Asteroid 2020 FM6 passed by the Earth at a distance of about 5 496 000 km (14.3 times the average distance between the Earth and the Moon, or 3.67% of the distance between the Earth and the Sun), at about 4.35 am GMT on Monday 27 April 2020. There was no danger of the asteroid hitting us, though were it to do so it would have presented a considerable threat. 2020 FM6 has an estimated equivalent diameter of 78-250 m (i.e. it is estimated that a spherical object with the same volume would be 78-250 m in diameter), and an object at the upper end of this range 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 35 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater almost 4 km in diameter and devastation on a global scale, as well as climatic effects that would last decades or even centuries.
2020 FM6 was discovered on 25 March 2020 (over a month before its closest encounter with the Earth) by the University of Hawaii's PANSTARRS telescope. The designation 2020 FM6 implies that it was the 156th asteroid (asteroid X4 - 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 M6 = 12 + (24 X 6) = 156) discovered in the second half of March 2020 (period 2020 F).
2020 FM6 has a 582 day (1.59 year) orbital period, with an elliptical orbit tilted at an angle of 15.0° to the plain of the Solar System which takes in to 0.69 AU from the Sun (69% of the distance at which the Earth orbits the Sun, and slightly inside the orbit of the planet Venus) and out to 2.04 AU (204% of the distance at which the Earth orbits the sun and further from the Sun than the planet Mars). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in November 2015 and the next predicted in October 2023. 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). As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2020 FM6 is also classified as a Potentially Hazardous Asteroid. 2020 FM6 also has occassional close encounters with the planet Venus, with the last having happened in August 2004, and the next predicted for August 2039.
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