| Planet science page | |||||||||||||||||
| Look at OUR home! |
Earth is the third planet from the sun. As an Earth dweller, you know many facts about this planet. Suppose you have to describe Earth in an article you are writing. Here are some facts you might want to use. Temperatures on Earth range from 58 degrees Celsius to -90 degrees Celsius. About four fifths of Earth's atmosphere is nitrogen gas. The remaining one fifth is mostly oxygen gas. Earth is the only planet with such a large amount of oxygen. Oceans of liquid water cover nearly three quarters of the surface. Clouds of tiny droplets of water or ice crystals hang above Earth's surface. Ice covers the poles. Mountains, valleys, and deep canyons are found on Earth. Active volcanoes are often found near the edges of some land masses. Earth seems to be the only planet that has living things on it. Earth is orbited by one moon, made of rock. The moon orbits Earth every 28 days. The moon's surface has large and small craters, or holes. It is covered with a rocklike dust. | ||||||||||||||||
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We have a total of nine planets in our solar system. Mercury is the closest planet to the sun. Mercury is about the size of Earth's moon. It has hardly any atmosphere at all. Mercury's surface is somewhat like the surface of the Earth's moon, full of craters. The average length of a year on Mercury is 88 days. Venus is the second planet from the sun. In the night sky, Venus is the second brightest object that can be seen from Earth. Venus is about the same as Earth. There is no liquid water on Venus. The average length of year is 224 days. Earth is the third planet from the sun. Temperatures on Earth range from 136 degrees Farenheit to -130 degrees Farenheit. Oceans of liquid water cover nearly three quarters of the surface. The average length of a year on Earth is 365 days. Mars, sometimes called the Red Planet, is the fourth planet from the sun. It is somewhat smaller than Earth. The atmosphere of Mars is thin and consists mainly of carbon dioxide gas. Mars has volcanoes, canyons, craters, and sand dunes. The average length of a year is 687 days. Jupiter, one of the outer planets, is the fifth planet from the sun. It is also the largest planet in the solor system. One well known feature of Jupiter's atmosphere is the Great Red Spot. This region is believed to be a swirling storm in the atmosphere. Like the sun, Jupiter is made mainly of hydrogen and helium. The average length of a year is 11.9 Earth years. Saturn is the sixth planet from the sun. It is the second largest planet in the solar system. The many bright rings that surround the planet are Saturn's most famous feature. These rings are made up of many small, roundish objects. They are thought to be made of ice. The average length of a year on Saturn is 29.5 Earth years. Uranus is the seventh planet from the sun. Uranus has a mass greater than the mass of 14 Earths. It rotates on its side. Like Jupiter and Saturn, Uranus has an atmosphere that is mostly hydrogen with some helium and methane. The average length of a year on Uranus is 84 Earth years. Neptune is the eigth planet from the sun, and the fourth largest planet. Neptune's atmosphere consist of methane. Neptune's atmosphere has a Great Dark Spot. This "spot" is believed to be a huge storm system the size of Earth. It is orbited by eight moons, including Triton, a large pink moon. The average length of a year is 165 Earth years. Pluto is usually the ninth planet from the sun. Pluto is the smallest planet in the solar system. Its mass is about one-sixth that of Earth's moon. Most of Pluto is made of frozen gases. Pluto is the coldest of all the planets. The average length of a year is 249 Earth years. | Check out the other planets! | ||||||||||||||||
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| WOW, this star is HUGE! |
The star that gives us life, is our sun. Nearly nine tenths of the sun is hydrogen gas. About one tenth of the sun is helium gas. There are small amounts of about 80 other substances in the sun. The hot, outer atmosphere of the sun is called the corona. The corona can be seen from Earth only during a total eclipse of the sun. The surface of the sun is in constant motion. Violent motion on the sun's surface may take the form of a solar flare. A solar flare is an eruption on the surface of the sun. A sunspot is a dark region in the atmosphere of the sun. Find a sunspot in the picture. Such a region is cooler than surrounding regions. The number of sunspots increases and decreases during 11-year cycles. Some scientists believe the number of sunspots and the earth's climate are linked. They think that when the number of sunspots increases, Earth is warmer. Although the sun is a star, from Earth it does not look like other stars. The sun appears much larger and brighter. It appears this way because it is much closer to Earth than are other stars. Compared with other stars, the sun is a mid-size star. Compared with Earth, the sun is very large. It would take 109 Earths to fit across the sun's diameter! The sun is 150 million km from Earth. The next closest star is Proxima Centauri. This star is 40 trillion km away! Light moves at a speed of about 300,000 km per secon. It takes 8 minutes for light from the sun to reach Earth. But it takes over four years for light from the next closest star to reach Earth! Just like people, stars pass through a life cycle. Stars are born, grow older, and die. The life cycle of some stars takes billions of years. Some stars have a life cycle of a few hundred million years. The sun is a middle-aged star, at least 4.6 billion years old. Many scientists believe the sun will keep shining for another 5 billion years. | ||||||||||||||||
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