Asteroid (480936) 2003 QH5 passed by the Earth at a distance of about 13 000 000
km (33.9 times the average distance between the Earth and the Moon, or 8.69% of the distance between the Earth and the Sun), slightly after 11.10 am
GMT on Tuesday 14 July 2020. There was no danger of
the asteroid hitting us, though were it to do so it would not have
presented a significant threat. (480936) 2003 QH5 has an estimated
equivalent
diameter of 180-570 m (i.e. it is estimated that a spherical object
with
the same volume would be 180-570 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 14 700-350 000 times as powerful as the
Hiroshima
bomb. Such an impact would result in an impact crater roughly 3-8 km
in
diameter
and devastation on a global scale, as well as climatic effects that
would last decades or even centuries.
The orbit of (480936) 2003 QH5, and its current position. JPL Small Body Database.
(480936) 2003 QH5 was discovered on 21 August 2003 by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research Laboratory in Socorro, New Mexico. The designation 2003 QH5 implies that it was the 128th asteroid (asteroid H5 -
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 H5 = 8 + (24 X 5) = 128) discovered in the second half of August 2003
(period 2003 Q), while
the designation 480936 implies that it was 480 936th asteroid ever
discovered (asteroids are not given this longer designation immediately
to avoid naming double or false sightings).
(480936) 2003 QH5 has a 517 day (1.41 year) orbital period, with an elliptical
orbit tilted at
an angle of 17.6° to the plain of the Solar System which takes in to
0.98 AU from the Sun (98% of the distance at which the Earth orbits the
Sun, and slightly inside the orbit of the planet Venus) and out to 1.54 AU (154% of the distance at which the Earth orbits
the Sun, and slightly outside the orbit of the planet Mars).
This means that close
encounters between the asteroid and Earth are fairly common, with the
last thought to have happened in March this year and the next predicted
in February 2017. 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, (480936) 2003 QH5 is also classified
as a Potentially Hazardous Asteroid.
See also...
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