Help Shape the Future of Space Exploration

Join The Planetary Society Now  arrow.png

Join our eNewsletter for updates & action alerts

    Please leave this field empty

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

Juno's first orbit of Jupiter: The

Juno's first orbit of Jupiter: The "Marble Movie"

During its first long orbit of Jupiter, Juno used its JunoCam to capture images of Jupiter and its moons two to four times per hour. From July 10 to July 16, 2016, as Juno receded, it took two frames per hour, with two 7-hour gaps on July 14. From July 16 to July 28, it took four frames per hour, so the animation appears to slow down. From July 29 to August 27, it took two frames per hour. The animation continues until just two hours before Juno's closest approach.

Filed under Jupiter's moons, Io, pretty pictures, Europa, Ganymede, Callisto, many worlds, Juno, animation, Jupiter

Jupiter, Europa, and Io from Junocam

Jupiter, Europa, and Io from Junocam

Juno took this expansive view of Jupiter with two of its moons on August 26, 2016, on approach to its August 27 perijove. Juno was about a million kilometers away from Jupiter at the time. Both moons are farther away from Juno than Jupiter is. Europa is at left, Io at right.

Filed under Jupiter's moons, Io, pretty pictures, Europa, amateur image processing, many worlds, Juno, Jupiter

Jupiter and Io from Junocam

Jupiter and Io from Junocam

Juno captured this view of Jupiter with its innermost large moon Io on approach to its first orbital periapsis, on August 27, 2016. Juno was about 630,000 kilometers from Jupiter at the time.

Filed under Jupiter's moons, Io, pretty pictures, amateur image processing, many worlds, Juno, Jupiter

Items 13 - 15 of 100  Previous12345678910Next

Section Highlights

Planetary Facts

Mass, diameter, density, gravity, orbital characteristics, presented both in metric units and measured relative to Earth.

More »

Asteroids and Comets Visited by Spacecraft

A comparison of all the asteroids and comets ever visited by spacecraft, up to date as of November 10 (when Deep Impact flew past Hartley 2). Vesta is not included.

More »

Every Round Object in the Solar System, to Scale

A correctly scaled, reasonably correctly colored view of the largest bodies in the solar system.

More »

Facebook Twitter Email RSS AddThis

Essential Advocacy

Our Advocacy Program provides each Society member a voice in the process.

Funding is critical. The more we have, the more effective we can be, translating into more missions, more science, and more exploration.



Beyond The Horizon, There's More To Explore!

Become a member of The Planetary Society and together we will create the future of space exploration.

Join Us

Space in Images

Pretty pictures and
awe-inspiring science.

See More

Join The Planetary Society

Let’s explore the cosmos together!

Become a Member

Connect With Us

Facebook, Twitter, YouTube and more…
Continue the conversation with our online community!