whycome 7 hours ago

This is a great review. not just for the book itself, but for the other literature around it.

> Though medieval people wrongly believed the Moon was a planet, they understood that its light came from the Sun, used astrolabes and volvelles to track its movements,

I kinda hate this kind of revisionism though. They didn't "wrongly believe" anything. There was nothing wrong about any belief --it was a explanation for the evidence available. It's what we continue to do. The moon literally fit into their definition of "planet" at the time. It basically grouped all non-star bodies together. (And they are the basis for the 7 day calendar used in much of the world. Moon, Mars, Mercury, Jupiter, Venus, Saturn, Sun.)

We can't retroactively apply our modern definitions to their times.

  • Tor3 7 hours ago

    Indeed - "planet" simply means "wandering star" (as opposed to a fixed, non-moving star). The Earth itself wasn't a planet. Things only changed a bit somewhen after Copernicus.

kesava 8 hours ago

Rebecca Boyle’s Our Moon talks a lot about this. A fascinating read!