Thursday 2 April 2015

Asteroid 2015 FL35 passes the Earth.

Asteroid 2015 FL35 passed by the Earth at a distance of 3 912 000 km (10.2 times the average distance between the Earth and the Moon, or 2.61% of the average distance between the Earth and the Sun), at about 1.45 pm GMT on Wednesday 25 March 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2015 FL35 has an estimated equivalent diameter of 26-82 m (i.e. it is estimated that a spherical object with the same volume would be 26-82 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 between 18 and 0.5 km above the ground, with only fragmentary material reaching the Earth's surface, although since an object at the upper end of this range would be expected to release an amount of energy equivalent to about 27 megatons of TNT (roughly 1600 times the energy released by the Hiroshima bomb), then being directly underneath it might be fairly unpleasant.

The calculated orbit of 2015 FL35. JPL Small Body Database.

2015 FL35 was discovered on 22 March 2015 (two days before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2015 FL53 implies that it was the 886th asteroid (asteroid L35) discovered in the secondt half of March 2015 (period 2015 F).

2015 FL35 has an 532 day orbital period and an eccentric orbit tilted at an angle of 24.4° to the plane of the Solar System, which takes it from 1.00 AU from the Sun (i.e. 100% of the average distance at which the Earth orbits the Sun) to 1.56 AU from the Sun (i.e. 1.56% of the average distance at which the Earth orbits the Sun, slightly greater than the distance at which the planet 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). This also means that close encounters between 2015 FL35 and the Earth are quite common, with the last having occurred in September 1935 next predicted for August this year.

See also...

Asteroid 2015 FN34 passes the Earth. 

Asteroid 2015 FN34 passed by the Earth at a distance of 3 076 000 km (7.99 times the average distance between the Earth and the Moon, or 2.06% of the average distance between the Earth and the Sun), slightly before 5.20 am GMT on Wednesday 25 March...




Asteroid 2015 DJ215 passed by the Earth at a distance of 12 430 000 km (32.4 times the average distance between the Earth and the Moon, or 8.38% of the average distance between the Earth and the Sun), slightly before 5.30 pm GMT on Sunday 22 March...




Asteroid 2015 FC117 passed by the Earth at a distance of 6 542 000 km (17.0 times the average distance between the Earth and the Moon, or 4.37% of the average distance between the Earth and the Sun), slightly 6.45 am GMT on Sunday 22 March 2015....




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