Monday 6 April 2020

Asteroid 2011 GM44 passes the Earth.

Asteroid 2011 GM44 passed by the Earth at a distance of about 11 663 000 km (30.4 times the average distance between the Earth and the Moon, or 7.80% of the distance between the Earth and the Sun), at about 7.30 am GMT on Monday 30 March 2020. There was no danger of the asteroid hitting us, though were it to do so it would have presented a considerable threat. 2011 GM44 has an estimated equivalent diameter of 220-680 m (i.e. it is estimated that a spherical object with the same volume would be 220-680 m in diameter), and an object 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 23 000-825 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater 3-10 km in diameter and devastation on a global scale, as well as climatic effects that would last decades or even centuries.

 Image of 2011 GM44 taken on 5 April 2011. The image is a composite of eleven 20 second esposures taken with the Tzec Maun Foundation's Takahashi TOA-150 f/7.3 refractor telescope at the Siding Spring Observatory. The dotted lines are stars, which have moved between exposures, with the single point at the centre of the image, indicated by the two lines, being the asteroid. Giovanni Sostero and Ernesto Guido/Comets & Asteroids - Small Bodies of the Solar System.

2011 GM44 was discovered on 5 April 2011 at Siding Spring Observatory in Australia. The designation 2011 GM44 implies that it was the 1068th asteroid (asteroid M44 - 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 M44 = 12 + (24 X 44) = 1068) discovered in the first half of May 2011 (period 2011 G).

 The calculated orbit of 2011 GM44. JPL Small Body Database.

2011 GM44 has a 252 day orbital period, with an elliptical orbit tilted at an angle of 49.3° to the plain of the Solar System which takes in to 0.38 AU from the Sun (38% of the distance at which the Earth orbits the Sun, and roughly the distance at which Mercury orbits the Sun) and out to 1.19 AU (19% further away from the Sun than the Earth). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in March 2018 and the next predicted in April 2022. Although it does cross the Earth's orbit and is briefly further from the Sun on each cycle, 2011 GM44 spends most of its time closer to the Sun than we are, and is therefore classified as an Aten Group Asteroid. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, (2011 GM44 is also classified as a Potentially Hazardous Asteroid. The asteroid also has occasional close encounters with the planet Mercury, with the last having happened in April 2008, and the next predicted for March 2024.

See also...

https://sciencythoughts.blogspot.com/2020/03/asteroid-2020-fx4-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/03/asteroid-2020-fp5-passes-earth.html
https://sciencythoughts.blogspot.com/2020/03/asteroid-2000-bo28-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/03/asteroid-2020-fd-passes-earth.html
https://sciencythoughts.blogspot.com/2020/03/asteroid-2020-fc2-passes-earth.htmlhttps://sciencythoughts.blogspot.com/2020/03/asteroid-2004-re84-passes-earth.html
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