at low speeds the ab/c^2 term is extremely close to 0), (a+b)/(1+ab/c^2), where a and b are the speeds of the objects and c is the speed of light (299792458m/s).

[crAckZ]

thank you for that explanation. back when i was in high school i asked my physics teacher that and after flipping through some of his books he just brushed me off.

[MadIce]

Here are the results of several superluminal signal experiments carried out by the University of Köln (Germany):

 

Superluminal Signals & Time Tunneling

 

Below an abstract of one of the papers:

The paper elucidates the physical basis of experimental results on superluminal signal velocity. It will be made plausible that superluminal signals do not violate the principle of causality but they can shorten the luminal vacuum time span between cause and effect. This amazing behaviour is based on the property that any physical signal has a finite duration.