Martians themselves. Professor Young's estimate is that Phobos may shed
upon Mars one-sixtieth and Deimos one-twelve-hundredth as much reflected
moonlight as our moon sends to the earth. Accordingly, a "moonlit night"
on Mars can have no such charm as we associate with the phrase. But it
is surely a tribute to the power and perfection of our telescopes that
we have been able to discover the existence of objects so minute and
inconspicuous, situated at a distance of many millions of miles, and
half concealed by the glaring light of the planet close around which
they revolve.

If Mars's moons were as massive as our moon is they would raise
tremendous tides upon Mars, and would affect the circulation of water in
the canals, but, in fact, their tidal effects are even more
insignificant than their light-giving powers. But for astronomers on
Mars they would be objects of absorbing interest.

Upon quitting Mars we pass to the second distinctive planetary group of
the solar system, that of the asteroids.




CHAPTER V

THE ASTEROIDS, A FAMILY OF DWARF WORLDS


Beyond Mars, in the broad gap separating the terrestrial from the Jovian
planets, are the asteroids, of which nearly five hundred have been
discovered and designated by individual names or numbers. But any