Asteroid 2014 MJ55 passed by the Earth at a distance of about 11 080 000 km (28.83 times the average distance between the Earth and the Moon, or 7.4% of the average distance between the Earth an the Sun), slightly after 12.20 pm GMT on Wednesday 23 July 2014. There was no danger of the asteroid hitting us, though were it to do so it would have presented a serious threat. 2014 MJ55 has an estimated equivalent diameter of 36-110 m (i.e. it is estimated that a spherical object with the same volume would be 36-110 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 with an energy equivalent to about 45 megatons of TNT (roughly 2500 times the energy of the Hiroshima bomb). Such an event would result in a crater about 1.5 across, cause devastation on a global scale and would have the potential to affect the climate globally for years to centuries after the impact event.
The calculated orbit of 2014 MJ55. JPL Small Body Database Browser.
2014 MJ55 was discovered on 30 June 2014 (23 days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2014 MJ55 implies that it was the 1384th asteroid (asteroid J55) discovered in the second half of June 2014 (period 2014 M).
2014 MJ55 has a 954 day year orbital period and an eccentric orbit tilted at an angle of 7.4° to the plane of the Solar System, that takes it from 0.87 AU from the Sun (i.e. 87 % of the average distance at which the Earth orbits the Sun) to 2.91 AU from the Sun (i.e. 291% of the average distance at which the Earth orbits the Sun, slightly less 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...
Asteroid 2014 MA6 passed by the Earth at a distance of 7 275 000 km (18.93 times the average distance between the Earth and the Moon, or 4.9% of the average distance between the Earth and the...
Asteroid 2013 YG passed by the Earth at a distance of 19 190 000 km (49.68 times the average distance between the Earth and the Moon, or 12.7% of the average distance between the Earth and the...
Asteroid families are groups of objects thought to have a common origin, typically the catastrophic break-up of a parent body at some remote point in the past, which has left a population of asteroids...
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