NASA probe to observe near-Earth asteroid’s 2029 close encounter

About 5-1/2 years from now, astronomers predict, an asteroid about as wide as the Empire State Building is tall will streak through space within 20,000 miles (32,200 km) of Earth, the closest any celestial object of that size will have come to our planet in modern history. When it does, a spacecraft launched by NASA in 2016 is expected to be in position to provide a detailed examination of this rare close encounter. The mission, directed by University of Arizona scientists, is expected to yield insights into planetary formation and knowledge that could inform efforts to build a defense system against possible doomsday asteroid collisions with Earth.