Asteroid 2020 QG passed by the Earth at a distance of about 9300
km (0.02 times the average distance between the Earth and the Moon, or
0.01% of the distance between the Earth and the Sun, which is slighly less than 23 times the height at which the International Space Station orbits the Earth, but less than a quater of the height of satellites in geostationary orbits), slightly before 4.10 am
GMT on Sunday 16 August 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 QG has an estimated
equivalent
diameter of 2-6 m (i.e. it is estimated that a spherical object
with
the same volume would be 2-6 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
more than 36 km above the ground, with only fragmentary material
reaching the Earth's surface.
2020 QG was discovered on 14 August 2020 (the day of after its closest approach to the Earth) by the Zwicky Transient Facility at Palomar Observatory. The designation 2020 QG
implies that the asteroid was the 7th object (asteroid G -
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 G = 7) discovered in the second half of August 2020 (period 2020 Q).
2020 QC has a 990 day (2.71 year) orbital period, with an elliptical
orbit tilted at
an angle of 5.47° to the plain of the Solar System which takes in to 1.00 AU from the Sun (the distance at which the Earth orbits the
Sun) and out to 2.90 AU (290% of the distance at which the Earth orbits
the Sun, and outside the orbit of the planet Mars).
This means that close
encounters between the asteroid and Earth are fairly common, with the
the next predicted
in May 2028. 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).
See also...
