Large asteroid gliding past Earth today

8 Nov 2011

NASA said this radar image of asteroid 2005 YU55, was obtained on 7 November,at 11.45am PST, when the space rock was at 3.6 lunar distances, about 1.38m km from Earth

Asteroid 2005 YU55 will today fly past Earth slightly closer than the moon’s orbit, making its closest approach at 3.28pm PST (11.30pm GMT). The last time a space rock this large came as close to Earth was in 1976, although astronomers did not know about the fly-by at the time, according to NASA.

The next known approach of an asteroid this size (comparable to an aircraft) will be in 2028. Today’s Earth passing by the asteroid will pose no threat to human safety, however, the NASA Near-Earth Object Observations Program has confirmed.

Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin today when the asteroid will make its closest approach to Earth.

Tracking of the aircraft carrier-sized asteroid began at Goldstone at 9.30am PDT on 4 November, with the 70-metre antenna and lasted about two hours, with an additional four hours of tracking planned each day from 6-10 November.

Trajectory of the asteroid

At the point of its closest approach, asteroid 2005 YU55 will be no closer than 324,600km as measured from the centre of Earth, or about 0.85 times the distance from the moon to Earth.

NASA said the gravitational influence of the asteroid will have no detectable effect on Earth, including tides and tectonic plates. Although the asteroid is in an orbit that regularly brings it to the vicinity of Earth, Venus and Mars, the 2011 encounter with Earth is the closest it has come for at least the last 200 years.

Yesterday, NASA’s Deep Space Network antenna in Goldstone, California, captured new radar images of Asteroid 2005 YU55.

NASA detects, tracks and characterises asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program at the Jet Propulsion Laboratory (JPL) in Pasadena, California, more commonly called ‘Spaceguard’, discovers these objects, characterises some of them, and plots their orbits to determine if any could be potentially hazardous to our planet.

Carmel Doyle was a long-time reporter with Silicon Republic