9781422283707

or thousands of years stargazers knew of only five planets besides the Earth. They could see these bodies with the naked eye, looking like bright stars wander- ing across the night sky. It was not until 1781 that another planet was spotted, which was named Uranus. The discovery of Uranus set astronomers looking for other new planets, and two more were eventually found— Neptune in 1846 and Pluto in 1930. Uranus and Neptune are large planets, each about four times bigger across than the Earth. And they are quite different from the Earth. Like the giant planets Jupiter and Saturn, they are made up mainly of gas and Int roduct ion F

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