Close shave from an undetected asteroidBy Eddie Irizarry in SPACE | July 25, 2017
http://earthsky.org/space/asteroid-2017-oo1-close-pass-undetectedWhoosh! Astronomers discovered a small asteroid – now designated as asteroid 2017 OO1 – on July 23. That was 3 days after it passed 1/3 the moon’s distance from Earth.
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This means the asteroid’s closest approach occurred 2.5 to 3 days before it was seen. Asteroid 2017 OO1 flyby had passed at about one-third the Earth-moon distance, or about 76,448 miles (123,031 km).
Although that’s still a safe distance, a fact that stands out is that asteroid 2017 OO1 is about three times as big as the house-sized asteroid that penetrated the skies over Chelyabinsk, Russia in February, 2013, breaking windows in six Russian cities and causing more that 1,000 people to seek treatment for injuries, mostly from flying glass.
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