How thick is the atmosphere? The atmosphere is generally considered to be 10,000 km thick. Our atmosphere is made up of gas. It is 78% nitrogen, 21% oxygen, and one percent other gases. Those other gases are argon, carbon dioxide, helium, neon, methane, krypton, and hydrogen. There is water vapor as well, which is a […]
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What is a nebula? It is an enormous cloud of dust and gas in space. The word nebula is a Latin word, and it means “mist or cloud”. You can see it in the root of the word nebulous. And when we say enormous, most nebula are tens to hundreds of light years across. They
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What is a geosynchronous orbit? It is an orbit that exactly matches the rotation of the Earth. A satellite in geosynchronous orbit goes around the Earth at the same speed the Earth rotates, completing one orbit every 24 hours. From the ground, the satellite appears to be stationary. There are thousands of satellites above us
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Do other planets have tectonic plates? In our Solar System, Earth is the only planet with tectonic plates, but in other solar systems there will probably be planets the same as ours. Out of all the planets in the Solar System, Earth is the only one with tectonic plates. Neptune, Uranus, Saturn, and Jupiter are
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Is a force field possible? In theory, there are several possibilities, such as warping space time, electric fields, directional lasers, a controllable plasma, a magnetic field, and others. We have all seen science fiction movies where a spaceship is protected by a forcefield that destroys enemy fire when it comes into contact. The recent movie
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What is the Fermi paradox? It is the fact that if life in the universe is so common, we should have found signs of it. Enrico Fermi was an Italian physicist. He received a Nobel Prize for physics in 1938 and he was involved with the Manhattan Project in the Second World War. He died
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Watch on YouTube What will happen at the end of the universe? There will either be a Big Crunch, a Big Bounce, a Big Rip, or a Big Freeze. The universe is thought to be 13.7 billion years old. This has been calculated in two ways. The first way is to find the oldest stars
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Watch on YouTube Why is carbon-based life common? Because carbon can bond with many different elements to allow chemical reactions to happen. On our planet all living things contain carbon. There may be lifeforms on other planets that are made of different elements but on Earth, everything uses carbon in one way or another. Plants,
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What is the Great Attractor? It is the theorized gravitational center of our Milky Way Galaxy and 100,000 other galaxies. The universe is expanding at a rate of 2.2 million km per hour. All galaxies should therefore be moving at that speed, but it turns out we are not. Our Milky Way Galaxy is moving
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How long do black holes last? Black holes will slowly dissolve, but it will take far longer than the length of our universe, so it has never been observed. There are two ways that black holes form. The first way is when a star collapses. As stars die, they burn up all of their hydrogen,
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