Really Rocket Science

What is that? HFS!! It’s a meteorite!! A 10-ton rock falling from the sky at 20 km/second — that’s 745 miles per hour! Injured 500 people, too.

The Russian Academy of Sciences is referring to it as the “Chelyabinsk Fireball,” weighing 10 tons and with a velocity of up to 20 meters per second.

Сегодня утром в районе города Челябинска было зарегистрировано падение космического тела, вызвавшее яркую световую вспышку и сильную ударную волну.

Сообщается о выбитых стеклах в домах. По нашим оценкам размер тела составлял несколько метров, масса порядка десяти тонн, энергия несколько килотонн. Тело вошло в атмосферу со скоростью 15-20 км/с, разрушилось на высотах 30-50 км, движение фрагментов с большой скоростью вызвало мощное свечение и сильную ударную волну. Основная часть вещества падающего тела испарилась (сгорела), оставшиеся куски затормозились и могли выпасть на землю в виде метеоритов. Обычно суммарная масса найденных метеоритов составляет не больше 1-5% от начальной массы. Основная энергия выделилась на высотах 5-15 км. Тела такого размера падают довольно часто, несколько раз в год, однако обычно сгорают на больших высотах (порядка 30-50 км). Рассматриваемое тело, по-видимому, было очень прочным, возможно железным. Последний раз похожее явление на территории России наблюдалось в 2002 году (Витимский болид). Более точные оценки можно дать после получения всей имеющейся информации.

Wow. Massive. From the AP…

A meteor that scientists estimate weighed 10 tons streaked at supersonic speed over Russia’s Ural Mountains on Friday, setting off blasts that injured some 500 people and frightened countless more.
The Russian Academy of Sciences said in a statement that the meteor over the Chelyabinsk region entered the Earth’s atmosphere at a speed of at least 33,000 mph and shattered about 18-32 miles above ground.
The fall caused explosions that broke glass over a wide area. The Emergency Ministry says more than 500 people sought treatment after the blasts and that 34 of them were hospitalized.

“There was panic. People had no idea what was happening. Everyone was going around to people’s houses to check if they were OK,” said Sergey Hametov, a resident of Chelyabinsk, about 930 miles east of Moscow, the biggest city in the affected region.

“We saw a big burst of light then went outside to see what it was and we heard a really loud thundering sound,” he told The Associated Press by telephone.
Another Chelyabinsk resident, Valya Kazakov, said some elderly women in his neighborhood started crying out that the world was ending.
Some fragments fell in a reservoir outside the town of Cherbakul, the regional governor’s office said, according to the ITAR-Tass news agency. It was not immediately clear if any people were struck by fragments.

The agency also cited military spokesman Yarslavl Roshupkin as saying that a six-meter-wide (20-foot-wide) crater was found in the same area which could be the result of fragments striking the ground.

Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are traveling much faster than the speed of sound. Injuries on the scale reported Friday, however, are extraordinarily rare.
Interior Ministry spokesman Vadim Kolesnikov said that about 600 square meters (6000 square feet) of a roof at a zinc factory had collapsed. There was no immediate clarification of whether the collapse was caused by meteorites or by a shock wave from one of the explosions.

Reports conflicted on what exactly happened in the clear skies. A spokeswoman for the Emergency Ministry, Irina Rossius, told The Associated Press that there was a meteor shower, but another ministry spokeswoman, Elena Smirnikh, was quoted by the Interfax news agency as saying it was a single meteor.

Amateur video broadcast on Russian television showed an object speeding across the sky about 9:20 a.m. local time (0320 GMT), leaving a thick white contrail and an intense flash.

Donald Yeomans, manager of U.S. Near Earth Object Program in California, said he thought the event was probably “an exploding fireball event.”