Asteroid 2001 QC34 passed by the Earth at a distance of 16 190 000 km (over 42 times the average distance between the Earth and the Moon) at about 7.35 pm GMT on Wednesday 2 April 2014. There was no danger of the asteroid hitting us, although had it done so it would have been likely to have caused severe problems. 2001 QC34 has an estimated diameter of between 180 m and 570 m, and an object of this size would be predicted to be capable of punching straight through the Earth's atmosphere, and impacting directly into the ground in an explosion between 6000 and 60 000 times as large as the explosion caused by the Hiroshima bomb, resulting in a crater 2-8 km in diameter and devastation over a very wide area, as well as climatic effects lasting decades.
The calculated orbit of 2001 QC34. JPL Small Body Database Browser.
2001 QC34 was discovered on 17 August 2001 by the Near-Earth Asteroid Tracking system at Palomar Observatory. The dseignation 2001 QC34 implies that it was the 853rd asteroid (asteroid C34) discovered in the second half of August 2001 (period 2001 Q).
2001 QC34 has a 428 day orbital period and an eccentric orbit that takes it from 0.91 AU from the Sun (i.e. 91% of the average distance at which the Earth orbits the Sun) to 1.34 AU from the Sun (i.e. 134% of the average distance at which the Earth orbits the Sun). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer).
Because of the similarity in the orbital period of 2001 QC34 and the Earth, combined with an orbit that never takes it more than 0.34 AU from our orbital path, means that flybys of Earth by 2001 QC34 are fairly frequent events, the last having occurred in October 2013, and the next scheduled for October 2019. Due its large size and Earth-orbit crossing trajectory, 2001 QC34 is classed as a Potentially Hazardous Asteroid.
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