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TIL While violets and purples look similar, but violets are a single wavelength and purples are a mix of red and blue or violet wavelengths.

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xV6Eb UPDATE: 11/6/2015 The SETI Institute reports that after observing the star with its Allen Telescope Array for more than two weeks, it has found no clear evidence for a signal in either narrowband transmissions, which might be used as a hailing signal for a society to announce its presence, or broadband signals, which could be "produced by intense microwaves used to propel rockets servicing the megastructure." (By the way, how clever is it that SETI has deduced how we might detect alien rockets in deep space? Pretty cool.) SETI hasn't given up, however. It continues to monitor the star, and scientists hope to use more powerful telescopes in the near future to listen even more closely. In what sounds more like a Star Wars plotline than real life, astronomers have found a randomly dimming star that may be surrounded by an alien-built megastructure that’s harnessing energy to fuel an advanced civilization. Sound far-fetched? It very likely is. But so far, scientists have been unable to explain away the mysterious phenomenon with more mundane explanations, such as mistaken telescope readings or orbiting planetary material blocking the star's light. For years, astrobiologists searching for signs of intelligent extraterrestrial life have been looking for just this kind of light signature as evidence that a tech-savvy alien civilization is building massive structures to capture energy. Alien hunters have hoped that the light blocked by these structures would be a dead giveaway to their location. In this video, NASA Jet Propulsion Laboratory astrobiologist and National Geographic Emerging Explorer Kevin Hand explains why some scientists think the Kepler telescope could be picking up the signature of such an alien structure, with the light signature serving as a possible clue. The next step, Hand says, is to tune in radio telescopes to listen for transmissions coming from such a society. The SETI Institute has started doing just that. Professional astronomers, citizen scientists, and space nerds of all ages could soon hear the first crackling transmissions from life-forms from a far-off solar system. Much more likely, however, we'll find only silence. But while some of us might be disappointed that our science fiction fantasies may yet remain fantasies, the discovery is a great reminder of how many scientific revelations—especially those most revolutionary to our way of understanding—began in much the same way as this current discovery: a hunch, then a search, and then lots of checking and rechecking the evidence. But, above all, the greatest discoveries are fueled by the imaginations of intelligent earthlings who dare to ask what might be out there, awaiting us. One particularly interesting point about the current find: The random dimming that’s been recorded indicates that if this is a spherical structure, it must have holes. Perhaps we are witnessing a megastructure still under construction, with gaps in the framework. Alternately, it could be an old structure, falling apart and abandoned. If it's the latter, where would the aliens have gone? If anyone with a telescope spots a Death Star heading this way, we're pretty sure NASA would love to know.
kvjg TIL that there is an island in the Maroni River on the French Guiana/Suriname border which was formed when a British ship “Edith Cavell” ran aground. The shipwreck is covered in foliage.
Oodee TIL about the Chinese massacre of 1871 when a mob of around 500 White and Hispanic persons entered Old Chinatown in Los Angels and attacked, bullied, robbed, and murdered Chinese residents in cold blood.
4Xr9N TIL how Roald Dahl's name is actually pronounced. 'Roo-ahl', not 'r-ohl-d' or 'r-ahl-d'
0wB5L TIL John Edward Allen, who was hired by Ozzy Osbourne as a "personal dwarf" in 1981-83 and renamed by Ozzy as "Ronnie" to mock Ronnie James Dio, also acted in movies such as Blade Runner. He was hung on stage every night as part of the show. He died of an overdose at the age of 49.