Planet Compare - NASA Solar System Exploration
Oct 21, 2025 · NASA’s real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.
In Depth | Ganymede – NASA Solar System Exploration
Jupiter’s moon Ganymede is proving to be a fascinating world. Not only is it the largest moon in our solar system, bigger than the planet Mercury and the dwarf planet Pluto, but NASA’s …
In Depth | Europa – NASA Solar System Exploration
Europa orbits Jupiter every 3.5 days and is locked by gravity to Jupiter, so the same hemisphere of the moon always faces the planet. Jupiter takes about 4,333 Earth days (or about 12 Earth …
In Depth | Amalthea – NASA Solar System Exploration
Amalthea is the largest within this grouping with a mean radius of about 83.5 ± 2.4 km. Amalthea orbits 181,400 km from its parent planet, Jupiter. Amalthea takes 0.498 Earth days to …
In Depth | Callisto – NASA Solar System Exploration
Jupiter and its moons orbit about 484 million miles (778 million kilometers) from our Sun. It takes the Jovian system—Jupiter and all of its moons—about 12 Earth years to complete one orbit …
Europa By the Numbers – NASA Solar System Exploration
May 16, 2024 · Europa is one of the largest of Jupiter’s more than 90 moons. It's the sixth-closest moon to the planet.
In Depth | Io – NASA Solar System Exploration
Io's orbit, keeping it at more or less a cozy 262,000 miles (422,000 kilometers) from Jupiter, cuts across the planet's powerful magnetic lines of force, thus turning Io into a electric generator. Io …
In Depth | Asteroids – NASA Solar System Exploration
Most of this ancient space rubble can be found orbiting our Sun between Mars and Jupiter within the main asteroid belt. Asteroids range in size from Vesta – the largest at about 329 miles (530 …
If you know how big you want the largest size (LS) in the model to be, then the scale is the ratio of the true larg-est size (TLS, e.g., the distance from the Sun to Pluto) to the size in the model (LS):
In Depth | Titan – NASA Solar System Exploration
Only Jupiter's moon Ganymede is larger, by just 2 percent. Titan is bigger than Earth's moon, and larger than even the planet Mercury. This mammoth moon is the only moon in the solar …