"Sunjammer"

Over breakfast, I make a big decision. Should I continue to reread previously read stories in the third NESFA collection of Poul Anderson's short works or instead return, without further delay, to rereading his future history novel, Starfarers?

It is impossible to read or reread anything by Anderson without learning something. In the second paragraph of "Sunjammer" (NESFA Vol 3, pp. 221-243), we read that the Andromeda galaxy is one and a half million light years away. I thought that it was two million. To settle the matter, I check Wiki, which says two and a half million! Lesson learned: we really do only have approximations for cosmic distances.

In the same paragraph, Earth seen from space is described as "...a cabochon of clear and lovely blue..." and Luna as "...a tarnished pearl beyond." (p. 221)

Two thoughts:

beautiful, well-observed descriptions, as in the phrase that generated the title, A Stone In Heaven (see here);
another to me unfamiliar word.

I will reread the rest of "Sunjammer."