"How could he tell the difference?" asked Harry. "When I looked at Planet
Jupiter last night it looked like the stars, only rounder and bigger."
"The planets are so much nearer to us than the stars that we can follow
them as they slowly creep between us and the stars in their journey
around the sun. The stars are so far away that we would have to watch
them for thousands of years before they would seem to move at all, yet
we know they are moving."
"Are the stars moving?" said Harry, in surprise.
"Yes, they are moving, just as distant steamers seen at sea are moving;
but they are so far away that they seem motionless. Don't you remember how
we used to watch them from the seashore. Still they were going as fast
as steam could take them. We might compare the steamers to the stars,
and the little boats nearer shore were more like the planets. We could
easily follow the boats with our eyes as they danced over the waves, and
in the same way we can easily follow the planets as they creep across
the sky, because they are so much nearer to us than the stars."
"The new planet was called Uranus, although at first the friends of
Herschel wanted to name it after him. Next to Uranus comes the planet
Neptune, which was discovered before it was ever seen."