Asteroid 2015 BA511 passed by the Earth at a distance of 14 800 000 km (38.5 times the average distance between the Earth and the Moon, or 9.9% of the average distance between the Earth and the Sun), slightly before 4.10 am GMT on Tuesday 24 February 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2015 BA511 has an estimated equivalent diameter of 21-65 m (i.e. it is estimated that a spherical object with the same volume would be 21-65 m in diameter), and an object of this size would be expected to break up in the atmosphere between 21 and 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 12 megatons of TNT (roughly 700 times the energy released by the Hiroshima bomb), then being directly underneath it might be fairly unpleasant.
The calculated orbit of 2015 BA511. JPL Small Body Database.
2015 BA511 was discovered on 22 January 2015 (33 days befoe its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2015 BA511 implies that it was the 12 776th asteroid (asteroid A511) discovered in the second half of January 2015 (period 2015 B).
While 2015 BA511 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 1063 day orbit, at an angle of 4.6° to the plane of the Solar System, that takes it from 1.07 AU from the Sun (1.07 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 3.01 AU from the Sun, (3.01 times the distance at which the Earth orbits the Sun and roughly twice the distance at which the planet Mars orbits the Sun). As a Near Earth Object that remains strictly outside the orbit of the Earth it is classed as an Amor Family Asteroid.
See also...
Asteroid 2015 CA40 passed by the Earth at a distance of 2 419 000 km (6.32 times the average distance between the Earth and the Moon, or 1.6% of the average distance between the Earth and the Sun), slightly before 9.50 pm GMT on Monday 23 February 2015. There was no danger of the asteroid hitting...
Asteroid 2014 EK24 passed by the Earth at a distance of 6 129 000 km (15.94 times the average distance between the Earth and the Moon, or 4.1% of the average distance between the Earth and the Sun), slightly after 5.30 pm GMT on Monday 23 February...
Asteroid 2015 DU passed by the Earth at a distance of 3 068 000 km (7.97 times the average distance between the Earth and the Moon, or 2% of the average distance between the Earth and the Sun), at about 10.00 am GMT on Monday 23 February 2015...
Follow Sciency Thoughts on Facebook.