Tuesday, February 20, 2007

Things that go "Bang" in the night

The night of February 23rd, 1987 started off as a very typical night for observatories around the world, and it ended up being one of the most important nights for astronomy in the modern era. At the Las Campanas Observatory in Chile, one of the telescope operators, Oscar Duhalde (pictured above), took a break and went out to look up at the sky. At this time of year, the Milky Way's brightest companion galaxy, the Large Magellenic Cloud, is high in the sky. Oscar noticed a star in the LMC that he'd never seen before, but then had ti get back to work. At a neighboring telescope, astronomer Ian Shelton was taking a four-hour long picture of part of the Large Magellenic Cloud. In these days, we used photographic plates instead of electronic cameras to take astronomical images, so at the end of the exposure, Shelton developed the plate and noticed a bright star where none should have been. After talking among themselves and looking up at the sky, the astronomers at Las Campanas realized that they had detected a supernova -- a massive star ending its life in a cataclysmic explosion. Before news of the supernova filtered out, up to half a dozen people had independently "discovered" the supernova. Supernova 1987A, as the event became known, is the closest supernova to be seen since the invention of the telescope. Because the Large Magellenic Cloud is well-studied, astronomers even knew a little bit about the star that exploded. From this event, astronomers have learned a lot, much of it surprising, about the end of stars' lives. Tomorrow I'll talk about a little of what we learned from this supernova.

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