The Science of the “Christmas Star”

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O star of wonder, star of night,
Star with royal beauty bright,
Westward leading, still proceeding,
Guide us to thy perfect light.

It may be the most famous star in history. But was it real? Mentioned just once in the gospel of Matthew, the “Star of Bethlehem”, or the “Christmas Star”, may have guided three wise men from the East in search of a newborn king. A few words written on a scroll two thousand years ago isn’t much to go on, but astronomers have a few ideas that may explain the apparition of a star near the time of the birth of Jesus.

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Fraunhofer’s Lines and the Discovery of the Sun

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This year– 2014– marks the 200th anniversary of many important events. The last war between nations on North American soil reached a crescendo when the Brits and Canadians burned down the White House in Washington. Louis XVIII was invited to reoccupy the French throne after Napoleon’s exile. And eight people were killed by the London Beer Flood in which a domino effect of ruptured vats released 1.4 million liters of beer into the streets. But an event of more lasting importance occurred in the labs of an astute German optician, Joseph von Fraunhofer, who discovered a series of gaps in the rainbow spectrum of the Sun that gave the first hints of what stars were made of.

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Miss Leavitt’s Stars and the Size of the Universe

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Henrietta Leavitt

Nature does not give up her secrets easily. But sometimes, with great skill and effort, someone makes a truly important discovery and reveals knowledge even the wisest philosophers once believed to be beyond the reach of mankind.

The composition of stars is one example.  In 1835, the French scientist Auguste Comte declared the composition of stars to be an example of knowledge forever beyond human understanding.  Just a few years after Comte’s death, 19th century astronomers carefully measured starlight with spectroscopes and discovered that stars are made of the same material found on Earth… hydrogen and carbon and oxygen, and other common elements.

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The Mule Driver Who Measured the Universe

At One-Minute Astronomer, we always have a soft spot for the “underdog astronomer”.  Someone who overcomes circumstance to make great astronomical discoveries with skill and curiosity and raw enthusiasm.

Today you get a snapshot of Milton Humason, a former mule driver and janitor who rose to work with Edwin Hubble to establish the distance scale of the universe and become one of the best-known American astronomers of the 20th century.

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Caesar’s Comet

caesar_juliusAncient stargazers recorded the appearance of dozens of bright comets.  These visiting “stars”, which appeared out of nowhere and caused widespread terror, were often taken as omens and signs of doom or great change.  So it was a great historical coincidence that one of the brightest comets in recorded history marked a truly traumatic event– the death of one of the most important statesmen in history, Julius Caesar, in 44 B.C.

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