Planetary Fact Sheets
- Extensive physical data describing the planets, satellites, and comets of our solar system, courtesy of NASA's National Space Science Data Center. Potentially useful to designers of science fiction settings and the detail-minded.
- http://nssdc.gsfc.nasa.gov/planetary/planetfact.html

Constructing an SF Universe
- Excellent article by professional, published science fiction author, S. Andrew Swann.
- http://www.sff.net/people/SASwann/text/wb.htm