I was talking with a guy at work about relativity. I have VERY limited knowledge in the area of physics ( one college level class on radiation physics, and read a few books and essays on my own) but he has absolutely none. He watched a show on Nova or Discovery that blew his mind about light speed and time travel etc. I was explaining to him a little bit about some things I had read when this OTHER guy comes up a starts pontificating a little bit. He's kind of a know-it-all jerk who likes to show off. Granted he has more education than the rest of us (degree in engineering of some sort), but he always tries to lord himself over everyone else. No one was arguing with him, he just started volunteering a bunch of information to everyone. He said one thing that caught my interest and I want to know if it is correct. It sounds like it probably is but I just want to make sure. I am not looking to prove him wrong, just verify what he said. He said that there is still friction in space due to small particles floating around (dust?) and also miniscule amounts of gas like hydrogen and helium. He said that those elements however are so very little like 1 atom per cubit meter, that they don't really have an effect on objects (spacecraft). But he said that as you approach the speed of light, they DO start to have an effect because now said object is traveling through MUCH more area than it was a slower speeds, so the amount of hydrogen, helium, and dust affecting the object is now a factor. A direct relationship between speed and the amount of friction being created. Is that true? This is my first post so I'm sorry if I went too long or whatever. I have an interest in this stuff, but am only starting to realize it at an adult age. Too bad I didn't care enough when I was in high school, perhaps my whole life would be different.