Space is once again in the News with the upcoming close encounter between the Earth-Moon system and asteroid 2005 YU55 on Wednesday 9 November 2011 Australian time. Closest approach will be at 9.38 am AEST (add one hour if your location follows daylight savings time) – unfortunately preventing Australian amateur astronomers from viewing the asteroid through small telescopes at the time of closest approach. Before and after the time of closest approach, the small size of the asteroid will mean that it will be too faint to be located visually through amateur telescopes from Australia.
From a JPL/NASA media release: ‘The orbit of asteroid 2005 YU55 is well understood. At the point of closest approach, it will be no closer than 201,700 miles (324,600 kilometers) or 0.85 the distance from the moon to Earth. The gravitational influence of the asteroid will have no detectable effect on anything here on Earth, including our planets tides or tectonic plates. Although 2005 YU55 is in an orbit that regularly brings it to the vicinity of Earth (and Venus and Mars), the 2011 encounter with Earth is the closest this space rock has come for at least the last 200 years.’ 2005 YU55 will not impact the Earth, and there is no danger of it doing so.
Asteroid (or minor planet as professional astronomers prefer to call them today) 2005 YU55 is 400 meters in diameter and the colour of charcoal. Unfortunately, this means that it will be difficult to locate as it will be relatively faint. At closest approach, 2005 YU55 is expected to reach only magnitude 11.2 (significantly fainter than the unaided eye can see). Having a bright Moon in the sky also won’t help.
