"Harvard meant a lot in my writing life from the beginning, even though I didnt actually do much composition on the spot."

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A major puzzle for which nobody has an answer is this: is there some size at which the planets change their nature from water-rich planets like Neptune, to rocky planets like the Earth? We have found two planets that are the size of the Earth in radius, but they are very close to their host star, so water on the surface would evaporate away.

— Geoffrey Marcy