A place were I can write...

My simple blog of pictures of travel, friends, activities and the Universe we live in as we go slowly around the Sun.



February 19, 2013

Chelyabinsk, Russia Meteor

New information provided by a worldwide network of sensors has allowed scientists to refine their estimates for the size of the object that entered that atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15).

The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor's airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada. 

"We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "When you have a fireball of this size we would expect a large number of meteorites to reach the surface and in this case there were probably some large ones."

The trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, which hours later made its flyby of Earth, making it a completely unrelated object. The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia.


Preliminary information indicates that a meteor in Chelyabinsk, Russia, is not related to asteroid 2012 DA14, which flew by Earth safely.
The Russia meteor is the largest reported since 1908, when a meteor hit Tunguska, Siberia. The meteor entered the atmosphere at about 40,000 mph (18 kilometers per second). The impact time was 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15), and the energy released by the impact was in the hundreds of kilotons.





Based on the duration of the event, it was a very shallow entry. It was larger than the meteor over Indonesia on Oct. 8, 2009. Measurements are still coming in, and a more precise measure of the energy may be available later. The size of the object before hitting the atmosphere was about 49 feet (15 meters) and had a mass of about 7,000 tons.
The meteor, which was about one-third the diameter of asteroid 2012 DA14, was brighter than the sun. Its trail was visible for about 30 seconds, so it was a grazing impact through the atmosphere.
It is important to note that this estimate is preliminary, and may be revised as more data is obtained.


Scientists have found more than 50 tiny fragments of the meteor, and preliminary tests are turning up information about its contents. However, local residents seem more interested in the black market value of the fragments. As they search for their own pieces of the meteor, sales offers already are filling the Internet, and police are warning all purchasers to prepare for possible fraud.

The meteor – which injured nearly 1,500 people and caused widespread property damage in Chelyabinsk city on Friday. Health officials said 46 of the injured remain hospitalized.

Viktor Grokhovsky, who led the expedition from Urals Federal University, said Monday that 53 fragments of the meteor have been plucked from the ice-covered Chebarkul Lake. He said they are less than a centimeter (half an inch) in size, about 10 percent iron, and belong to the chondrite type, the most common variation of meteorites found on Earth. Friday's meteor left a six-meter-wide (20-foot-wide) hole in the ice covering the lake. Divers inspecting it have found nothing at the bottom, but Grokhovsky said a fragment as large as 50-60 centimeters (20-24 inches) could eventually be found there.

Meanwhile, workers in the city remained busy replacing acres of windows shattered by a powerful shockwave caused by the meteor's strike, the power equivalent to more than 30 Hiroshima bombs. The local governor estimated the damage at 1 billion rubles ($33 million) and said he hopes the federal government will provide at least half that amount.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.