OUR SOLAR SYSTEM BY REED HURD The Solar System formed around 4.6 billion years ago. The inner planets are smaller and made mostly of rocky and metal. The outer planets are much larger the made mostly of hydrogen, helium and other gases.

THE SUN The sun is a star found at the center of the Solar System. It makes up around 99.86 of the Solar System. At around 1,392,000 kilometer 865,000 miles wide, the Sun’s diameter is about 110 times wider than Earth.

MERCURY The surface of Mercury is very similar to our room. It has a very barren, rocky surface covered with many craters. Mercury has a very low surface gravity. Likewise, there is no air on the surface but it could be trapped underneath.

VENUS The atmosphere of Venus made up mainly of carbon dioxide. Its size is slightly smaller than Earth. It also featured gravity similar to that of Earth.

EARTH It is the only planet that has an atmosphere containing 21 percent oxygen. The Earth is unlike every other planet in the Solar System in a number of different ways. It is the only planet that has liquid water on its surface.

MARS Mars is 141,633,260 miles from the Sun. A year lasts 687 days, almost twice as long as a year on Earth. One day on Mars is 24 hours and 37 minutes, almost the same length as Earth day.

ASTROID BELT Asteroids are chunks of rocks and metal that orbit around the sun. Scientists think that they are loose material that never formed into planets. The main Asteroid Belt is located between Mars and Jupiter. The total mass of all the asteroid is less than of the moon.

JUPITER Jupiter has more than 50 moons. Four of the moons are the size of planets. Europa probably has a liquid ocean beneath its crust.

SATURN Saturn has a small rocky core covered with liquid gas. It is surrounded by a system of rings that stretch out into space for thousands of kilometer. The rings are made up of millions of ice crystals, some as big as houses and other as big as small as specks of dust.

URANUS Uranus was officially discovered by Sir Willian Herschel 1781. … Uranus turns on its axis once every 17 hours, 14 minutes. … Uranus makes one trip around the sun every 84 Earth years. …

NEPTUNE Neptune was named after the Roman god f the sea. … Neptune was first discovered in 1846. … It takes 164.8 Earth years for Neptune to orbit the sun. …

DWARF PLANET PLUTO Pluto named after the Greek god of the underworld. … Pluto has five known moons. … Pluto is the largest dwarf planet. …

BLACK Hole Imagine huge star burning for million of years. Though nuclear fusion , it converts hydrogen to helium. As it ages, through, it slowly runs out of fed.

RESOURCES Harcourt Science Book www.scienceforkids.com www.google.com/images

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