Monday, June 12, 2017

Taurids Meteor Shower May Hide Dangers

       The Taurids meteor shower are the result of debris left behind by Encke's comet and, perhaps, an even larger comet that disintegrated 20,000 to 30,000 years ago. Researchers from the Astronomical Institute of the Czech Academy of Science have been tracking this debris. Already discovered among the debris are two large objects of 650 feet to 900 feet in diameter, found in 2005 and 2015, respectively. However, the Czech scientists "claim they have detected a new branch of debris, one that they suspect holds at least two asteroids between 200 and 300 metres (about 650 and 1,000 feet) in size." However, "[t]he Earth only passes through this potentially dangerous branch once every few years, causing greater numbers of shooting stars." Earth will pass through the dangerous branch in 2022, 2025, 2032 and 2039.

       In related news, NASA has released results from its Near-Earth Orbit Wide-field Infrared Survey Explorer (NEOWISE) orbiting telescope, which included 10 new near-Earth objects that NASA believe are large enough to pose a threat. The article states:
       PHAs are classified as asteroids that have a minimum orbit intersection distance of 0.05 astronomical units (1 AU is the distance from Earth to the Sun, so 0.05 AU is about 7.5 million kilometres, or 4.6 million miles). 

       They also must be big enough to have an absolute magnitude of 22 or brighter, which would make them bigger than 140 metres (around 500 feet) in size, assuming they were reflective enough. 

       So far, we know of 1,806 of these objects, and while some will give us a close shave in coming years, none seem to be destined for our backyard.

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