Saturn is almost twice as far from the sun as Jupiter, and between nine
and ten times farther than we are. His mean distance from the sun is
eight hundred and eighty-seven million miles; but his distance varies
nearly one hundred million miles between perihelion and aphelion. His
orbit is only a trifle more eccentric than that of Jupiter, but the
variation in miles is so much greater because the orbit is so much
larger.
His average distance from the earth at opposition is seven hundred and
ninety-four million miles, but at the most favorable opposition it may
be fifty million miles nearer than that. At conjunction his average
distance is nine hundred and eighty million miles; but his greatest
possible distance at such times may be as much as one billion miles.
When he is in this situation it takes light a little more than an hour
and a half to pass from him to us. At his nearest we receive light from
him in about an hour and six minutes. At his average distance from the
sun, light requires about an hour and twenty minutes to go from one to
the other.
While Saturn is next to Jupiter in size among the planets, he is not
as large as Jupiter by two-thirds, but his mass is almost three times
greater than that of all the other planets put together except Jupiter.
It is ninety-five times greater than that of the earth. In diameter
Saturn is 72,772 miles; but it is more flattened at the poles than any
other planet, and in consequence there is a difference of nearly seven
thousand miles between its polar and its equatorial diameters.
The density of Saturn is less than that of any other planet, and it is
ten times less than that of the earth. No other planet is less dense
than water; but Saturn would float in water, and is not more dense
than cork. On account of its mass its gravity is greater than that
of the earth by about one-tenth. This is not enough to make a very
interesting difference in the weight of objects on Saturn and on the
earth. The average person weighing one hundred and fifty pounds here
would weigh only one hundred and sixty-five pounds on Saturn. The
numerous penny-in-the-slot weighing-machines vary almost that much.
Saturn has eighty-three times more surface than the earth, and more
than seven hundred and fifty times the earth’s volume.