– 1860
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nYounmay not have heard of him, but in his time French mathematiciannUrbain Le Verrier was famous and respected—at least amongnastronomers. After all, he had just lounged about doing mathematicsnand had discovered an entire planet! A big one, too!
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n(Inn1846, Le Verrier predicted the presence and orbit of Neptune andnpersuaded some astronomers to look for it at the right place. When itnwas found, Le Verrier was given credit for the discovery of Neptune.)
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nMorenthan a decade later, Le Verrier announced that there was an anomalynin Mercury’s orbit—a small difference between what the mathematicalnequations previously laid out by Sir Isaac Newton said Mercury shouldnbe doing in its orbit, and what was actually observed by astronomersnwatching Mercury night after night. Le Verrier said that there couldnseveral explanations for the anomaly—one of which was anothernplanet that was so close to the Sun that it was very difficult tonobserve.
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nOnnthis date in 1860, Le Verrier announced the discovery of such anplanet. He named the planet Vulcan, and he announced it to members ofnthe Académie des Sciencesnwith the words, “Gentlemen, I give you the planet Vulcan!”
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nLenVerrier had once again used mathematics to compute where the newnplanet should be, and he had consulted with amateur astronomer EdmondnModeste Lescarbault, who had apparently spotted the planet in thenright place, making a transit across the face of the Sun.
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| This is a transit of Mercury. |
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n(Wencan sometimes see the planets that are closer to the Sun than Earth,nVenus and Mercury, as they cross the face of the Sun. They look likensmall black dots, and they cross the disk of the Sun in five or sixnhours. These crossings are called “transits.”)
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| This is a sunspot. |
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nThenproblem with this announcement is, Lescarbault was wrong—apparentlynhe was seeing a sunspot seem to move across the Sun as the Sunnrevolved on its axis. And so that made Le Verrier’s announcementnwrong, too. Many astronomers tried to confirm the so-called sightings and failed, and eventually Einstein’s refinement to Newtonian physics explained the anomaly of Mercury’s orbit without the need of another planet.
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Alas!nThere is no planet Vulcan. (Shh! Don’t tell Mr. Spock!)
Alas!nThere is no planet Vulcan. (Shh! Don’t tell Mr. Spock!)n
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nAlsonon this date:
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nEarth at Perihelion
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nScience-fictionnauthor Isaac Asimov’s birthday
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nBerchtold’snDay in Switzerland
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