Compare the Planets
Comparing the physical characteristics of the worlds in our solar system (and beyond)
The worlds of our solar system come in all shapes, sizes, and colors. Red-eyed Jupiter, ringed Saturn, and frigid Uranus and Neptune are giant gassy globes containing nearly all of the matter in the solar system. These Jovian planets, or gas giants, are huge worlds of air, clouds, and fluid that may have no solid surfaces no matter how deep you go. Everything else in the solar system is just rock, ice, and dust. The largest rockballs are known as the terrestrial planets: Mercury, Venus, Earth, and Mars, with our Moon usually considered part of the club, and now Vesta is applying for membership. Earth is the biggest of all the rocky worlds.
But the planets are not the only worlds of the solar system. All but two of the planets are orbited by moons, each of them a world unto itself. The largest moons are bigger than the smallest planets, and 16 or 17 would qualify as dwarf planets if they orbited the Sun. There are more than 100 Kuiper belt dwarf planets, but only one among the asteroids, Ceres.
Six solid worlds -- Venus, Earth, Mars, Titan, Triton, and Pluto -- have atmospheres dense enough to produce weather. Eris likely does, when it is near its perihelion. We have witnessed active geology on four worlds -- Earth, Io, Enceladus, and Triton -- and we suspect it on Venus, Europa, and Titan. Comparing the same processes across many worlds helps us to understand how each planet's unique composition and history influence its present state, and will help us predict what to expect on Earth in the future.
Pretty Pictures with Many Worlds
These six images document the early assembly of the International Space Station, from 1998 to 2001. Click through for more information on the different stages of assembly.
A montage of 16 of the 17 asteroids and comets that have been photographed up close as of December 2012, when Chang'E 2 flew past Toutatis. This version is in color and shows the bodies at their correct relative (though not absolute) albedo or brightness. Not included is Vesta, which would cover an area about three times the width and height of this montage.
Filed under best of, pretty pictures, many worlds, amateur image processing, scale comparisons, presentation slides, asteroids, comets, near-Earth asteroids, asteroid 21 Lutetia, asteroid 243 Ida and Dactyl, asteroid 25143 Itokawa, asteroid 253 Mathilde, asteroid 2867 Steins, asteroid 433 Eros, asteroid 951 Gaspra, comet Borrelly, comet Halley, comet Hartley 2, comet Tempel 1, comet Wild 2, Chang'E program, Galileo, comet Halley armada, Deep Space 1, NEAR, Deep Impact, Stardust, Hayabusa (MUSES-C), Rosetta and Philae