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I love it when a question well beyond me comes up and I know someone at AW can probably answer it.
When I was a kid, I learned in school that the planet Mercury, alone of the nine, did not rotate. (Man, I'm old, huh?) Now we know that of the eight, none fails to rotate.
My question is, for Mercury alone to have been thought to be non-rotating, with one side always facing the sun, the other always facing away, there must have been a reason, an observation or a measurement or something which led to that conclusion, now disproved.
So my question: Why did astronomers used to believe that only Mercury did not rotate?
Maryn, remembering a particularly good science fiction story which no longer works if Mercury rotates
When I was a kid, I learned in school that the planet Mercury, alone of the nine, did not rotate. (Man, I'm old, huh?) Now we know that of the eight, none fails to rotate.
My question is, for Mercury alone to have been thought to be non-rotating, with one side always facing the sun, the other always facing away, there must have been a reason, an observation or a measurement or something which led to that conclusion, now disproved.
So my question: Why did astronomers used to believe that only Mercury did not rotate?
Maryn, remembering a particularly good science fiction story which no longer works if Mercury rotates