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Venus is covered with dense yellow clouds of sulfuric acid. The pressure at its surface is 90 times higher than that at earth’s surface. DIAMETER = 12,104 KM YEAR LENGTH = 225 DAYS MOON = 0

Uranus is lying on its side in space. As a result, the sun shines directly on each pole once every 84 years. Uranus is freezing cold on its surface, but its center is as hot as the surface of the sun. Uranus is a beautiful bluish green color because its atmosphere contains methane gas. It was the first planet to be discovered with a telescope. Uranus has very thin rings. Unlike the rings of Saturn, the rings of Uranus are dark and do not reflect light. DIAMETER = 51,118 KM YEAR LENGTH = 30,687 DAYS MOONS = 17

At the center of our solar system is a star we call the sun. the sun is only one of billions of stars in the milky way galaxy. Hot gases are constantly released from the sun’s surface. Sometimes these gases explode as dramatic solar flares that can be up to 160,000 kilometers (100,000 miles)long. In 1 second our sun gives off more energy than humans have produced in all of history. Without the sun’s energy, life on earth could not exist. Dark spots, called sunspots, are cooler areas on the sun’s surface. They are often many times larger than earth. Each sunspot lasts about 2weeks. DIAMETER = 1,392,000 KM

Saturn is the least dense planet in the solar system. It would actually float in a glass of water, if you could find a big enough glass. Saturn is a large gaseous planet with beautiful rings. Eight hundred earths would fit inside this giant planet. Saturn, like Jupiter , spins so fast on its axis that it bulges at the equator and flattens at the poles. The incredible rings of Saturn are made of ice particles ranging in size from beads to boulders. Saturn also has more than 20 moons. DIAMETER = 120,000 KM YEAR LENGTH = 10,760 DAYS MOONS = 20

Pluto and its moon, charon, are so close in size that some scientists consider tem to be a double planet. Pluto is the farthest planet. It is 6 million km (3.7 billion miles) from the sun. Pluto is covered with methane ice. Some scientists think that Pluto was once a moon of Neptune. Pluto has a very elliptical. Fro 1979-1999 it was actually closer to the sun than Neptune. Pluto is a rocky and icy planet about the size of earth’s moon. Scientists believe it is 70% rock and 30% ice. DIAMETER = 2,274 KM YEAR LENGTH = 90,780 DAYS MOON = 1

It takes Neptune so long to orbit around the sun that human has not seen one complete revolution since it was discovered. Neptune was predicted to exist by scientists before it was ever sighted because of its effect on Uranus’s orbits. DIAMETER = 49,532 KM YEAR LENGTH = 60,200 DAYS MOON = 8

The moon does not give off its own light. It is bright in our sky because, like a mirror, it reflects light from the sun. We experience a solar eclipse when the moon passes directly between earth and the sun, blocking the sunlight. The moon revolves around earth at the same rate that it spins on its axis. Therefore, the same side of the moon always faces earth. DIAMETER = 3,476 KM YEAR LENGTH = 28 DAYS MOONS = 0

Mercury is covered with craters formed long ago by the impact of large rocks from space. This planet looks very similar to our moon. Mercury is the planet closest to the sun. The temperature on the surface of mercury ranges from -183 degree centigrade (-300 degree Fahrenheit) to 437 degree centigrade (800 degree Fahrenheit). Mercury goes around the sun very quickly. Mercury only takes 88 days to make one trip around the sun. DIAMETER = 4,878 KM YEAR LENGTH = 88 DAYS MOONS = 0

Mars has huge craters and canyons. One canyon on mars is as long as the continental united state and 6.5 kilometers (4 miles) deep. Mars has the highest volcanoes in the solar system. Some are three times higher than Mount Everest. Wind and dust storms on mars can engulf the entire planet in red dust. These storms can last more than 2 week at a time. Mars, the fourth planet from the sun, is half the size of earth. It looks red because it is covered by the deep layer of rusted iron dust. DIAMETER = 6,794 KM YEAR LENGTH = 687 DAYS MOON = 2

Jupiter has a distinctive red spot that is bigger than 2 earths. The red spot is probably an enormous whirlpool of gas that has been spinning for centuries. Jupiter is 1.5 times larger than all the other planets in our solar system put together. With its large number of moons, it is like a solar system within a solar system. Jupiter spins faster on its axis than any other planet. Its day is only 10 earth hours long. Jupiter is a large ball of gas. The clouds on the surface contain swirling patterns of different colored gases. DIAMETER = 142,796 KM YEAR LENGTH = 4,337 DAYS MOON = 16

There are 2 million animals and plant species living on earth. It is believed that 99% of all species that have lived on this planet are now extinct. DIAMETER = 12,756 KM YEAR LENGTH = 365 DAYS MOON = 1