It's probably not too difficult to use parallax to determine that meteors are atmospheric phenomena (actually to verify, since they had been assumed so, hence their name). (Who first made this measurement?)
However, suppose this measurement, in an alternate universe, revealed that meteors -- the meteor streaks themselves -- were astronomical phenomena, shining from deep space far beyond the atmosphere.
We can roughly estimate the velocity of meteors (in our universe) by modeling a meteor grain as stationary in space and the Earth hitting it at Earth's orbital speed around the sun. Assuming the visual appearance of meteors in the alternate universe is the same as in ours, I think meteors would be determined to be moving faster than the speed of light if they are more than 10000 au = 0.16 light year from the sun. For the purposes of fiction, let's imagine alternate-universe astronomers struggling to explain the observation of no parallax even from widely separated space probes in the solar system observing the same meteor. No parallax despite such a wide baseline implies their distance must be at least ten thousand light years.
Perhaps they are gashes in the fabric of spacetime. But who's on the outside doing the scratching?
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