Saturday 18 April 2020

Asteroid 2020 GA2 passes the Earth.

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.

 The calculated orbit of 2020 GA2. JPL Small Body Database.

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...

https://sciencythoughts.blogspot.com/2020/04/the-lyrid-meteor-shower.htmlhttps://sciencythoughts.blogspot.com/2020/04/identifying-worlds-oldest-impact.html
https://sciencythoughts.blogspot.com/2020/04/asteroid-2020-gf1-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/04/estimating-potential-for-life-to-have.html
http://sciencythoughts.blogspot.com/2020/04/microbial-life-in-post-impact-chicxulub.htmlhttps://sciencythoughts.blogspot.com/2020/04/asteroid-2015-fc35-passes-earth.html
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