London: A half-km wide asteroid which streaks past the Earth next week could provide clues about how the planet was formed.
The space rock, which is known as "2005 YU55" and is as big as an aircraft carrier, will pass earth within 320,000 km Nov 8.
The asteroid, in orbit around the Sun, has not been this close to the Earth in 200 years and will come closer to the planet than any other asteroid of its size in the past 35 years, the Telegraph reports.
The last time a similarly large rock passed by at such a short distance was in 1976 - but it went largely unnoticed because everybody - the National Aeronautics and Space Administration (NASA) of the US included - failed to notice it.
Now, astronomers who missed that event will have another chance of a close encounter as the gigantic object whizzes by the earth next Tuesday.
It will not be visible to the naked eye but amateur astronomers stand a good chance of catching a glimpse of it provided they have a telescope at least six inches in diameter.
NASA scientists, who have officially classified the asteroid as a "near-earth object", will use a radar telescope to analyse exactly what it is made of and get a better idea where it comes from.
A spokesman said: "We hope to obtain images that should reveal a wealth of detail about the asteroid`s surface features, shape, dimensions and other physical properties."