4 ms·
http://en.m.wikipedia.org/wiki/Speed_of_light http://en.m.wikipedia.org/wiki/Speed_of_light Its value is exactly 299,792,458 metres per second because the leng
by resdirector 12y ago
http://en.m.wikipedia.org/wiki/Speed_of_light http://en.m.wikipedia.org/wiki/Speed_of_light
Its value is exactly 299,792,458 metres per second because the length of the metre is defined from this constant and the international standard for time.