An asteroid is expected to safely pass the Earth on Jan. 26. Asteroid 2004 BL86 is estimated to be about one-third of a mile in size, according to a press release from California Institute of Technology's Jet Propulsion Laboratory (JPL). Jan. 26 will be the closest any known space rock of this size will come to Earth until 2027 when asteroid 1999 AN10 will make its pass.

At its closest, 2004 BL86 is expected to be 745,000 miles from Earth.

"Monday, Jan. 26 will be the closest asteroid 2004 BL86 will get to Earth for at least the next 200 years," said Don Yeomans, who is retiring as manager of NASA's Near Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "And while it poses no threat to Earth for the foreseeable future, it's a relatively close approach by a relatively large asteroid, so it provides us a unique opportunity to observe and learn more."

Microwaves will be used to observe the space rock on its closest approach to Earth. Data and radar-generated images will be obtained by NASA's Deep Space Network antenna at Goldstone, Calif., and the Arecibo Observatory in Puerto Rico.

"When we get our radar data back the day after the flyby, we will have the first detailed images," said radar astronomer Lance Benner of JPL, the primary investigator for the Goldstone radar observations. "At present, we know almost nothing about the asteroid, so there are bound to be surprises."

A telescope from the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, N.M., first identified asteroid 2004 BL86 on Jan. 30, 2004. According to the press release, NASA's Near-Earth Object Program, also known as "Spaceguard," identifies objects such as asteroids and comets and tracks them to determine if Earth is in any danger.

Any celestial enthusiasts should be able to see the asteroid on Jan. 26 with strong binoculars or small telescopes.

"I may grab my favorite binoculars and give it a shot myself," said Yeomans. "Asteroids are something special. Not only did asteroids provide Earth with the building blocks of life and much of its water, but in the future, they will become valuable resources for mineral ores and other vital natural resources. They will also become the fueling stops for humanity as we continue to explore our solar system. There is something about asteroids that makes me want to look up."