When were AD and BC decided? AD probably started in AD 525 and BC probably started in AD 731. All of these are “probably” because there is no concrete evidence. AD is an abbreviation for anno Domini Nostri Jesu Christi, and means “in the year of our Lord Jesus Christ”. BC stands for Before Christ. […]
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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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Why do geese fly in a V-formation? To aid communication and to fly more efficiently. Geese don’t always migrate, but when they do, they can fly for thousands of kilometers and Canada geese can fly 2,400 km in 24 hours! If they find a good tailwind, they can reach speeds of 110 km/h. You may
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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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What are pork barrel projects? It is when politicians secure public money for projects in their home constituencies in order to get support and be reelected. The projects are usually expensive and usually not necessary. In most countries that have a democratically elected government, it is made up of members that are chosen to represent
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What is price elasticity of demand? It is a measure of how much demand for a product changes depending on its price. An object’s elasticity is how much it can stretch. The elasticity of rubber is obviously higher than that of steel. In economics, the elasticity of a price is how much that price can
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How do flies perceive time? Flies see the world in slow motion, possibly seeing things four times slower than we do. We have probably all tried to swat a fly sitting on a table. You swing your hand towards it, you impact the table and you’re sure you got it, only to see the fly
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What causes turbulence? It happens when an airplane flies through turbulent air (hence the word turbulence) and gets buffeted around. Turbulence can cause a plane to suddenly rise or fall hundreds of meters very quickly. It can also cause a lot of shaking, and it can cause some damage to the plane, but it very
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What is the difference between a herb and a spice? Herbs are the fresh part of the plant and spices are the dried root, stalk, seed, or fruit. Herbs and spices have been used for thousands of years. People have used them to flavor food and as medicines. They are both different from vegetables because
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Are lighthouses still necessary? Yes, they are because technology can fail, and some things don’t show up on maps or with sonar. The Lighthouse Directory lists 24,300 lighthouses on its site. The majority of them are still active. This fact alone is enough to show that they are still necessary. Lighthouses cost money to run
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