Asteroid 2020 ME1 passed by the Earth at a distance of about 759 100 km (1.98 times the average distance between the Earth and the Moon, or 0.51% of the distance between the Earth and the Sun), slightly before 6.15 am GMT on Sunday 28 June 2020. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2020 ME1 has an estimated equivalent diameter of 11-33 m (i.e. it is estimated that a spherical object with the same volume would be 11-33 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.
2020 ME1 was discovered on 21 June 2020 (seven days before its closest encounter with the Earth) by the University of Hawaii's PANSTARRS telescope. The designation 2020 ME1 implies that it was the 29th asteroid (asteroid R - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that M1 = (1 x 24 + 5 = 29) discovered in the second half of June 2020 (period 2020 M - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).
2020 ME1 has an 960 day (2.63 year) orbital period and an eccentric orbit tilted at an angle of 1.10° to the plane of the Solar System, which takes it from 0.91 AU from the Sun (i.e. 91% of the the average distance at which the Earth orbits the Sun) to 2.90 AU from the Sun (i.e. 290% of the average distance at which the Earth orbits the Sun, and almost twice the distance at which Mars 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 happen occasionally, with the last thought to have happened in June 1978 and the next predicted in September 2060.The asteroid also sometimes passes close to the planet Mars, with next such encounter predicted in August 2089.
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