The near-Earth asteroid named 2005 YU55 — on the list of potentially dangerous asteroids — was observed with the Arecibo Telescope's planetary radar on April 19, 2010 when it was about 1.5 million miles from the Earth, which is about 6 times the distance to the moon. Full Story. CREDIT: Arecibo Observatory/Michael Nolan

Mark your calendars for an impressive and upcoming flyby of an asteroid that’s one of the larger potentially perilous space rocks in the heavens – in terms of smacking the Earth in the future. It’s the case of asteroid 2005 YU55, a round mini-world that is about 1,300 feet (400 meters) in diameter. In early November, this asteroid will approach Earth within a scant 0.85 lunar distances. Due the object’s size and whisking by so close to Earth, an extensive campaign of radar, visual and infrared observations are being planned. Asteroid 2005 YU55 was discovered by Spacewatch at the University of Arizona, Tucson’s Lunar and Planetary Laboratory on Dec. 28, 2005. [Photos: Asteroids in Deep Space] En route and headed our way, the cosmic wanderer is another reminder about life here on our sitting duck of a planet.