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Astronomy by alyssa

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Astronomy.

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Astronomy by alyssa

  1. 1. By Alyssa Jones Period 6
  2. 2.  The universe is the home to all the galaxies, stars, planets, matter, energy, and other objects. The universe is usually defined as the totality of existence. Observations show that the universe is expanding at a accelerating rate.
  3. 3.  Spiral galaxies are made out of dust and bright stars. Elliptical galaxies are round. Some are small, and some are big. Irregular galaxies have many different shapes. The milky way galaxy contains around one trillion stars. It belongs to a group which contains about thirty galaxies.
  4. 4.  Asteroids are small bodies that never grew large enough to be a planet. Meteoroids are a piece of debris in the solar system. When it reaches the Earth’s atmosphere it becomes a meteor. Meteorites is when a meteoroid survives the impact after reaching the ground.
  5. 5.  Mercury and Venus both have no moons. Mercury is the closest planet to the sun. There are many craters on Mercury. Venus is known as Earth’s twin. Venus has very high pressure and temperature.
  6. 6.  Mars has two moons, named Phobos, and Deimos. Mars is called the red planet because iron oxide gives the weathered rocks a reddish color. Earth has one moon, named Luna. Earth formed about 4.54 billion years ago. It takes Earth 365 Earth days to orbit the sun. On Earth water can be a solid, liquid, or a gas.
  7. 7.  Jupiter has sixty-three moons, the main ones are Io, Europa, Ganymede, and Callisto. Jupiter is the largest planet. It also has active volcanoes on its surface. Saturn has a total of sixty-one moons, the main two are Titan, and Rhea. Saturn has a very complex ring system. The second largest planet is Saturn.
  8. 8.  Uranus has twenty-seven moons, two are Cordelia, and Ophelia. Uranus has thin dark rings. It’s axis of rotation is tilted. Neptune has thirteen moons, one is named Triton. Neptunes rings vary in sizes, and thickness. Sometimes its farther from the sun then, the dwarf planet, Pluto.
  9. 9.  The solar system only has eight planets, but also has four dwarf planets. The solar system goes out as far as about 2 light years. Everything in the solar system orbits in the same direction. The solar system is 4.6 billion years old. Most of the solar system is the sun. A light year is the distance light travels in a year.
  10. 10.  Astronomers used to think that the Earth was the center of the universe. The sun is just one out of 200 billion stars in the milky way galaxy, but all the stars are really far apart and well spread out. Jupiter acts as sort of a vacuum cleaner, and pulls in things such as meteors, and comets. A season on Uranus lasts 22 years. When the moon is directly overhead you way slightly less.

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