Astronomy

A:

There are between 30 and 54 known galaxies in the local group to which the Milky Way belongs. Some astronomers include dwarf galaxies in this number.

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  • What causes day and night to happen?

    Q: What causes day and night to happen?

    A: The Earth goes through a constant cycle of day and night because it rotates on an axis. At any point in time, only about half of the Earth is facing the sun, while the other side is facing away from it. The side that is facing the sun is illuminated (day) while the side facing away from the sun remains dark (night).
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  • What is Jupiter's atmosphere made up of?

    Q: What is Jupiter's atmosphere made up of?

    A: The atmosphere of Jupiter consists of 90 percent hydrogen gas and nearly 10 percent helium. However, its atmosphere has trace amounts of ammonia, sulfur and water vapor. Jupiter is a gas giant that is also the biggest planet in the solar system.
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  • How does gravity keep us on Earth?

    Q: How does gravity keep us on Earth?

    A: Gravity is one of the fundamental forces of the universe, and it keeps us on Earth because it is relentlessly attractive. Every massive particle exhibits gravity by pulling closer to every other particle. The strength of this interaction is dependent on two quantities: the amount of mass and the distance between objects. It is possible to escape Earth's gravity if you have enough energy to speed up sufficiently.
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  • Did Sir Isaac Newton have any children?

    Q: Did Sir Isaac Newton have any children?

    A: Sir Isaac Newton never married and did not have any children. According to Biography.com, the English mathematician and physicist, who was known for his law of gravitation, died on March 31, 1727, at the age of 85.
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  • How many times bigger is the sun than the earth?

    Q: How many times bigger is the sun than the earth?

    A: According to NASA, the sun���s diameter is approximately 100 times larger than the diameter of the earth. The earth would have to be lined up 100 times in order to stretch across the face of the sun.
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  • What is terrestrial navigation?

    Q: What is terrestrial navigation?

    A: Terrestrial navigation is a field of study that helps sea-faring people locate points at sea and on the land. Similarly, it involves being able to identify the position of the ship anywhere in the world. Students are instructed in the use of nautical charts, compass corrections and voyage planning.
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  • How long will the sun last?

    Q: How long will the sun last?

    A: The sun will last approximately another five billion years, according to NASA in 2012. The sun's light and heat are generated by the burning, or fusing, of hydrogen gas into helium gas.
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  • How did Galileo impact the world?

    Q: How did Galileo impact the world?

    A: Galileo's main impact on the world was his improvement upon the telescope and being the first to use it in the science of astronomy. He also supported the Copernican system that stated that planets orbit the sun rather than the Earth as the Catholic Church said at the time. His other contribution was to contradict Aristotle's teachings that heavier objects fall faster than lighter ones.
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  • What causes a lunar eclipse?

    Q: What causes a lunar eclipse?

    A: Lunar eclipses are caused when the moon travels through the Earth’s shadow. Complete lunar eclipses are rare, but partial lunar eclipses may occur up to four times per year.
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  • What are meteorites made of?

    Q: What are meteorites made of?

    A: The meteorites that land on earth can be made of stone, iron or stony iron. A few meteorites are made of volcanic glass, but scientists aren't sure that all of these meteorites are extraterrestrial in nature. They believe some of these meteorites are formed when material from an impact crater liquefies and then turns to glass as it's ejected into the atmosphere.
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  • What is the circle of illumination?

    Q: What is the circle of illumination?

    A: The circle of illumination is the line that separates the Earth to create equal parts of day and night. It passes through the poles and allows the entire Earth to have an equal amount of time spent during the daylight and nighttime hours.
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  • Why do stars pulsate?

    Q: Why do stars pulsate?

    A: Stars appear to pulsate and twinkle in the night sky due to the refraction of light through the Earth's atmosphere. When the light from a star enters the atmosphere, air molecules bounce and deflect the light rays, slightly altering the apparent position and intensity of the star.
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  • Where does the sky end?

    Q: Where does the sky end?

    A: The sky ends at the Karman line, which is located at about 67 miles above sea level. Above this line, space begins. However, technically, the sky does not end so much as the atmosphere, or sky, thins until there is no oxygen left.
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  • How would you describe a solar eclipse?

    Q: How would you describe a solar eclipse?

    A: A solar eclipse occurs when the moon moves directly between the Earth and the sun. The moon's shadow travels over the surface of the Earth and blocks out the light from the sun seen on Earth.
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  • How did the constellation Orion get its name?

    Q: How did the constellation Orion get its name?

    A: Stargazers in ancient Greece observed the "pictures" formed by stars and named the Orion constellation after a mythological hunter. Many origin stories exist, but one popular version recounts Orion's quest to defeat a giant scorpion sent by Gaia, the goddess of Earth, according to the Windows to the Universe.
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  • What does the full moon symbolize?

    Q: What does the full moon symbolize?

    A: The full moon is said to symbolize different things in various cultures, including the control of water as well as the rhythm of time. The phases of the moon are also used to represent phases of life.
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  • What is an elliptical orbit?

    Q: What is an elliptical orbit?

    A: Elliptical orbits are the paths taken by objects as they fly around a massive object, such as the sun or Earth. Such orbits are not round as is commonly supposed; instead, they orbit the massive body in the shape of an ellipse. Ellipses are like circles that have been elongated slightly, and they are also referred to as ovals.
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  • How do I set up a Tasco telescope?

    Q: How do I set up a Tasco telescope?

    A: Tasco provides free online instruction manuals for all of their products. Their telescopes come partially assembled. The tripod needs to be assembled, then the main body of the telescope attached to it. Once the main body of the telescope is on the tripod, the various accessories such as finderscopes and eyepieces need to be attached. The accessories vary slightly by model of telescope.
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  • What is the weather like on Uranus?

    Q: What is the weather like on Uranus?

    A: With an atmospheric temperature of -224 degrees Celsius and a surface temperature of -197 degrees Celsius, Uranus is a very cold planet with strong winds. It is the coldest planet in the solar system.
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  • What is a burnt-out star called?

    Q: What is a burnt-out star called?

    A: A burnt-out star is called a white dwarf. A white dwarf results after a star���s nuclear fuel burns out, which causes it to collapse or implode. While it has a mass similar to that of the sun, its radius is similar to that of the Earth.
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  • How long would it take a passenger plane to fly around the sun?

    Q: How long would it take a passenger plane to fly around the sun?

    A: A passenger airplane, flying at 600 mph, could circle the sun in just over six months. According to Space.com, the sun is a nearly perfect sphere, and there is essentially no difference in circumference at its equator and the circumference from pole to pole.
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