Evening star. [volume] (Washington, D.C.) 1854-1972, 1939-07-02
BY X. S. RICHARDSON.

PASADENA, Callt.. july l tN.A.
Ma Less than year ago young
Douglas Corrigan achieved fame by
doing something the wrong way.
Sixty-two years ago a moon of
Mars was discovered that, Judged
by the same criterion, should be The
most famous object in the whole
heavens For little Phobos, as it is
called, does everything exactly OPP
posite to the way it shouldn't is the
wrong -Corrigan of the skies.
To begin with. a man on Mars
would see Phobos rise in the west
and set in the east In the second
place, he would see it rise three
times in the length of a Marian
day. And third, Phobos is only 300
miles from the surface of Mars. a
lesser distance than many flyers
have made without a stop.
Mars also has another tiny moon
named DEMOS, but it behaves ID a
more sensible manner. The two
satellites got their names of Phobos
and Deimos fear and panic) from
the two dogs that accompanied the
war god, Mars. on his various mill
tary campaigns.
Tiny Heavenly Bodies.
These are two of the tiniest heav-
emily bodies known to astronomers.
Phobos is 10 miles in diameter and
DEMOS only S. Thus they are not
really worlds at all. but hardly more
than mountains, or fragments OF
planet hurting through space. If
in the year 1899 AID. a space ship
on its way to Pluto should have to
make forced landing on Phobos,
the passengers would have a lot of
fun going outside to stretch their
legs. For owing to its small mass,
the force of gravity on Phobos is
about thousand times less than it
Is here.
A man who weighs 200 pounds on
the earth would weigh but 3 ounces
on Phobus. But in spite of his
light weight he would have the
strength of Hercules. For his mus
cular strength would remain the
same. while everything would feel
one-thousandth as heavy as he ex-
poets 1t to- He could pick up
rock and hurl it at Mars so fast it
might never fall back again. Giant
leaps OF a thousand feet would be
nothing. Indeed. he would have to
be careful and not get up too much
speed, for he might fly off and never
return. In which case, he would be
in danger of having to revolve
around Mars in an orbit of his own.
He would have made a satellite out
OF himself, in other words.
AS seen from Phobos, Mars would
be an enormous reddish globe ex-
tending halfway across the sky. Pho
hos is so close that the Marian Polar
snow caps would be hidden by the
curvature of the planet, just as the
top of a house is hidden by the
walls, if you get too close to them.
A Fast Traveller.
Phobos moves with a speed OF
1890 miles per hour, so fast that it
gains lap over a point on Mars
once every II hours. During a part
OF this time, Phobos plunges into
the shadow of Mars and the sun
light is cut of, as if it had entered
a tunnel. But the presence of Mars
could still be dinly discerned by
the mammoth black hole it makes
In the sky, outlined by the brilliant
stars.
DEMOS is 1880 miles from the
surface of Mars and goes around it
only a little slower than Mars ro-
tates on its axis. AS a consequence.
there is an interval of go hours be-
tween the time Deimos rises and
sets. Mars would appear 80 times
larger than our moon as seen from
Demos, not as impressive as from
Phobos, but splendid sight never
theless.
Phobos and DEMOS would not be
worth much to the Martians for
purposes Of illumination. Phobos
would present a disk a third the
size of our moon and only 1 per
cent as bright. while Deimos would