Asteroid 2014 EK24 passed by the Earth at a distance of 6 129 000 km (15.94 times the average distance between the Earth and the Moon, or 4.1% of the average distance between the Earth and the Sun), slightly after 5.30 pm GMT on Monday 23 February 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented minor threat. 2014 EK24 has an estimated equivalent diameter of 43-140 m (i.e. it is estimated that a spherical object with the same volume would be 43-140 m in diameter), and an object towards the upper end of this range would pass through the atmosphere and directly impact the ground with a force of about 70 megatons (about 4100 times the explosive energy of the Hiroshima bomb), causing devastation over a wide area and creating a crater over two kilometers across.
The calculated orbit of 2014 EK24. JPL Small Body Database.
2014 EK24 was discovered on 10 March 2014 by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2014 EK24 implies that it was the 610th asteroid (asteroid K24) discovered in the first half of March 2014 (period 2014 E).
2014 EK24 has an 368 day orbital period and an eccentric orbit tilted at an angle of 4.7° to the plane of the Solar System, which takes it from 0.93 AU from the Sun (i.e. 93% of the average distance at which the Earth orbits the Sun) to 1.08 AU from the Sun (i.e. 108% 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). This means that close encounters between the asteroid and Earth are extremely common, with the last having occurred in March 2014 and the next predicted in February 2016.
See also...
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