mardi 19 mars 2019

An meteor explosion like ten times Hiroshima goes unnoticed











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March 19, 2019

A stone 10 meters in diameter shook the Earth in an uninhabited region on December 18. Measuring instruments inherited from the cold war indicate this late.

On December 18, 2018, at 11:48 in the morning, 25.6 kilometers above the Bering Sea, a large space rock streaking straight to Earth at 32 kilometers per second exploded upon entering the atmosphere, consuming itself in a gigantic fireball.


Image above: Some color views of the meteor that flew over the North Pacific in December 2018, taken by Japan's Himawari satellite.

Below, only the fish may have witnessed the event. But US military satellites have seen the explosion and the Air Force has informed NASA, which has added the event in its database of fireballs since 1988. The phenomenon was described Monday at a Planetary Science Conference in Houston, Texas.

More than 10 times the Hiroshima explosion

The energy released by the explosion is estimated at 173 kilotons by NASA's Center for Near-Earth Objects. By comparison, the atomic bomb that razed Hiroshima was 15 kt.


Image above: Some color views of the meteor that flew over the North Pacific in December 2018, taken by Japan's Himawari satellite. The meteor is really clear here - bright orange fireball against the blue + white background!

This is the most powerful explosion in the sky since the 440 kt Chelyabinsk, Russia in 2013 that had 1,500 injured by shattered windows including. A meteor is the luminous phenomenon resulting from the entry into the atmosphere of an asteroid or other celestial body. It's a shooting star. If everything does not vaporize in the atmosphere and a piece lands, we speak of meteorite.


Animation above: A animation showing the smoke from the Meteor over the Bering Strait last December, produced using data from JMA_kishou's Himawari satellite. The orange meteor trail in the middle, shadow above-left.

When Simon Proud, meteorologist and satellite data specialist at Oxford University, heard about the meteor by a BBC article on Monday, he had the idea to check the image archive collected by the Japanese weather satellite. Himawari and recorded by his center permanently, he said Tuesday to AFP.

Himawari satellite

Bingo: the satellite was at the right time, in the right place. Simon Proud published the image on Twitter: there is a small fireball above the clouds and the sea.

Ten meters in diameter

Three other civilian satellites, two from NASA (MODIS and VIIRS) and one European (SLSTR), also saw the explosion, according to Proud, but the images are less clear. "It does not surprise me" that such a powerful meteor occurred, soberly reacted Patrick Michel, director of research at the CNRS, the Observatory of the Côte d'Azur, specialist in asteroids.

"It really reminds us that there are lots of things going on above our heads and that it would be good to worry about it," he said. "It reminds us that even though it is the least likely natural risk for us, it is a risk that exists and over the long term it will eventually materialize," he continues.

Near Earth Asteroids. Image Credit: ESA

This rock was about ten meters in diameter. The most important threat concerns objects over 150 meters. "Nothing very unusual," said Rüdiger Jehn, head of the European Space Agency's (ESA) Global Defense Office. "We were lucky that it was over the ocean."

"You have to invest a little money to predict these things," he added. ESA will ask its members for money to create a better protection system at a ministerial meeting in November. "The meteor explosion ensures the perfect promotion of our program, and it's free," he said.

Revisiting the passage of the Cheliabisnk meteorite, in Russia, on February 15, 2013, with a power thirty times greater than the energy released by the atomic bomb of Hiroshima.

Related article:

Russia asteroid impact: ESA update and assessment‏
https://orbiterchspacenews.blogspot.com/2013/02/russia-asteroid-impact-esa-update-and.html

Images, Animation, Text, Credits: AFP/JAXA/Himawari satellite/ESA/Günter Space Page/Orbiter.ch Aerospace/Roland Berga.

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