Sciency Thoughts: Asteroid 177049 (2003 EE16) passes the Earth.

Asteroid 177049 (2003 EE16) passed by the Earth at a distance of about 14 460 000 km (37.61 times the average distance between the Earth and the Moon), slightly after 9.50 pm GMT on Tuesday 1 July 2014. There was no danger of the asteroid hitting us, though were it to do so it would have presented a serious threat. 177049 (2003 EE16) 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 with an energy equivalent to about 300-15 500 megatons of TNT (roughly 17 500-912 000 times the energy of the Hiroshima bomb). Such an event would result in a crater between 3.25 and 9 km across, cause devastation on a global scale and would have the potential to affect the climate globally for decades to centuries after the impact event.

The calculated orbit of 177049 (2003 EE16). JPL Small Body Database Browser.

177049 (2003 EE16) was discovered on 3 March 2003 by the University of Arizona's Kitt Peak-Spacewatch Project at the Steward Observatory in the Catalina Mountains north of Tucson. The designation 2003 EE16 implies that it was the 405th asteroid (asteroid E16) discovered in the first half of March 2003 (period 2003 E), while the designation 177049 indicates that it was the 177049th asteroid discovered overall - asteroids are not generally given this longer designation for some time after discovery, to avoid false detections.

177049 (2003 EE16) has a 617 day year orbital period and an eccentric orbit that takes it from 0.54 AU from the Sun (i.e. 0.54 % of the average distance at which the Earth orbits the Sun, considerably inside the orbit of Venus) to 2.29 AU from the Sun (i.e. 229% of the average distance at which the Earth orbits the Sun, considerably outside the orbit of Mars). 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 means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in February 2013 and the next predicted in August 2019. As an asteroid on an Earth-orbit crossing trajectory which is large enough to cause serious harm should it collide with Earth it is also classified as a Potentially Hazardous Asteroid.

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Monday, 7 July 2014

Asteroid 177049 (2003 EE16) passes the Earth.