Asteroid 2018 GN passed by the Earth at a distance of about 430 200 km (1.12 times the average distance between the Earth and the Moon, or 0.23% of the distance between the Earth and the Sun), slightly before 3.00 pm GMT on Monday 9 April 2018. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2018 GN has an estimated equivalent diameter of 11-34 m (i.e. it is estimated that a spherical object with the same volume would be 11-34 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) in the atmosphere between 30 and 15 km above the ground, with only fragmentary material reaching the Earth's surface.
2018 GN was discovered on 8 April 2018 (the day before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2018 GN implies that it was the 13th asteroid (asteroid N) discovered in the first half of April 2018 (period 2018 G).
2018 GN has a 1370 day orbital period and an eccentric orbit tilted at an angle of 1.44° to the plane of the Solar System, which takes it from 0.64 AU from the Sun (i.e. 64% of he average distance at which the Earth orbits the Sun, inside the orbit of the planet Venus) to 4.19 AU from the Sun (i.e. 419% of the average distance at which the Earth orbits the Sun, and more than twice as distant from the Sun than the planet Mars). 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 the asteroid has occasional close encounters with the Earth, with the next predicted in April 2071. The asteroid also has occasional encounters with the planet Jupiter, with the last having occurred in January 1990.
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