What is the Local Bubble? The Local Bubble is an enormous cavity 1,000 light years across that our solar system is currently traveling through. We might think that space between the stars and planets is completely empty, but it isn’t. Depending on where it is, most of interstellar space has about 0.3 to 0.5 atoms
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What is Olbers’ Paradox? Olbers’ Paradox says that if the universe is infinite, eternal, static, and the same in every direction, the night sky should be completely illuminated and very bright, all the time. The Olbers behind Olbers’ Paradox was a German astronomer called Heinrich Olbers. In 1823, he was thinking about the size of
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Why do all the planets orbit in the same plane? All of the planets orbit in the same plane because they were all formed out of the same spinning cloud of gas, and because any planets that orbited at a different angle would have been less stable and could have been destroyed in collisions. The
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What is the Roche limit? The Roche limit is the minimum distance that one planetary body can approach another planetary body without being torn to pieces. The Roche limit is named after Edouard Roche, the French astronomer who first calculated it in 1848. He came up with his theory while he was studying the rings
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What is a magnetar? A magnetar is a neutron star that is the size of a city but is one of the strongest magnetic objects in the universe. Many planets and stars have a magnetic field. Our Earth has a magnetic field that is produced by the spinning liquid metal in the outer core. The
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How could you build a base on the moon? There are several problems involved with building a moonbase, but the biggest one is how to get all of the materials up there. NASA has just announced that they are going to spend $20 billion to put a base on the moon within the next seven
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How do astronomers find exoplanets? Astronomers find exoplanets by measuring tiny changes in starlight, seeing if a star shifts position in the sky, measuring radial velocity, using gravitational microlensing, and sometimes looking at the planet itself. There are billions of stars in our Milky Way galaxy, and it is likely that a huge number of
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Why is Mercury so difficult to visit? Mercury is difficult to visit because, among other things, it is moving so fast, it is very close to the Sun, and it doesn’t have an atmosphere. Out of all the planets in the solar system, Mercury has been visited the least. So far, Mars is the most
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What is the cosmic microwave background radiation? The cosmic microwave background radiation is the heat leftover from the Big Bang. In the early 20th century, Edwin Hubble proved that the universe was expanding. He looked at the red and blue shift of distant galaxies to prove this. If the source of a wave is heading
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Why did Copernicus decide that the sun was at the center of the solar system? Copernicus decided that the sun was at the center of the solar system because it made the most sense when he observed the motion of the other planets. Nicolaus Copernicus was born in Poland in 1473. He was very well
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