Asteroid 2002 LX passed by the Earth at a distance of about 18 000 000 km (46.7 times the average distance between the Earth and the Moon, or 12.0% of the distance between the Earth and the Sun), slightly before 3.55 pm GMT on Monday 19 February 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2002 LX has an estimated equivalent diameter of 120-390 m (i.e. it is estimated that a spherical object with the same volume would be 120-390 m in diameter), and an object of this size would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be 3000 to 150 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater 1.5-6 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.
The calculated orbit of 2002 LX. Minor Planet Center.
2002 LX was discovered on 3 June 2002 by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research Laboratory in Socorro, New Mexico. The designation 2002 LX4 implies that it was the 23rd asteroid (asteroid X) discovered in the first half of June 2002 (period 2002 L).
2002 LX has a 1456 day orbital period and an eccentric orbit tilted at an angle of 3.24° to the plane of the Solar System, which takes it from 0.83 AU from the Sun (i.e. 83% of he average distance at which the Earth orbits the Sun) 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 last having occurred in March 2014 and the next predicted in February 2022. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2017 YH1 is also classified as a Potentially Hazardous Asteroid. 2002 LX also has occasional close encounters with the planet Venus, which it last passed in June 1996.
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