Asteroid 2015 CM passed by the Earth at a distance of 3 236 000 km
(8.42 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 8.40 am GMT on Monday 9 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 CM has an estimated equivalent diameter of 9-30 m
(i.e. it is estimated that a spherical object with the same volume
would be 9-30 m in diameter), and an object of this size would be
expected to break up in the atmosphere between 33 and 16.5 km above the
ground, with only fragmentary material reaching the Earth's surface.
The calculated orbit of 2015 CM. JPL Small Body Database.
2015 CM was discovered on 8 February 2015 by the University of Arizona's Catalina Sky Survey,
which is located in the Catalina Mountains north of Tucson. The
designation 2015 CM implies that it was the twelth asteroid (asteroid M)
discovered in the first half of February 2015 (period 2015 M).
While 2015 CM occasionally comes near to the Earth, it does not
actually cross our orbital path. It has an elliptical 392 day orbit, at
an angle of 11.4° to the plane of the Solar System, that takes it from
1.005 AU from the Sun (1.005 times the average distance at which the Earth
orbits the Sun), slightly outside our orbit, to 1.09 AU from the Sun,
(1.09 times the distance at which the Earth 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. This orbit also means that close encounters between 2015 CM and the Earth are extremely common, with the last having occured in September 2014 and the next predicted for July this year.
See also...
Asteroid 2015 CL passes the Earth. 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...
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...
Follow Sciency Thoughts on Facebook.