For a brief period of time, a giant asteroid the size of an aircraft carrier, will be the closest celestial body to earth-closer even than the moon. The asteroid will pass Earth to within eight-tenths of the distance of the moon at 4.58 am IST on Wednesday, NASA has said. At the closest point, it will be within 323,469 km of Earth.

Though the space agency has classified the asteroid-called Asteroid 2005 YU55-- as a "potentially hazardous object", experts from NASA's Near Earth Object Program have said that it will not crash into the earth.

In the eventuality of it crashing into Earth, scientists say it could cause a 70-foot high tsunami within 60 miles of the crash site or a 7.0 magnitude earthquake.

The orbit and position of the asteroid, which is about 1,312 feet (400 metres) in diameter, is well known, added a senior NASA research scientist with NASA's Jet Propulsion Laboratory in Pasadena, California.

NASA plans to study the asteroid with the Goldstone radar antennas in California's Mojave Desert. Goldstone antennas are very sensitive radio telescopes used to investigate quasars, radar mapping of planets and comets.

Scientists plan to reconstruct the shape of the asteroid with a resolution as fine as 13 feet (4 meters) using the antennas. Several days of high resolution operations are also scheduled at the Arecibo Observatory in Puerto Rico.

It will also provide a rare opportunity for amateur astronomers to directly observe an asteroid with optical telescopes.

Scientists suspect YU 55 has been visiting Earth for thousands of years, but because gravitational tugs from the planets occasionally tweak its path, they cannot tell for sure how long the asteroid has been in its present orbit.

The asteroid, blacker than charcoal, is what is called a C-type asteroid that is likely made of carbon-based materials and some silicate rock.

NASA is working on a mission to return soil samples from an asteroid known as 1999 RQ36 in 2020, followed by a human mission to another asteroid in the mid-2020s.

Japan also plans to launch an asteroid sample return mission in 2018.

Meanwhile, if you are also planning to catch a glimpse of the asteroid, there's some bad news. Though it will be visible only in the northern atmosphere, it will be too dim to be seen with the naked eye. And travelling at nearly 30,000mph, it will be too fast for viewing by the Hubble Space Telescope. Even at its closest point to earth, it will be about 100 times dimmer than humans can observe.

But fret not; you can still get a glimpse of it. NASA is offering two places to take a closer look-Asteroid and Comet Watch on the main NASA site http://www.nasa.gov/mission_pages/asteroids/main/index.html , and Asteroid Watch on the Jet Propulsion Laboratory's website http://www.jpl.nasa.gov/asteroidwatch/.