Asteroid 2015 JH2 passed by the Earth at a distance of 11 830 000 km (30.8 times the average distance between the Earth and the Moon, or 7.91 % of the average distance between the Earth and the Sun), slightly before 2.40 am GMT on Thursday 9 July 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented a considerable threat. 2015 JH2 has an estimated equivalent diameter of 65-210 m (i.e. a spherical body with the same mass would be 65-210 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 300 megatons (about 17 600 times the explosive energy of the Hiroshima bomb), causing devastation over a wide area and creating a crater over 3 kilometers across, and resulting in global climatic problems that could last for decades or even centuries.
The calculated orbit of 2015 JH15. JPL Small Body Database.
2015 JH2 was discovered on 15 May 2015 (56 days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2015 JH2 implies that it was the 58th asteroid (asteroid H2) discovered in the first half of May 2015 (period 2015 J).
While 2015 JH2 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 1033 day orbit, at an angle of 5.12° to the plane of the Solar System, that takes it from 1.07 AU from the Sun (1.07 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 2.93 AU from the Sun, (2.93 times the distance at which the Earth orbits the Sun and almost double the 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 between the asteroid and Earth are extremely common, with the last having occurred in August 1998 and the next predicted in May 2032.
See also...
Comet C/2014 Q1 (PANSTARRS) reached its perihelion (the closest point on its orbit to the Sun) on Monday 6 July 2015, when it was 0.31 AU from the Sun (i.e. 0.31 times the average distance at which the...
Asteroid 2015 MX103 passed by the Earth at a distance of 4 389 000 km (11.4 times the average distance between the Earth and the Moon, or 2.93% of the average distance between the Earth and the Sun), slightly before 4.45 pm GMT on Monday 22 June...
Asteroid 2015 LQ21 passed by the Earth at a distance of 4 983 000 km (13.0 times the average distance between the Earth and the Moon, or 3.33% of the average distance between the Earth and the Sun), slightly before 7.00 pm GMT on Thursday 18...
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