ARTHUR C. CLARKE'S VENUS PRIME: VOLUME 3
Today, we are accustomed to artificial satellites which perform such feats, thus rising in the west and
setting in the east (see Bradbury, supra), but the behavior of Phobos was quite a surprise to late-19th-
century astronomers. It was also a bonus to such writers as Edgar Rice Burroughs; who can forget the
hurtling inner moon illuminating the ancient sea beds of Barsoom?
Alas, Phobos doesn’t hurtle very fast, and you’d have to watch for some time to see that it’s moving at
all. And it’s a miserable source of illumination; not only is its apparent size a fraction of our Moon’s, but
it is one of the darkest objects in the Solar System, reflecting about as much light as a lump of coal.
Indeed, it may be largely made of carbon, and altogether bears a close resemblance to the nucleus of
Halley’s Comet, as revealed by a whole flotilla of space probes in 1987. It’s not much use, therefore,
during the cold Martian nights, to warn travelers of approaching thoats, seeking whom they might
devour.
(The erudite Sprague de Camp once pointed out a very peculiar feature of Barsoomian ecology: the
fauna apparently consisted almost entirely of carnivores. The poor beasts must have suffered from acute
malnutrition.)
In “The Wreck of the Asteroid” (Wonder Stories, 1932), explorers first landed on Phobos and had a lot
of fun bouncing around in its approximately one-thousandth-of-an-Earth gravity. Until one of them
overdid it, achieved escape velocity–and started to fall helpless toward the looming face of Mars . . .
It’s a nice, dramatic situation, which author Lawrence Manning milked for all it was worth. The crew
had to make an emergency take off and race after their careless colleague, hoping to catch up with him
before he made yet another crater on Mars.
I hate to spoil the fun, but that just couldn’t happen. Small though it is (about 20 meters a second,
compared with Earth’s 11,200) not even an Olympic high-jumper could attain the escape velocity of
Phobos–especially when encumbered with a spacesuit. And even if he did, he would be in no danger of
falling onto Mars–because he would still have the whole of Phobos’s eight thousand meters per second
or bital velocity. His trifling muscular contribution would make virtually no difference to that, so he
would continue to move in just the same orbit as Phobos, but displaced by a few kilometers. And after
one revolution, he’d be back where he started.
In The Sands of Mars (1954), I brutally turned Phobos into a minisun (by carefully unspecified
technology) in order to improve the climate of Mars. It now occurs to me that this was a trial run for
blowing up Jupiter in 2010: Odyssey Two.
Soon after the appearance of “Hide and Seek,” another British science fiction writer asked me rather
suspiciously: “Have you ever read C. S. Forester’s short story ‘Brown on Resolution’?”
“No,” I answered, truthfully enough. “I’m afraid I’ve never even read the Hornblower books. What’s it
file:///C|/Documents%20and%20Settings/harry/Bureau...-%20Venus%20Prime%203%20-%20Hide%20and%20Seek.html (4 of 190)23-12-2006 18:58:20