A Journey in Other Worlds [81]
gravity of 2.14, its smallness having enabled it to
overtake Ganymede in development, notwithstanding the latter's
start. In the face of the evidence before us we must believe
this, or else that, perhaps, as in the case of the asteroid
Hilda, something like a collision has rejuvenated it. This might
account for its size, and for the Nautical Almanac's statement
that there is a 'small and variable' inclination to its orbit,
while Io and Europa revolve exactly in the plane of Jupiter's
equator."
They had about as long a journey before them as they had already
made in going from the earth to Jupiter. The great planet soon
appeared as a huge crescent, since it was between them and the
sun; its moons became as fifth- and sixth-magnitude stars, and in
the evening of the next day Jupiter's disk became invisible to
the unaided eye. Since there were no way stations, in the shape
of planets or asteroids, between Jupiter and Saturn, they kept
the maximum repulsion on Jupiter as long as possible, and moved
at tremendous speed. Saturn was somewhat in advance of Jupiter
in its orbit, so that their course from the earth had been along
two sides of a triangle with an obtuse angle between. During the
next four terrestrial days they sighted several small comets, but
spent most of their time writing out their Jovian experiences.
During the sixth day Saturn's rings, although not as much tilted
as they would be later in the planet's season, presented a most
superb sight, while they spun in the sun's rays. Soon after this
the eight moons became visible, and, while slightly reducing the
Callisto's speed, they crossed the orbits of Iapetus, Hyperion,
and Titan, when they knew they were but seven hundred and fifty
thousand miles from Saturn.
"I am anxious to ascertain," said Cortlandt, "whether the
composition of yonder rings is similar to that of the comet
through which we passed. I am sure they shine with more than
reflected light."
"We have been in the habit," said Ayrault, "of associating heat
with light, but it is obvious there is something far more subtle
about cometary light and that of Saturn's rings, both of which
seem to have their birth in the intense cold of interplanetary
space."
Passing close to Mimas, Saturn's nearest moon, they supplemented
its attraction, after swinging by, by their own strong pull,
bringing their speed down to dead slow as they entered the
outside ring. At distances often of half a mile they found
meteoric masses, sometimes lumps the size of a house, often no
larger than apples, while small particles like grains of sand
moved between them. There were two motions. The ring revolved
about Saturn, and the particles vibrated among themselves,
evidently kept apart by a mutual repulsion, which seemed both to
increase and decrease faster than gravitation; for on approaching
one another they were more strongly repelled than attracted, but
when they separated the repulsion decreased faster than the
attraction, so that after a time divergence ceased, and they
remained at fixed distances.
The Callisto soon became imbued with motion also, but nothing
ever struck it. When any large mass came unusually near, both it
and their car emitted light, and they rapidly separated. The
sunlight was not as strong here as it had been when they entered
the comet, and as they penetrated farther they were better able
to observe the omnipresent luminosity. They were somewhat
puzzled by the approach of certain light-centres, which seemed to
contain nothing but this concentrated brightness. Occasionally
one of these centres would glow very brightly near them, and
simultaneously recede. At such times the Callisto also glowed,
and itself recoiled slightly. At first the travellers could not
account for this, but finally they concluded that the centres
must be meteoric masses consisting entirely of gases, possessing
weight though invisible.
"We have again to face," said Cortlandt, "that singular law that
till recently we did not suppose
overtake Ganymede in development, notwithstanding the latter's
start. In the face of the evidence before us we must believe
this, or else that, perhaps, as in the case of the asteroid
Hilda, something like a collision has rejuvenated it. This might
account for its size, and for the Nautical Almanac's statement
that there is a 'small and variable' inclination to its orbit,
while Io and Europa revolve exactly in the plane of Jupiter's
equator."
They had about as long a journey before them as they had already
made in going from the earth to Jupiter. The great planet soon
appeared as a huge crescent, since it was between them and the
sun; its moons became as fifth- and sixth-magnitude stars, and in
the evening of the next day Jupiter's disk became invisible to
the unaided eye. Since there were no way stations, in the shape
of planets or asteroids, between Jupiter and Saturn, they kept
the maximum repulsion on Jupiter as long as possible, and moved
at tremendous speed. Saturn was somewhat in advance of Jupiter
in its orbit, so that their course from the earth had been along
two sides of a triangle with an obtuse angle between. During the
next four terrestrial days they sighted several small comets, but
spent most of their time writing out their Jovian experiences.
During the sixth day Saturn's rings, although not as much tilted
as they would be later in the planet's season, presented a most
superb sight, while they spun in the sun's rays. Soon after this
the eight moons became visible, and, while slightly reducing the
Callisto's speed, they crossed the orbits of Iapetus, Hyperion,
and Titan, when they knew they were but seven hundred and fifty
thousand miles from Saturn.
"I am anxious to ascertain," said Cortlandt, "whether the
composition of yonder rings is similar to that of the comet
through which we passed. I am sure they shine with more than
reflected light."
"We have been in the habit," said Ayrault, "of associating heat
with light, but it is obvious there is something far more subtle
about cometary light and that of Saturn's rings, both of which
seem to have their birth in the intense cold of interplanetary
space."
Passing close to Mimas, Saturn's nearest moon, they supplemented
its attraction, after swinging by, by their own strong pull,
bringing their speed down to dead slow as they entered the
outside ring. At distances often of half a mile they found
meteoric masses, sometimes lumps the size of a house, often no
larger than apples, while small particles like grains of sand
moved between them. There were two motions. The ring revolved
about Saturn, and the particles vibrated among themselves,
evidently kept apart by a mutual repulsion, which seemed both to
increase and decrease faster than gravitation; for on approaching
one another they were more strongly repelled than attracted, but
when they separated the repulsion decreased faster than the
attraction, so that after a time divergence ceased, and they
remained at fixed distances.
The Callisto soon became imbued with motion also, but nothing
ever struck it. When any large mass came unusually near, both it
and their car emitted light, and they rapidly separated. The
sunlight was not as strong here as it had been when they entered
the comet, and as they penetrated farther they were better able
to observe the omnipresent luminosity. They were somewhat
puzzled by the approach of certain light-centres, which seemed to
contain nothing but this concentrated brightness. Occasionally
one of these centres would glow very brightly near them, and
simultaneously recede. At such times the Callisto also glowed,
and itself recoiled slightly. At first the travellers could not
account for this, but finally they concluded that the centres
must be meteoric masses consisting entirely of gases, possessing
weight though invisible.
"We have again to face," said Cortlandt, "that singular law that
till recently we did not suppose