? asked in 科學及數學天文學及太空 · 1 decade ago

solar system


Information about the solar system...



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  • 1 decade ago
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    The Sun is a star - it is not a planet. It is the only star we see during the daytime. The Sun measures more than a million kilometers across.

    It's center is about 15 million degrees Celsius.

    It is about 75% hydrogen and 25% helium.

    The Sun's energy is produced by nuclear fusion reactions. It generates 386 billion billion megawatts of energy!

    Mercury is a small, rocky planet.

    Scientists think that there may be volcanic activity on Mercury, but they aren’t sure. The temperature on Mercury ranges from 90 K to 700 K. It was once believed that there was no water on Mercury, but this turned out to be false. Recent radar information shows evidence of ice at Mercury's north pole! The ice hasn't melted because it is protected from the Sun's heat by shadows of some craters.

    Venus is a small, rocky planet blanketed in a thick layer of yellowish clouds. These clouds are not made of water. Instead, they are formed from a poison called sulfuric acid. It’s surface is about 400 degrees Celsius, so is too hot for rain to form.

    Earth is a small, rocky planet which supports a variety of life!

    Temperatures at the Earth's center may be as high as 7500 K - That's hotter than the surface of the Sun! The Earth is the densest major body in the solar system. The Earth is 4.5 to 4.6 billion years old, but the oldest known rocks are less than 4 billion years old. The Earth is orbited by one moon.

    Mars is a small, rocky planet which is cold and lifeless.

    Mars has permanent ice caps at both poles made up mostly of solid carbon dioxide. We know this as "dry ice." Very strong winds and vast dust storms sometimes blow through the entire planet for months! Mars has two tiny moons which orbit very close to the surface.

    Jupiter is a giant gas planet which is made up of about 90% hydrogen and 10% helium. Jupiter is so big that you could cram 1,000 Earths inside of it! It is thought that Jupiter's "Great Red Spot" is a storm of swirling gas that has lasted for hundreds of years.

    Jupiter has 16 known moons!

    Saturn is a giant gas planet which is made up of about 75% hydrogen and 25% helium. It's most famous for its thousands of beautiful rings. It's rings are made up mostly of water ice, but they may also include rocky particles with icy coatings. Saturn is made up of materials which are lighter than water. If placed in a big pond, Saturn would float much like an ice cube does in a glass of water. Saturn has 18 known moons - more than any other planet!

    Uranus is a giant gas planet which is made up of mostly rock and various ices. Uranus has 15 known moons. Voyager 2 discovered 10 small moons in addition to the 5 large ones already known.

    Neptune is a giant gas planet which is most likely made up of various "ices" and rock. Neptune has been visited by only one spacecraft, Voyager 2 on Aug 25 1989. Almost everything we know about Neptune comes from this one visit. It has 8 known moons.

    Most of the Moon's surface is covered with a mixture of fine dust and rocky debris .The Moon has no atmosphere. But evidence suggests that there may be water ice in some deep craters near the Moon's south pole. Most rocks on the surface of the Moon seem to be between 4.6 and 3 billion years old. The gravitational forces between the Earth and the Moon cause some interesting effects. The most obvious is our ocean tides.

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