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A colour lithograph from 1877 depicts the Andromedid meteor shower of 1872<\/p>\n
Antiqua Print Gallery\/Alamy<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
A \u201clost\u201d meteor shower may surprise skywatchers this weekend, astronomers have found, with the potential for as many as 200 meteors per hour on 2 December.<\/p>\n
The shower in question is the Andromedids, which is caused by dust and rocks left behind by the comet 3D\/Biela entering Earth\u2019s atmosphere and burning up. In most years the Andromedids barely produce more meteors than you might expect on an average evening of stargazing. But every so often, they kick off.<\/p>\n
Records show that the Andromedids in 1872 and 1885 were particularly spectacular, with more than 1000 meteors in an hour. The last time the shower was active was in 2011, producing about 50 meteors per hour.<\/p>\n
The reason for this inconsistency is the death of comet 3D\/Biela. The comet was first spotted in 1772, and then again in 1852, when it had split into two pieces, and has never been seen again. It seems to have disintegrated, which caused the particularly bright showers in the late 1800s.<\/p>\n
<\/p>\n But there is still a trail left behind by the comet\u2019s original path, which Earth, on occasion, finds itself flying through. This happens rarely because the debris and dust left by the comet are moving, along orbits similar to the comet. \u201cIt takes the meteoroids 6.7 years to orbit the sun,\u201d says Robert Weryk, at the University of Hawai\u02bbi at M\u0101noa. \u201cEarth is rarely in the same place at the same time.\u201d<\/p>\n This year could be one of those times. In a paper in 2012, astronomers from the University of Western Ontario in Canada, including Weryk, simulated the movement of the dust trail. The model predicted we could be in for as many as 200 meteor per hour, peaking on 2 December.<\/p>\n Last year, the astronomers started working on a refined model, and found the new one disagrees with the original prediction of a strong outburst this year. \u201cThe critical factor is the orbital trajectory of the comet in the 1600s\u201d says Paul Wiegert, who led the research. \u201cWe have to extrapolate backwards in time to determine its earlier position, and the effect of forces due to cometary jets is very hard to predict.\u201d<\/p>\n Nevertheless, Wiegert is looking forward to watching for the outburst. \u201cAll our available meteor detections equipment, cameras and radar, is watching in anticipation,\u201d he says.<\/p>\n To watch the meteor shower yourself, you don\u2019t need any equipment. The Andromedids is named after Andromeda, the constellation from which the particularly bright displays in the 1800s appeared to come from. But this year, the meteors are expected to radiate from nearby Cassiopeia.<\/p>\n You don\u2019t have to know how to find Cassiopeia to see the shower, but it is an easy constellation to spot. To find Cassiopeia, no matter where or when you are looking, a good place to start is by facing north \u2013 Cassiopeia won\u2019t be far away. It is a small, distinctive W or M shaped group of five brights stars. The best time to watch meteor showers is usually after midnight, wherever you are.<\/p>\n Topics:<\/p>\n<\/section><\/div>\n