From my son Nick, a splendid young man, restless Internet spelunker, and the prop of my dotage, comes a link to what looks like an worthwhile website: The Worlds of David Darling. I’d never heard of the fellow, but according to Wikipedia he is a well-known British astronomer who has written scads of books.
Anyway, his site is glossy and professional, and the premier attraction therein is a promising resource called The Internet Encyclopedia of Science. Do have a look.