Factgirl's fact of the day:
In Jonathan Swift's 1726 classic, Gulliver's Travels, there is a statement
that Mars had two moons, at a distance of three and a half diameters
from Mars respectively, the nearest one revolving in ten hours and the outermost
in twenty-one and a half hours.
This statement is a remarkable one, because the existence of those
moons was not established until August 1877 by Asaph Hall. Their distance from
Mars, and the length of their orbits also corresponded to Swift's
suggestion. The inner moon is the only known body in the universe that
revolves around a central body faster than the central body rotates -
this fact is also included in Swift's writing.
A few crackpots over the years have attributed this phenomena
to Jonathan Swift being from Mars; More likely he read Galileo's
discovery of the four moons of Jupiter and (wrongly) assumed that each
planet had moons in geometric progression: no moons for Venus, one for
Earth, two for Mars, and Jupiter four.
-it's a fact!