Asteroid 2020 VT3 passed by the Earth at a distance of about 470 800 km (1.23 times the average distance between the Earth and the Moon, or 0.33% of the distance between the Earth and the Sun), slightly after 7.40 pm GMT on Sunday 15 November 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 VT3 has an estimated equivalent diameter of 3-10 m (i.e. it is estimated that a spherical object with the same volume would be 3-10 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) more than 31 km above the ground, with only fragmentary material reaching the Earth's surface.
2020 VT3 was discovered on 12 November 2020 (three days before its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2020 VT3 implies that the asteroid was the 94th object (asteroid T3 - in numbering asteroids the letters A-Z excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 26, A2 = 51, etc., which means that T3 = (25 x 3) + 19 = 94) discovered in the first half of November 2020 (period 2020 V - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).
2020 VT3 has a 541 day (1.48 year) orbital period, with an elliptical orbit tilted at an angle of 0.31° to the plain of the Solar System which takes in to 0.83 AU from the Sun (83% of the distance at which the Earth orbits the Sun) and out to 1.76 AU (1.76% of the distance at which the Earth orbits the Sun, and more than the distance at which the planet 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 2020 VT3 has occasional close encounters between the asteroid and Earth, with the last thought to have happened in January 2018 and the next predicted in May 2021. The asteroidalso has occasional close encounters with the planets Venus, which it last cam close to in May 1994 and is next predicted to pass in September 2041, and Mars, which it last came close to in September this year (2020) and is expected to pass again in November 2025. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.
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