Wednesday, 18 November 2015

Asteroid 2015 VY2 passes the Earth.

Asteroid 2015 VY2 passed by the Earth at a distance of 18 550 000 km (48.6 times the average distance between the Earth and the Moon, or 12.4% of the average distance between the Earth and the Sun), slightly after 10.00 pm GMT on Wednesday 11 November 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented a genuine threat. 2015 VY2 has an estimated equivalent diameter of 38-120 m (i.e. a spherical body with the same mass would be 38-120 m in diameter), and an object towards the upper end of this range would pass through the atmosphere and directly impact the ground with a force of about 55 megatons (about 3235 times the explosive energy of the Hiroshima bomb), causing devastation over a wide area and creating a crater over 1.5 km across, and resulting in global climatic problems that could last for years or even decades.
 
  The calculated orbit of 2015 VY2. JPL Small Body Database.
 
2015 VY2 was discovered on 6 November 2015 (five days after 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 2015 VY2 implies that the asteroid was the 74th object (object Y2) discovered in the first half of November 2015 (period 2015 V).
 
2015 VY2 has a 573 day orbital period and an eccentric orbit tilted at an angle of 15.8° to the plane of the Solar System that takes it from 0.49 AU from the Sun (i.e. 49% of the average distance at which the Earth orbits the Sun, and slightly outside the orbit of Mercury) to 2.21 AU from the Sun (i.e. 221% of the average distance at which the Earth orbits the Sun, considerably more than the distance at which 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). 2015 VY2 also has occasional close encounters with the planet Venus, with the next predicted in February 2016.
 
See also...
 
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