Thursday 31 July 2014

Asteroid 2014 OD4 passes the Earth.

Asteroid 2014 OD4 passed by the Earth at a distance of 12 250 000 km (32.58 times the average distance between the Earth and the Moon, or 8.4% of the average distance between the Earth and the Sun), slightly before 12.45 pm GMT on Sunday 27 July 2014. There was no danger of the asteroid hitting us, though had it done so it would have presented only a moderate threat. 2014 OD4 has an estimated equivalent diameter of 25-78 m (i.e. it is estimated that a spherical object with the same volume would be 25-78 m in diameter), and an object of this size would be expected to break up in the atmosphere between 20 and 1.5 km above the ground, with only fragmentary material reaching the Earth's surface, although being directly beneath an object towards the upper end of this range would probably be quite unpleasant, as it would be expected to explode with the energy equivalent to about 20 megatons of TNT (over a thousand times as powerful as the Hiroshima bomb).

The calculated orbit of 2014 OD4. JPL Small Body Database Browser.

2014 OD4 was discovered on 25 July 2014 (two days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2014 OD4 implies that it was the 104th asteroid (asteroid D4) discovered in the second half of July 2014 (period 2014 O).

While 2014 OD4 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 529 day orbit, at an angle of 18.4° to the plane of the Solar System, that takes it from 1.08 AU from the Sun (1.08 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 1.48 AU from the Sun, (1.48 times the distance at which the Earth orbits the Sun, slightly less than the average distance at which the planet Mars orbits the Sun). As a Near Earth Object that remains strictly outside the orbit of the Earth it is classed as an Amor Family Asteroid. This means that close encounters with the Earth do occasionally occur, with the next predicted for July 2192.

See also...


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 Asteroid 2014 MJ55 passes the Earth.

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