An asteroid up to 600 m long will skim past the Earth at 5:33 pm Tuesday Korea time in a close-encounter unlikely to be matched again for another two decades. The close proximity will allow amateur star-gazers to view the asteroid with ordinary telescopes.

The Korea Astronomy and Space Science Institute and the Jet Propulsion Laboratory of the U.S. National Aeronautics and Space Administration agree that asteroid 2007 TU24, discovered Oct. 11 of last year, will be only 537,500 km away at its closest distance to Earth. That is about 1.4 times the distance between Earth and the Moon.

Donald Yeomans of NASA said the chance of a collision with Earth is slim. TU24 is thought to be up to 610 m long and 150 m wide. It will be visible with even small telescopes at an approximate apparent magnitude of 10.3 when it is closest to the planet.