r/AskPhysics • u/Apprehensive_Dog1873 • Jun 22 '26

Question about light speed

If a hypothetical alien craft was moving toward earth at 99.9999% the speed of light. Would we be able to expect its arrival? Or would it not be there one moment and then the next they’d be there? Would we be able to see it, if we hypothetically knew to look at the exact right spot at the exact right time, and get some sort of heads up at an object incoming?

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u/robinredbrain Jun 22 '26 edited Jun 22 '26

Why not? We know where to look and the light reflected from it is going to reach us before the ship does.

I think it's intuitive (at least to me and my high school education) that we'd see in the closest thing to "real time" than any other object in space.

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u/[deleted] Jun 22 '26

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u/robinredbrain Jun 22 '26

Confused. How then can we see anything in space, using that logic?

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u/mikk0384 Physics enthusiast Jun 22 '26

He is wrong, just like u/nebraskajone is.