Would flashes of light reach Mars?

05 June 2011

Question

Would flashes of light reach Mars?

Answer

Dave - Basically, the answer is yes. You would see it flashing. The only way you wouldn't be able to see it flashing is if somehow the light was getting mixed up between when it was on and when it was off and that would mean that the light getting to you would have to be going through different paths and mixing up. Light goes about 300, 000 kilometres every second, so, if it's 2 seconds on, 2 seconds off, then the different paths the light is travelling must be at least 600,000 kilometres different and then lots of different paths and all mixing up, so it mixes up on and off all the time. The reason why you can see stars burning now even though they might have finished burning already is just that the light has been travelling for longer than the life that the star had left when it emitted the light, so it's travelling 60 million years, a billion years whatever, and the stars have now just died, just in the time it took the light to get to us.

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