Of space ... and spaciness

The Moon remains the the high-water mark of in-person human exploration. (That may someday change -- thank you, Elon Musk -- but for now, it is what it is.)

Mmmm. Dough ... nut.One of the things I find most fascinating about that too-long-since-visited neighbor is how little we know about it. The debate continues about how the Moon first came to be. While I find the prevailing Theia/Giant-Impact Hypothesis qualitatively plausible -- it's not like I've done the math -- that theory has its share...