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 doesn’t moving water freeze? Moving water does freeze, but it takes a lot longer and the temperature has to be lower than for still water. This is because of turbulence and heat transfer. It is difficult to make ice in both moving water and standing water. Water does not change temperature quickly, because it
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Why did Venice become a naval superpower? Venice became a naval superpower because of its position, its shipbuilding industry, and its control of trade between Europe and Asia. When we think of Venice these days, we think of a city floating on stilts in the Venetian Lagoon. We think of tourists reclining in gondolas on
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How do we know Earth has an iron core? Experts think that the Earth has an iron core because of the way seismic waves pass through the Earth, its overall density, the abundance of iron, our magnetic field, and laboratory experiments. Before we begin, scientists do not know with absolute certainty that the Earth has
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What were the Pinkertons? The Pinkertons were a detective agency set up by Allan Pinkerton in 1850. The Pinkerton detective agency started out with fairly noble goals, but it ended up becoming hired muscle for large corporations. In the 20th century, the company shifted more toward private security, and it still exists today as Pinkerton,
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How do planes take off and land on an aircraft carrier? Planes take off on an aircraft carrier by using a catapult, and they land by using a hook. Planes take off from an aircraft carrier by using a high-powered catapult. To fly, an airplane needs to have air move over its wings at a
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Who were Currer, Ellis, and Acton Bell? They were the pseudonyms used by Charlotte, Emily, and Anne Brontë. The Brontë sisters are known for some of the most famous novels in the English language. Charlotte Brontë wrote four novels, the most famous of which is Jane Eyre. Emily Brontë wrote Wuthering Heights. Anne Brontë wrote
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What is tuberculosis? Tuberculosis (TB) is a contagious, airborne bacterial infection caused by Mycobacterium tuberculosis. If you have read any books set in Victorian London, you will have seen character after character die of “consumption.” It killed two of the famous Bronte sisters, as well as two of their other sisters and their brother. In
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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 was the first police force? The first police force that we would recognize as similar to our own was most likely the Metropolitan Police, started by Robert Peel in 1829. It was the first full-time, professional, centrally organized police force for a major city, built around preventive patrols, with paid officers under a standardized
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