Asteroid Approach on November 8
Tracking of the aircraft carrier-sized asteroid will begin at 9:30 a.m. local time (PDT) on Nov. 4, using the massive 70-meter (230-foot) Deep Space Network antenna, and last for about two hours. The asteroid will continue to be tracked by Goldstone for at least four hours each day from Nov. 6 through Nov. 10. Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin on Nov. 8, the same day the asteroid will make its closest approach to Earth at 3:28 p.m. PST.
The trajectory 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 planet's 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.
During tracking, scientists will use the Goldstone and Arecibo antennas to bounce radio waves off the space rock. Radar echoes returned from 2005 YU55 will be collected and analyzed. NASA scientists hope to obtain images of the asteroid from Goldstone as fine as about 7 feet (2 meters) per pixel. This should reveal a wealth of detail about the asteroid's surface features, shape, dimensions and other physical properties. Studying asteroids like 2005 YU55 can help scientists understand their potential role in delivering materials to the early Earth that were essential for the origins of life.
The last time a space rock as big came as close to Earth was in 1976, although astronomers did not know about the flyby at the time. The next known approach of an asteroid this large will be in 2028.
NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.