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---------------------- 2314 - Asteroid hit us on December 18, 2018
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- The asteroid blast was the second largest of its kind in 30 years, and the biggest since the fireball over Chelyabinsk in Russia six years ago.
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- But, it went largely unnoticed until now because it blew up over the Bering Sea, off Russia's Kamchatka Peninsula.
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- This space rock exploded with 10 times the energy released by the Hiroshima atomic bomb. A fireball this big is only expected about two or three times every 100 years.
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- At about noon local time on December 18, the asteroid sped through our atmosphere at a speed of 72,000 miles per hour , on a steep trajectory of seven degrees.
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- Measuring several meters in size, the space rock exploded 16 miles above the Earth's surface, with an impact energy of 173 kilotons.
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- That was 40% the energy release of Chelyabinsk ateroid, but it was over the Bering Sea so it did not have the same public effect.
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- Astronomers believe that steroid impact risks are underplayed. Military satellites picked up this blast in December and NASA was notified of the event by the US Air Force. It was not something NASA had discovered.
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- The fireball came in over an area not too far from routes used by commercial planes flying between North America and Asia. So researchers have been checking with airlines to see if there were any reported sightings of the event.
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- In 2005, Congress tasked NASA with finding 90% of near-Earth asteroids of 460 feet in diameter or larger by 2020. Space rocks of this size are expected to affect whole regions if they collide with Earth. But scientists estimate it will take them another 30 years to fulfill this congressional directive.
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- Once an incoming object is identified, NASA has had some notable success at calculating where on Earth the impact will occur, based on a precise determination of its orbit.
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- In June 2018, a small 10 foot asteroid was discovered by a ground-based observatory in Arizona eight hours before impact. The Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory then made a precision determination of its orbit, which was used to calculate a probable impact location. This showed the rock was likely to hit southern Africa.
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- Just as the calculation suggested, a fireball was recorded over Botswana by security camera footage. Fragments of the meteor were later found in the area. Japan's Himawari satellite had also captured the fireball's steep descent.
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- This latest event over the Bering Sea shows that larger objects can collide with us without warning, underlining the need for enhanced monitoring. A more robust monitoring network would be dependent not only on ground telescopes, but space-based observatories as well.
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- A mission concept in development would see a telescope called “NeoCam” launched to a gravitational balance point in space, where it would discover and characterize potentially hazardous asteroids larger than 140meters.
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- If the mission does not launch, projections are that it would take us many decades to get there with the existing suite of ground-based surveys. But , if we have an infrared based telescope in orbit we could attain the capability much faster.
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- How important is it to see what’s coming?
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- Other reviews available:
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- 2296 - Asteroids are rocky world orbiting our Sun. Asteroids can reach as large as Ceres that is 583 miles across. More than 150 asteroids are known t have companion moons. Ironically, the collisions that could mean death to humans may be the same reason we are alive today.
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- 2250 - Asteroid visits and impacts. We had a spacecraft visit the asteroid Itokawa in 2005 and the asteroids Ryugu and Bennu in 2019.
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- 2226 Asteroid Ryugu. Spacecraft landed on the surface on September 2018. What have we learned?
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- 2209 Asteroid Oumuamua is from another sola system outside our own.
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- 2203 Asteroid Bennu. Arrived December 2019 and will inspect every square inch of the asteroid before returning home in 2023.
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- 2044 - Oumuamua is a needle shaped asteroid that will exit solar system. This Review lists 15 other reviews about asteroids.
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- 1923 - When will the big one hit? In 2017 50 asteroids passed us at a distance closer than our Moon.
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- 1825 - Asteroids responsible for evolution on Earth?
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- 1554 - Asteroids are fossils with stories.
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- 1375 - There is an asteroid following us in orbit.
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- 1309 - Vesta and Ceres get a visit from the Dawn spacecraft.
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- 1296 - When an asteroid hit Manson , Iowa?
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- March 18, 2019
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-------------------------- Tuesday, March 19, 2019 --------------------------
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