Michael Swanwick's Periodic Table of Science Fiction

Oxygen

15.9994

Oxygen Planets

Of all life-bearing worlds, oxygen planets are the rarest and most

valuable.

Stars, of course, are as common as dirt, and as filthy with life.

Sundwellers as large as Australia and as small as the state of New Jersey

infest the surface of even so common a star as our own. A red giant like

Aldebaran holds so many living creatures on its surface that it's a

wonder any light gets out at all. Most of the leaders and industrialists

of the Known Universe come from red giants.

Next after stars come the gas giants. Ammonia atmospheres, for some

reason, are particularly conducive to intelligent life. Since

ammonia-based life forms are almost universally floaters, lacking even

rudimentary manipulating limbs, they lead lives of the mind. Most of the

philosophers and theologians of the Known Universe come from gas giants.

Third in line are the vacuum planets. Free of the corrosive effects of an

atmosphere, an enormous variety of magnetic, gravitic, and energy-based

civilizations have arisen. These are the artisan races?the merchants,

mechanics, and artists.

Last of all, and most valued, are the oxygen planets, often called the

"Goldilocks worlds" because in order to hold the extensive oceans that

make such atmospheres stable, they must be neither too far from their

suns nor too near, but can only exist at a "just right" distance.

The oxygen planets are valued for their intelligent species. An oxygen

race typically employs tools, shows enormous ingenuity under stress, is

fiercely loyal and yet irrepressibly playful, and is capable of being

taught almost any skill.

They make great pets.