Next week, a half-kilometre chunk of rock is going to provide a show for amateur and professional astronomers alike.

NASA reckons the asteroid 2004 BL86 flyby, at just three times the Earth-Moon distance, will be the nearest pass by any known object for quite some time to come. The next asteroid to pass similarly close will be 1999 A10, due in 2027.

The space agency is readying its radios to observe the pass, with Deep Space Network antennae at Goldstone, California and the Aricebo Observatory in Puerto Rico getting ready to fire observation microwaves at the rock.

The radar data will provide the first imaging of 2004 BL86, explained JPL principal investigator Lance Benner: “At present, we know almost nothing about the asteroid, so there are bound to be surprises.”

NASA also expects light reflected from the asteroid might be observable with binoculars. At its closest point to Earth, the asteroid will be 1.2 million km (745,000 miles) away.

The asteroid is currently visible to southern hemisphere sky-watchers with strong telescopes at their disposal. As it gets closer, it will become visible in the northern hemisphere.

For those without a view, the fly-by of the asteroid, also known by its number, 357439, will be live-streamed by the Slooh Observatory here, starting at 0300 US Eastern Standard Time on 27 January. ®