Like Jupiter, Saturn’s atmosphere is composed mostly of hydrogen. Wind speeds can reach as high as 1609 km/h (1000 mph) which is just about as fast as a speeding bullet. The highest wind speed ever recorded on Earth during a hurricane was in 1996, during Tropical Cyclone Cynthia when gusts reached 408 km/h (253 mph).
At Saturn’s North Pole there is an extremely cool storm going on. It isn’t circular or rounded like most extreme weather systems, but it is actually shaped like a hexagon. The clearest image of this storm can be seen in a composite that was released last month. Each side of the hexagon is 8,600 miles (13,800 km) long, which is very close to the diameter of Earth.
Though the atmosphere is very thin and cold, there is plenty of heat down towards the surface that can generate some extreme storms. In the northern hemisphere, there is a storm which is 10,000 km across. If that were on Earth, it would be like starting in Los Angeles and traveling due east all the way to Beijing, China.
Toward Saturn’s surface the carbon in the air can be pressed into graphite. Yes, Saturn has pencil lead flying around. Even closer to the core, the carbon is pressed into diamonds. If a human were to travel to Saturn, the diamonds would cut through their body like countless little bullets.
If the sun were as tall as a typical front door, Earth would be the size of a nickel and Uranus would be about as big as a baseball.
Uranus orbits our sun, a star. Uranus is the seventh planet from the sun at a distance of about 2.9 billion km (1.8 billion miles) or 19.19 AU.
One day on Uranus takes about 17 hours (the time it takes for Uranus to rotate or spin once. Uranus makes a complete orbit around the sun (a year in Uranian time) in about 84 Earth years (30,687 Earth days).
Uranus is an ice giant. Most (80 percent or more) of the planet's mass is made up of a hot dense fluid of "icy" materials – water (H2O), methane (CH4). and ammonia (NH3) – above a small rocky core.
Uranus has an atmosphere which is mostly made up of hydrogen (H2) and helium (He), with a small amount of methane (CH4).
Uranus has 27 moons. Uranus' moons are named after characters from the works of William Shakespeare and Alexander Pope.
Uranus has 13 known rings. The inner rings are narrow and dark and the outer rings are brightly colored.
Voyager 2 is the only spacecraft to have visited Uranus.
Uranus cannot support life as we know it.
Fact: Like Venus, Uranus has a retrograde rotation (east to west). Unlike any of the other planets, Uranus rotates on its side, which means it spins horizontally.
Pluto is classified as a dwarf planet and is also a member of a group of objects that orbit in a disc-like zone beyond the orbit of Neptune called the Kuiper Belt. This distant realm is populated with thousands of miniature icy worlds, which formed early in the history of our solar system. These icy, rocky bodies are called Kuiper Belt objects or transneptunian objects.
Pluto is about two-thirds the diameter of Earth's moon and probably has a rocky core surrounded by a mantle of water ice. More exotic ices like methane and nitrogen frost coat its surface. Owing to its size and lower density, Pluto's mass is about one-sixth that of Earth's moon. Pluto is more massive than Ceres -- the dwarf planet that resides in the asteroid belt between Mars and Jupiter -- by a factor of 14.
Pluto's 248-year-long elliptical orbit can take it as far as 49.3 astronomical units (AU) from the sun. (One AU is the mean distance between Earth and the sun: about 93 million miles or 150 million kilometers.) From 1979 to 1999, Pluto was actually closer to the sun than Neptune, and in 1989, Pluto came to within 29.8 AU of the sun, providing rare opportunities to study this small, cold, distant world.
Nearly 4.5 billion kilometers (2.8 billion miles) from the Sun, Neptune orbits the Sun once every 165 years. It is invisible to the naked eye because of its extreme distance from Earth. Interestingly, the highly eccentric orbit of the dwarf planet Pluto brings Pluto inside Neptune's orbit for a 20-year period out of every 248 Earth years. Pluto can never crash into Neptune, though, because for every three laps Neptune takes around the Sun, Pluto makes two. This repeating pattern prevents close approaches of the two bodies.
This dramatic view of the crescents of Neptune and Triton was acquired by Voyager 2 approximately 3 days, 6 and one-half hours after its closest approach to Neptune (north is to the right).
The encounter put the spacecraft on a couse plunging southward at an angle of 48° to the plane of the ecliptic. This direction, combined with the current season of southern summer in the Neptune system, gives this picture its unique geometry.
The spacecraft was at a distance of 4.86 million km (3 million miles) from Neptune when these images were taken so the smallest detail discernible is approximately 90 km (56 miles). Color was produced using images taken through the narrow-angle camera's clear, orange and green filters. Neptune does not appear as blue from this viewpoint because the forward scattering nature of its atmosphere is more important than its absorption of red light at this high phase angle (134°).
The Kuiper Belt and the Oort Cloud are regions of space. The known icy worlds and comets in both regions are much smaller than Earth's moon.
The Kuiper Belt and the Oort Cloud surround our sun, a star. The Kuiper Belt is a doughnut-shaped ring, extending just beyond the orbit of Neptune from about 30 to 55 AU. The Oort Cloud is a spherical shell, occupying space at a distance between five thousand and 100 thousand AU.
Long-period comets (which take more than 200 years to orbit the sun) come from the Oort Cloud. Short-period comets (which take less than 200 years to orbit the Sun) originate in the Kuiper Belt.
There may be are hundreds of thousands of icy bodies larger than 100 km (62 miles) and an estimated trillion or more comets within the Kuiper Belt. The Oort Cloud may contain more than a trillion icy bodies.
Some dwarf planets within the Kuiper Belt have thin atmospheres that collapse when their orbit carries them farthest from the sun.
The Kuiper Belt and the Oort Cloud are regions of space and therefore do not have moons. However, several dwarf planets within the Kuiper Belt have moons.
The Kuiper Belt and the Oort Cloud are regions of space and therefore do not have rings. No objects within these two regions are known to have rings.
The first mission to the Kuiper Belt is New Horizons. New Horizons will reach Pluto in 2015.
These two regions of space are not capable of supporting life as we know it.
Fact: Both the Kuiper Belt and the Oort Cloud are named for the astronomers who predicted their existence during the 1950s: Gerard Kuiper and Jan Oort.
Uranus is the only giant planet whose equator is nearly at right angles to its orbit. A collision with an Earth-sized object may explain the unique tilt. Nearly a twin in size to Neptune, Uranus has more methane in its mainly hydrogen and helium atmosphere than Jupiter or Saturn. Methane gives Uranus its blue tint.Discovered: March 13, 1781 by William Herschel.
Distance from the Sun: About 1.8 billion miles, about 19 times further than the Earth.
Year: About 84 Earth years.
Voyager 2 flew past Uranus in 1986, giving us our first close view of the planet. It is still functioning today as it flies in deep space, more than 10 billion miles from Earth. Voyager 2 and its companion spacecraft, Voyager 1, are returning data on how the influence of our sun wanes as they get further from it, and on the characteristics of space between the stars.