My question is, what is the speed of light relative to? I did some Googling and the answer is everything. But I don't quite understand. If I'm on Earth and the Sun is directly above me, and I have a laser and shoot a beam of light to Earth's pro- and retrograde, it would be moving c for me since it's relative to everything, included me. That will mean that relative for the sun its going at c+ and c- Earth's speed respectively. I'm slightly (really) confused. Can some one please help me understand this? Also, if two objects were moving at each other at (relative to their point of impact) 0.60c, and I were on one of them, then it would be moving 1.2c relative to me which is impossible. P.S., You can see I'm new to all this relativity thing but I want to understand. EDIT: I understand the bus moving and one km/h less than c and I walked in it two km/h I couldn't go faster than c because special relativity makes the bus and everything in it contract relative to the outside (and everything outside to contract relative to the inside). EDIT: I'm trying to read the Wikipedia article on special relativity.