Build a world or a universe.

-- Gamers do it all the time. How hard can it be? Here is an excellent treatise by writer Steven Swiniarski on how to build a world.

-- From the top down:
        Same universal laws? Gravity, electricity and magnetism, nuclear forces.
        Milky Way Galaxy? Position in the galaxy.
        Stellar type? (OBAFGKM) Solar type (G) star? Orbital configuration? Other planetary bodies in system? Moons?
        Planet: Earthlike or not? How different? Geological processes (O.K., "geo" refers to Earth, but I mean volcanism, erosion, etc.), meteorological processes (Storms, rain cycle, air content, air pressure, percentage water covered, cloud covered, etc.), amount of radiation, temperture extremes, etc.
[Note: world-builder must also deal with microbiology, ecology, zoology and botany.]

-- From the bottom up:
        Do you have your aliens and their surroundings set, but don't know how to achieve global consistency? Reverse world-building.What kind of gravity would you need for those ultrathick legs to have developed, or what solar type and atmospheric content is necessary for eyes that scan in the ultraviolet? Screen your other fauna and flora through the same logic filter (if this, then that).

Two ways of adding astronomy:

Integral to plot:  The classic idea story. A story that hinges on the turning of a scientific point can be a thing of beauty, but difficult to craft. It can usually only be achieved in short fiction. Sometimes ideas can be sparked by scanning the latest scientific results in a field (example: NASA news reports that the Martian magnetic field is not centered in the planet like the Earth's, but resides in local nodes scattered over the surface.)

As spice: Adds a deeper (3D) texture to settings. Acts as a psychological trigger (for most people) that prompts a sense of wonder. Like stars add sparkle to a dark sky, bits of astronomy scattered in your writing can enrich and brighten scenes.

The best world-building textbooks:

Aliens and Alien Societies , Stanley Schmidt
World-Building by Stephen Gillett

Also of interest:
Physics of Star Trek by Lawrence Krauss

--Read science fiction written by astronomers and physicists for examples of well-written, accurate, heavy-on-astronomy fiction.

Sir Fred Hoyle
Eric Kotani (Dr. Yoji Kondo - NASA scientist)
Charles Sheffield
Robert Sawyer
Caroline Clink (mostly poetry)
Ben Bova
Robert Forward
Stanley Schmidt
David Brin (UCSD, 1981, Ph.D. Space Physics)
Gregory Benford
Geoffrey Landis (NASA Ames)
Carl Sagan
Marianne Dyson
Mary Soon Lee (her degree is aeronautics)
Catherine Asaro

Fiction from the NASA sites (accurate, but not well-written).
Our Summer Vacation Was Out of This World by Patrick Meyer and Becky Bray (Interactive fiction on NASA site). Beware the dangers in adding science to a story: too much at once, too technical or flat-out boring.This NASA story faults in many ways, plus, it isn't even a story.

Astronomically accurate fiction picks:

·    Juniper, Gentian, and Rosemary by Pamela Dean (1998, Tor Books)
·    Novels by local Pittsburgh writer William H. Keith, Jr ., who is always astronomically correct. 66 books and counting.
·    Bud Sparhawk’s collection, Dancing With Dragons (his Jupiter stories from Analog Magazine)

Anthologies:
·    From Trifolium Books , The Wonder Zone, three original anthologies of SF stories for readers age 9 and up--Stardust (released January 2002), a 96-page Stardust Teacher’s Guide (for Grade 4), Explorer and Orbiter anthologies (coming soon in 2002). Accurate science!
·    Isaac Asimov’s Solar System edited by Gardner Dozois and Sheila Williams (1999, Ace Books NY)
·    Isaac Asimov’s Moons edited by Gardner Dozois and Sheila Williams (1997, Ace Books NY)
·    Packing Fractions and Other Tales of Science & Imagination ed. Julie Czerneda (1999, Trifolium Books Inc .) For children.
·    Year’s Best Science Fiction edited by Gardner Dozois (St. Martin’s Press)
·    Year’s Best SF edited by David Hartwell (Tor Books)
·    Jupiter (ed. Caroline and Frederick Pohl, 1973) (out of print)
·    Universe (ed. Byron Preiss, 1987) (out of print)
·    Planets (ed. Bryon Preiss, 1985) (out of print)