Asteroid 2014 KC46 passed by the Earth at a distance of about 4 331 000 km (11.26 times the average distance between the Earth and the Moon), slightly after 9.40 pm GMT on Sunday 8 June 2014. There was no danger of the asteroid hitting us, though were it to do so it would have presented a moderate threat. 2014 KC46 has an estimated equivalent diameter of 52-160 m (i.e. it is estimated that a spherical object with the same volume would be 52-160 m in diameter), and an object towards the upper end of this range would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be 4200 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater about 2 km in diameter and devastation on a global scale, as well as climatic effects that would last years.
The calculated orbit of 2014 KC46. JPL Small Body Database Browser.
2014 KC46 was discovered on 25 May 2014 (fourteen days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2014 KC46 implies that it was the 1153rd asteroid (asteroid C46) discovered in the second half of May 2014 (period 2014 K).
2014 KC46 has an 1372 day year orbital period that takes it from 0.91 AU from the Sun (i.e. 70% of the average distance at which the Earth orbits the Sun, and slightly inside the orbit of Venus) to 4.13 AU from the Sun (i.e. 413% of the average distance at which the Earth orbits the Sun, considerably more than twice the distance at which the planet Mars 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).
See also...
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