Earth’s Moon
Earth and the Moon are more like a double planet than a planet and a moon. The Moon is quite
Mars’ Moons
Deimos is farther away and moves slowly from east to west. Deimos would look like a small dot of light
Jupiter’s Moons
Io: Fire World Robotic probes may someday provide close-up views of some of the most remarkable vistas in the solar
Saturn’s Moons
Titan: Smog World Surrounded by a thick atmosphere that’s topped by orange smog, and with a landscape that in some
Neptune’s Triton
Triton, the largest satellite of Neptune, orbits in the opposite direction from most moons, suggesting that Neptune captured it in
Pluto
Because it is so far from the Sun, astronomers had a hard time measuring Pluto’s size. They finally got it
Comets
For astronomers, though, a comet’s beauty is not just in its appearance, but in its content: A comet is an
Asteroids
But the next year, astronomers found a second object in a similar orbit, then another, and another. Instead of a
Neptune
After the discovery of Uranus in 1781, astronomers had a difficult time accurately describing the planet's orbit. Uranus seemed to