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https://www.youtube.com/watch?feature...&v=90Omh7_I8vI
المصدر
Allthough this blog is mostly about meteorology--the science of the weather--it's worth commenting on the incredible meteor that streaked through the skies of Russia over the Ural Mountains near 9:20 am local time on Friday. The shock waves from the meteor blew out windows, collapsed the walls and ceiling of a zinc factory, and injured over 950 people. According to astronomer Margaret Campbell-Brown of the University of Western Ontario, in an interview with nature.com, today's meteor was 15 meters in diameter and weighed 40 tons, making it the largest one to affect Earth since the 1908 Tunguska meteor in Siberia. The number of injuries reported from today's event is unprecedented in modern human history for a meteor. The meteor appeared less than a day before asteroid 2012 DA14 will make the closest recorded pass of an asteroid to Earth since sky surveys began in the 1990s--about 17,150 miles, which is closer than the orbit of the GOES weather satellites. According to NASA (as posted on spaceweather.com), "the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north." The odds of the largest meteor strike in 100 years occurring on the same day as the closest asteroid approach in 15 years are about 1 in 200 million, assuming these events are not correlated--truly a cosmic coincidence! The root word meteor comes from the Greek meteōros, meaning "high in the air", and the science of meteorology is the study of weather (notably hydrometeors--things like rain and snow and hailstones that fall from the sky.)
Figure 1. In this photo provided by Chelyabinsk.ru, a meteor contrail is seen over Chelyabinsk, Russia on Friday, Feb. 15, 2013. The meteor streaked across the sky of Russia’s Ural Mountains on Friday morning, causing sharp explosions and reportedly injuring at least 950 people, including many hurt by broken glass. (AP Photo/ Chelyabinsk.ru)
Figure 2. In this photo provided by Chelyabinsk.ru, municipal workers repair damaged electric power circuit outside a zinc factory building with about 600 square meters (6000 square feet) of a roof collapsed after a meteorite exploded over in Chelyabinsk region on Friday, Feb. 15, 2013. (AP Photo/ Oleg Kargapolov, Chelyabinsk.ru)
Figure 3. A hole in Chebarkul Lake, Russia claimed to be from meteorite debris from today's meteor. Photo by Chebarkul town head Andrey Orlov.
Video 1. A Russian dashboard camera caught this incredible video of the February 15, 2013 fireball over Russia. In case you were wondering why there are so many Russian dash board camera videos on the Internet, geek.com explains that it's a combination of the bad weather and corruption in the country.
Video 2. The massive shockwave from the the blast hits at about 0:30 into this video, followed by lots of sonic booms. Thanks go to skyepony for posting this in my blog comments.
Links
engadget.com has a compilation of five impressive videos of the event.
rt.news has an excellent collection of still images and videos.
NASA TV will begin streaming live coverage of the fly-by of asteroid 2012 DA14 at 2 pm EST (19:00 UTC.) The asteroid's closest approach to Earth will be at 2:25 pm EST Friday. The half-hour broadcast from NASA's Jet Propulsion Laboratory in Pasadena, CA, will incorporate real-time animation to show the location of the asteroid in relation to Earth, along with live or near real-time views of the asteroid from observatories in Australia, weather permitting.
Jeff Masters
Categories: Atmospheric Phenomena
https://www.youtube.com/watch?feature...&v=90Omh7_I8vI
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