Universe

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Aurora Borealis occurs when materials from the surface of the Sun collide with the atmosphere of the Earth. Experts make predictions about the occurrence of Aurora Borealis based on events taking place on the Sun and the speed of matter being thrown from the Sun's surface. Aurora Borealis is visible in portions of the Northern Hemisphere, including Canada, Scandinavia, North America, Siberia and Northern Europe.

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  • Who discovered the planet Saturn?

    Q: Who discovered the planet Saturn?

    A: It is impossible to determine who discovered Saturn, as it is one of five planets that are visible without the aid of instruments. Saturn has been widely observed by people for thousands of years, although its unique and complex system of rings are only visible using a telescope.
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  • Do the planets travel around the sun in a path called an orbit?

    Q: Do the planets travel around the sun in a path called an orbit?

    A: Planets travel around the sun in paths called orbits. Each planet has its own orbit around the sun, and one orbit around the sun is called a year. All planets travel in the same direction around the sun.
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  • What is the temperature of a black hole?

    Q: What is the temperature of a black hole?

    A: According to NASA, the temperature of a black hole with the mass of the sun is only one ten-millionth of a degree over absolute zero. Scientists determine this by measuring the temperature of the radiation that comes from a black hole.
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  • What are some facts about the Aurora Borealis?

    Q: What are some facts about the Aurora Borealis?

    A: Aurora Borealis occurs when materials from the surface of the Sun collide with the atmosphere of the Earth. Experts make predictions about the occurrence of Aurora Borealis based on events taking place on the Sun and the speed of matter being thrown from the Sun's surface. Aurora Borealis is visible in portions of the Northern Hemisphere, including Canada, Scandinavia, North America, Siberia and Northern Europe.
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  • Why did people once believe that Earth was the center of the Universe?

    Q: Why did people once believe that Earth was the center of the Universe?

    A: The belief of early astronomers that the Earth was the center of the universe stemmed from limited astronomical tools and geocentric attitudes. The Ptolemaic Model, developed around 100 A.D., presented the Earth-centered solar system in which most early Roman astronomers believed.
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  • Why do some stars appear brighter than others?

    Q: Why do some stars appear brighter than others?

    A: The apparent brightness of a star viewed from Earth varies based both on the type of star and its distance from the planet. The apparent magnitude differs from a star's absolute magnitude, which describes its brightness from a set distance, rather than the varying distances of stars seen from Earth. The lower the apparent magnitude, the brighter the star is as seen from Earth.
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  • What happens after a supernova?

    Q: What happens after a supernova?

    A: Depending on the size of the star before it explodes as a supernova, the core of the star either shrinks back into a tiny neutron star or becomes a black hole. If the star is only a few times bigger than the sun, the core becomes a tiny neutron star. If the star is much bigger than the sun, the chances of it becoming a black hole are much greater.
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  • How many modern constellations are there?

    Q: How many modern constellations are there?

    A: As of 2014, there are 41 modern constellations, which are constellations added to the catalogue after 1600. Four of them, Carina, Puppis, Pyxis and Vela are derived from Argo, a constellation catalogued by Ptolemy.
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  • What color is the universe?

    Q: What color is the universe?

    A: When gazing at the starry night sky, you might imagine that the color of the universe is a dark shade of midnight blue. However, the average color is much brighter than that. When all of the universe’s light is averaged together, the resulting color is a much less mysterious light beige.
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  • Q: What is Galileo Galilei famous for?

    A: Galileo Galilei is famous for his physics-related and astronomy-related observations. He built his own telescope in 1609 and used it to study the cosmos, eventually concluding that Earth’s solar system is heliocentric. Galileo’s theories on motion were later used as the foundation of Isaac Newton’s work.
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  • Q: What does the universe contain?

    A: The universe contain galaxies, stars, black holes, planets, comets and meteors. In short, it holds all matter and energy. It also has a lot of empty space. It has around 80 billion galaxies or many large group of stars. The Sun is just one of the many stars in the universe. There are also many planets orbiting these stars. The size of the universe is still unknown.
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  • Q: What are some world facts?

    A: Observed from space, the United States is the brightest country on the brightest planet in the Solar System because Earth's water makes it the brightest planet and the United States is abundant in artificial lighting, especially at night. Russia is the largest country in the world, Vatican City is the smallest country, and 39 million Vatican Cities could fit inside Russia. In 2011, the global population topped 7 billion people and is expected to reach 10.5 billion by 2050.
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  • Q: How do you explain the nebular theory?

    A: The nebular theory of solar system formation suggests that stars and their planets form out of cooling interstellar clouds of molecular hydrogen. As the cloud contracts, it forms a disc of dense material that forms the star. As it forms, the star throws off material that coalesces into planets.
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  • Q: Is there sound in space?

    A: Sound is unable to travel through truly empty space. The phenomenon known as sound is the perception of alternating waves of compression passing through a medium. Unlike light, which is able to propagate without a medium, sound waves must have a medium, such as air, water or rock, to carry them.
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  • Q: Why can't we see past the cosmological horizon?

    A: It's impossible to look beyond the cosmological horizon because this horizon represents the distance that light has traveled since the big bang. The cosmological horizon exists because the speed of light is constant and all electromagnetic waves travel at the same speed. Therefore, the cosmological horizon holds for visible light as well as for other types of waves, such as radio or microwaves.
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  • Q: What percentage of the universe have scientists been able to map?

    A: Scientists estimate that they have mapped 0.42 percent of the observable night time sky as of 2015, but they have no way of determining what percentage of the entire universe the observable portion comprises. They hope to map 12.5 percent of the observable portion by 2018.
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  • Q: What is the function of the solar plexus?

    A: The solar plexus, or celiac plexus, is a large cluster of nerves that relay messages from the major organs of the abdomen to the brain. These organs, called visceral organs, are important to metabolism and to general life functioning. The solar plexus monitors them and makes sure they are functioning correctly.
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  • Q: How many extrasolar planets have been discovered so far?

    A: About 1,700 extrasolar planets have been discovered so far, including 715 discoveries that were announced in February, 2014 by the National Aeronautical and Space Administration. The newest extrasolar planets were discovered when astronomers examined 305 stars with Kepler, NASA's first extrasolar planet mission. Extrasolar planets, also called exoplanets, are planets that exist outside of the solar system.
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  • Q: Who disproved the Ptolemaic theory of the universe?

    A: Nicolaus Copernicus' 16th-century assertion that the Ptolemaic theory of the solar system was wrong was considered revolutionary. However, his published findings in 1514 weren't widely accepted because his studies were based on naked-eye observations. Galileo Galilei used a telescope to disprove the Earth-centered solar system.
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  • Q: What are the differences between the solar system and the Milky Way Galaxy?

    A: The solar system is a system in the universe that is comprised of the Sun, eight official planets, three dwarf planets and approximately 130 satellites of the planets, according to Nine Planets. Besides these bodies, the solar system also has numerous comets and asteroids, which are smaller. On the other hand, the Milky Way is the galaxy within which the solar system falls.
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  • Q: What is Ptolemy's universe theory?

    A: Greek philosopher Claudius Ptolemy believed that the sun, planets and stars all revolved around the Earth. This belief gave way to the ancient Greek theory of a geocentric or Ptolemaic model of the universe. "Geocentric" refers to the belief that the Earth is the center of the universe.
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