Asteroid 2015 CL passed by the Earth at a distance of 1 659 000 km
(4.32 times the average distance between the Earth and the Moon, or 1.1
%
of the average distance between the Earth and the Sun), at about 1.20 slightly before 10.40 pm GMT on Sunday 8 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 CL has an estimated equivalent diameter of 16-49 m
(i.e. it is estimated that a spherical object with the same volume
would be 16-49 m in diameter), and an object of this size would be
expected to break up in the atmosphere between 29 and 9 km above the
ground, with only fragmentary material reaching the Earth's surface.
The calculated orbit of 2015 CL JPL Small Body Database.
2015 CL was discovered on 8 February 2015 (the day of its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope
on Mount Haleakala on Maui. The designation 2015 CL implies that it
was the eleventh asteroid (asteroid L) discovered in the first half of February 2015 (period 2015 C).
2015 CL has a 228 day orbital period, with an elliptical orbit tilted
at an angle of 3° to the plain of the Solar System which takes in to
0.32 AU from the Sun (32% of the distance at which the Earth orbits the
Sun, considerably inside the orbit of Mercury) and out to 1.14 AU (14%
further away from the Sun than the Earth). This means that
close encounters between the asteroid and Earth are fairly common, with
the last thought to have happened in December 2013 and the next
predicted in December 2017. Although it does cross the Earth's orbit and
is briefly further from the Sun on each cycle, 2015 spends
most of its time closer to the Sun than we are, and is therefore
classified as an Aten Group Asteroid.
See also...
Asteroid 2015 BF92 passes the Earth. Asteroid 2015 BF92 passed by the Earth at a distance of 3 267 000 km
(8.5 times the average distance between the Earth and the Moon, or 2.2 %
of the average distance between the Earth and the Sun), slightly before
10.10 pm GMT on Saturday 7 February... 
Asteroid
2009 DT10 passed by the Earth at a distance of 8 202 000 km (21.34
times the average distance between the Earth and the Moon, or 5.5 % of
the average distance between the Earth and the Sun), slightly after 4.14
am GMT on Saturday 7 February...
Asteroid 2015 BX509 passes the Earth.
Asteroid 2015 BX509 passed by the Earth at a distance of 13 610 000 km
(35.48 times the average distance between the Earth and the Moon, or
9.1% of the average distance between the Earth and the Sun), slightly
before 3.25 pm GMT on Thursday 5 February...
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