Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system – more than twice as massive as all the other planets combined. Jupiter's stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. Jupiter’s iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.
Jupiter is surrounded by dozens of moons. Jupiter also has several rings, but unlike the famous rings of Saturn, Jupiter’s rings are very faint and made of dust, not ice.
Jupiter’s environment is probably not conducive to life as we know it. The temperatures, pressures, and materials that characterize this planet are most likely too extreme and volatile for organisms to adapt to.
While planet Jupiter is an unlikely place for living things to take hold, the same is not true of some of its many moons. Europa is one of the likeliest places to find life elsewhere in our solar system. There is evidence of a vast ocean just beneath its icy crust, where life could possibly be supported.
With a radius of 43,440.7 miles (69,911 kilometers), Jupiter is 11 times wider than Earth. If Earth were the size of a nickel, Jupiter would be about as big as a basketball.
From an average distance of 484 million miles (778 million kilometers), Jupiter is 5.2 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes Sunlight 43 minutes to travel from the Sun to Jupiter.
With four large moons and many smaller moons, Jupiter forms a kind of miniature solar system. Jupiter has 80 moons. Fifty-seven moons have been given official names by the International Astronomical Union (IAU). Another 23 moons are awaiting names.
Jupiter's four largest moons – Io, Europa, Ganymede, and Callisto – were first observed by the astronomer Galileo Galilei in 1610 using an early version of the telescope. These four moons are known today as the Galilean satellites, and they're some of the most fascinating destinations in our solar system. Io is the most volcanically active body in the solar system. Ganymede is the largest moon in the solar system (even bigger than the planet Mercury). Callisto’s very few small craters indicate a small degree of current surface activity. A liquid-water ocean with the ingredients for life may lie beneath the frozen crust of Europa, making it a tempting place to explore.

Saturn is the sixth planet from the Sun and the second-largest planet in our solar system. Like fellow gas giant Jupiter, Saturn is a massive ball made mostly of hydrogen and helium. Saturn is not the only planet to have rings, but none are as spectacular or as complex as Saturn's. Saturn also has dozens of moons.
From the jets of water that spray from Saturn's moon Enceladus to the methane lakes on smoggy Titan, the Saturn system is a rich source of scientific discovery and still holds many mysteries.
With a radius of 36,183.7 miles (58,232 kilometers), Saturn is 9 times wider than Earth. If Earth were the size of a nickel, Saturn would be about as big as a volleyball.
From an average distance of 886 million miles (1.4 billion kilometers), Saturn is 9.5 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight 80 minutes to travel from the Sun to Saturn.
Saturn is home to a vast array of intriguing and unique worlds. From the haze-shrouded surface of Titan to crater-riddled Phoebe, each of Saturn's moons tells another piece of the story surrounding the Saturn system. Currently, Saturn has 53 confirmed moons with 29 additional provisional moons awaiting confirmation.
Saturn's rings are thought to be pieces of comets, asteroids, or shattered moons that broke up before they reached the planet, torn apart by Saturn's powerful gravity. They are made of billions of small chunks of ice and rock coated with other materials such as dust. The ring particles mostly range from tiny, dust-sized icy grains to chunks as big as a house. A few particles are as large as mountains. The rings would look mostly white if you looked at them from the cloud tops of Saturn, and interestingly, each ring orbits at a different speed around the planet.
Saturn's ring system extends up to 175,000 miles (282,000 kilometers) from the planet, yet the vertical height is typically about 30 feet (10 meters) in the main rings. Named alphabetically in the order they were discovered, the rings are relatively close to each other, with the exception of a gap measuring 2,920 miles (4,700 kilometers) in width called the Cassini Division that separates Rings A and B. The main rings are A, B, and C. Rings D, E, F, and G are fainter and more recently discovered.
Starting at Saturn and moving outward, there is the D ring, C ring, B ring, Cassini Division, A ring, F ring, G ring, and finally, the E ring. Much farther out, there is the very faint Phoebe ring in the orbit of Saturn's moon Phoebe.

The seventh planet from the Sun with the third largest diameter in our solar system, Uranus is very cold and windy. The ice giant is surrounded by 13 faint rings and 27 small moons as it rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus appear to spin sideways, orbiting the Sun like a rolling ball.
The first planet found with the aid of a telescope, Uranus was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star. It was two years later that the object was universally accepted as a new planet, in part because of observations by astronomer Johann Elert Bode.
With a radius of 15,759.2 miles (25,362 kilometers), Uranus is 4 times wider than Earth. If Earth was the size of a nickel, Uranus would be about as big as a softball.
From an average distance of 1.8 billion miles (2.9 billion kilometers), Uranus is 19.8 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight 2 hours and 40 minutes to travel from the Sun to Uranus.
Uranus has 27 known moons. While most of the satellites orbiting other planets take their names from Greek or Roman mythology, Uranus' moons are unique in being named for characters from the works of William Shakespeare and Alexander Pope.
All of Uranus' inner moons appear to be roughly half water ice and half rock. The composition of the outer moons remains unknown, but they are likely captured asteroids.
Uranus has two sets of rings. The inner system of nine rings consists mostly of narrow, dark grey rings. There are two outer rings: the innermost one is reddish like dusty rings elsewhere in the solar system, and the outer ring is blue like Saturn's E ring.
In order of increasing distance from the planet, the rings are called Zeta, 6, 5, 4, Alpha, Beta, Eta, Gamma, Delta, Lambda, Epsilon, Nu, and Mu. Some of the larger rings are surrounded by belts of fine dust.

Dark, cold, and whipped by supersonic winds, ice giant Neptune is the eighth and most distant planet in our solar system. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye. In 2011 Neptune completed its first 165-year orbit since its discovery in 1846.
Neptune is so far from the Sun that high noon on the big blue planet would seem like dim twilight to us. The warm light we see here on our home planet is roughly 900 times as bright as sunlight on Neptune.
With a radius of 15,299.4 miles (24,622 kilometers), Neptune is about four times wider than Earth. If Earth were the size of a nickel, Neptune would be about as big as a baseball.
From an average distance of 2.8 billion miles (4.5 billion kilometers), Neptune is 30 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight 4 hours to travel from the Sun to Neptune.
Neptune has 14 known moons. Neptune's largest moon Triton was discovered on October 10, 1846, by William Lassell, just 17 days after Johann Gottfried Galle discovered the planet. Since Neptune was named for the Roman god of the sea, its moons are named for various lesser sea gods and nymphs in Greek mythology.
Triton is the only large moon in the solar system that circles its planet in a direction opposite to the planet's rotation (a retrograde orbit), which suggests that it may once have been an independent object that Neptune captured. Triton is extremely cold, with surface temperatures around minus 391 degrees Fahrenheit (minus 235 degrees Celsius). And yet, despite this deep freeze at Triton, Voyager 2 discovered geysers spewing icy material upward more than 5 miles (8 kilometers). Triton's thin atmosphere, also discovered by Voyager, has been detected from Earth several times since, and is growing warmer, but scientists do not yet know why.
Neptune has at least five main rings and four prominent ring arcs that we know of so far. Starting near the planet and moving outward, the main rings are named Galle, Leverrier, Lassell, Arago, and Adams. The rings are thought to be relatively young and short-lived.
Neptune's ring system also has peculiar clumps of dust called arcs. Four prominent arcs named Liberté (Liberty), Egalité (Equality), Fraternité (Fraternity), and Courage are in the outermost ring, Adams. The arcs are strange because the laws of motion would predict that they would spread out evenly rather than stay clumped together. Scientists now think the gravitational effects of Galatea, a moon just inward from the ring, stabilizes these arcs.