cheungcheung Posted May 15, 2004 Share Posted May 15, 2004 Einstein had a question when he was 14. That question was "When I fly (in vacuum and without gravity) towards in space with light speed (30km/s), then I take my mirror in front of me, will I see my mirror((in terms of physical words, his face emits light and strike the mirror and then back into his eye))?" After some periods of time, he got the answer, that is yes. Until now , I still don't know why it is possible. Relativity stated that nothing is faster than light, then what makes the lights from his face are fast enough to reach the mirror moving with light speed? I beg experts can help me solve it. Link to comment Share on other sites More sharing options...
YT2095 Posted May 15, 2004 Share Posted May 15, 2004 because he an his mirror are a closed system and not moving rellative to each other, but to an outside observer, things would appear much different sorry if the answer is overly simple, but this isn`t really my area, but at least it`s AN answer Link to comment Share on other sites More sharing options...
jordan Posted May 15, 2004 Share Posted May 15, 2004 I would say that it is becuase light moves at the same speed for every observer, independent of their speed. Therefore, the light reflecting off his face and the mirror would be going 30km/s and he would see his reflection. It wouldn't matter what speed he was moving, he light would always reflect off the mirror and back to him at 30km/s. Link to comment Share on other sites More sharing options...
swansont Posted May 15, 2004 Share Posted May 15, 2004 Einstein had a question when he was 14.That question was "When I fly (in vacuum and without gravity) towards in space with light speed (30km/s)' date=' then I take my mirror in front of me, will I see my mirror(([i']in terms of physical words, his face emits light and strike the mirror and then back into his eye[/i]))?" After some periods of time, he got the answer, that is yes. Until now , I still don't know why it is possible. Relativity stated that nothing is faster than light, then what makes the lights from his face are fast enough to reach the mirror moving with light speed? I beg experts can help me solve it. I think perhaps you meant 30,000 km/s, which is approximately light speed. You couldn't actually travel that fast, but at whatever speed you actually were going, light would still travel at c relative to you - you can't tell that if you are moving or if everything around you is moving, if you're in an inertial frame of reference. As far as you can tell, you are stationary, so there's no problem there. As YT said, the mirror isn't moving relative to you, so that's not an issue. The strange stuff happens for other inertial observers. They see you movong fast, and they also see light travelling at c, but they will see the frequency of that light change, as well as lengths contracted and time running slow for you. A lot of strange things become apparent once you realize that c is invariant. Link to comment Share on other sites More sharing options...
YT2095 Posted May 15, 2004 Share Posted May 15, 2004 I think perhaps you meant 30,000 km/s, which is approximately light speed. 300,000 kms, I think ya missed a 0 Link to comment Share on other sites More sharing options...
Ms. DNA Posted May 15, 2004 Share Posted May 15, 2004 300,000 kms, I think ya missed a 0 300,000 meters/second, not kilometers. Link to comment Share on other sites More sharing options...
blike Posted May 15, 2004 Share Posted May 15, 2004 299,792,458 meters per second. Which is ~300,000 km/s. Link to comment Share on other sites More sharing options...
Ms. DNA Posted May 15, 2004 Share Posted May 15, 2004 Whoops, you're right, blike. I stayed up too late last night, and I don't think I'm awake yet. Link to comment Share on other sites More sharing options...
YT2095 Posted May 15, 2004 Share Posted May 15, 2004 never mind Blike, how `bout ME! ( LOL Link to comment Share on other sites More sharing options...
Ms. DNA Posted May 15, 2004 Share Posted May 15, 2004 OK, YT, if it makes you feel better, you're right too. Link to comment Share on other sites More sharing options...
YT2095 Posted May 15, 2004 Share Posted May 15, 2004 hehehehehe XXX thnx hun, it does coming from you Link to comment Share on other sites More sharing options...
Dave Posted May 15, 2004 Share Posted May 15, 2004 Glad I didn't read this thread before I went into my relativity exam Link to comment Share on other sites More sharing options...
timo Posted May 15, 2004 Share Posted May 15, 2004 While googling around for another post I found this: http://www2.corepower.com:8080/~relfaq/headlights.html If you don´t want to read the text, the short resume of it is: You cannot travel at lightspeed. Link to comment Share on other sites More sharing options...
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