Asteroid 2013 GY7 passed by the Earth at a distance of about 15 304
000
km (39.9 times the average distance between the Earth and the Moon, or 10.0% of the distance between the Earth and the Sun), slightly before 4.10 pm
GMT on Monday 5 October 2020. There was no danger of
the asteroid hitting us, though were it to do so it would not have
presented a significant threat. 2013 GY7 has an estimated
equivalent
diameter of 160-520 m (i.e. it is estimated that a spherical object
with
the same volume would be 160-520 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 directly with an
explosion that would be 4000-450 000 times as powerful as the
Hiroshima
bomb. Such an impact would result in an impact crater roughly 2.5-8 km
in
diameter
and devastation on a global scale, as well as climatic effects that
would last years or even decades.
2013 GY7 was discovered on 3 April 2013 by the University of Hawaii's PANSTARRS telescope. The
designation 2013 GY7 implies that it was the 192nd asteroid (asteroid Y7 -
in numbering asteroids the letters A-Y, excluding I, are assigned
numbers from 1 to 24, with a number added to the end each time the
alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that Y7 = (24 x 7) + 24 = 192)
discovered in the first half of April 2013 (period 2013 G).
2013 GY7 has a 508 day (1.39 year) orbital period, with an elliptical
orbit tilted at
an angle of 29.6° to the plain of the Solar System which takes in to
0.95 AU from the Sun (95% of the distance at which the Earth orbits the
Sun) and out to 1.53 AU (153% of the distance at which the Earth orbits
the sun and slightly further from the Sun than the planet Mars).
This means that close
encounters between the asteroid and Earth are fairly common, with the
last thought to have happened in April this year (2020) and the next predicted
in April next year (2021). 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). As
an asteroid probably larger than 150 m in diameter that occasionally
comes within 0.05 AU of the Earth, 2013 GY7 is also classified
as a Potentially Hazardous Asteroid.
See also...
