Asteroid 2020 GA2 passed by the Earth at a distance of about 3 282 000
km (8.55 times the average distance between the Earth and the Moon, or
2.19% of the distance between the Earth and the Sun), slightly after 3.55 pm
GMT on Saturday 11 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 GA2 has an estimated
equivalent
diameter of 110-350 m (i.e. it is estimated that a spherical object with
the same volume would be 110-350 m in diameter), and an 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 600-120 000 times as powerful as the
Hiroshima
bomb. Such an impact would result in an impact crater 15.-5.0 km in
diameter
and devastation on a global scale, as well as climatic effects that
would last decades or even centuries.
2020 GA2 was discovered on 9 April 2020 (two days before its closest approach to the Earth) by the Atlas MLO Telescope at Mauna Loa Observatory in Hawaii. The designation 9 April 2020 implies that the asteroid was the 49th object (object A2 -
in numbering asteroids the letters A-Z, 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.) discovered in the first half of April 2020 (period 2020 G).
2020 GA2 has a 529 day (1.45 year) orbital period, with an elliptical
orbit tilted at
an angle of 42.9° to the plain of the Solar System which takes in to
0.73 AU from the Sun (73% of the distance at which the Earth orbits the
Sun) and out to 1.82 AU (1.82% 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 April 1933 and the next predicted
in October 2022. 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 GA2
is also
classified as a Potentially Hazardous Asteroid.
See also...
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