Asteroid 2016 AO8 passed by the Earth at a distance of 18 950 000 km (49.4 times the average distance between the Earth and the Moon, or 12.7% of the average distance between the Earth and the Sun), slightly before 0.55 am GMT on Saturday 2 January 2016. There was no danger of the asteroid hitting us, though had it done so it would have presented a genuine threat. 2016 AO8 has an estimated equivalent diameter of 30-94 m (i.e. a spherical body with the same mass would be 30-94 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 30 megatons (about 1765 times the explosive energy of the Hiroshima bomb), causing devastation over a wide area and creating a crater about 1 km across, and resulting in global climatic problems that could last for years.
2016 AO8 was discovered on 3 January 2016 (the day after its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2016 AO8 implies that it was the 214th asteroid (asteroid O8) discovered in the first half of January 2016 (period 2016 A).
2016 AO8 has an 1716 day orbital period and an eccentric orbit tilted at an angle of 8.58° to the plane of the Solar System that takes it from 1.01 AU from the Sun (i.e. 101 % of the average distance at which the Earth orbits the Sun) to 4.52 AU from the Sun (i.e. 452% of the average distance at which the Earth orbits the Sun, over three times the distance at which the planet Mars orbits). It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is always outside the Earth's orbit).
See also...
Asteroid 2015 XC352 passes the Earth. Asteroid
2015 XC352 passed by the Earth at a distance of 1 991 000 km (5.18 times
the average distance between the Earth and the Moon, or 1.33% of
the average distance between the Earth and the Sun),
slightly after 7.00 pm GMT on Wednesday...
Asteroid 2015 YV9 passes the Earth. Asteroid
2015 YV9 passed by the Earth at a distance of 3 602 000 km (9.37 times
the average distance between the Earth and the Moon, or 2.4`% of
the average distance between the Earth and the Sun),
slightly after 3.00 pm GMT on Saturday 26 December 2015...
January's first meteor shower: The 2015 Quadrantids. The Quadrantid Meteor Shower is one of the brightest meteor showers of
the year, often producing over 100 meteors per hour at its peak, which
falls on the night...
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