Imagery aids asteroid collision prediction

Images of a giant asteroid passing by Earth have been stitched together to create a 40 second video showing the rolling motion of the 5km wide behemoth.

The footage was created from 64 still radar images of the asteroid, taken Decemeber 12-13, by Nasa’s Deep Space Network antenna.

The asteroid, called 4179 Toutatis, was about 7 million kilometres from Earth when the images were taken. That’s about 18 times farther away than the Moon is.

The asteroid flies by every four years and circles the Sun in an orbit similar to Earth’s.

This close alignment makes it hazardous for Earth as on each pass it is at a different distance.

In 2004, it passed by Earth at a distance just four times farther away than the Moon.

While further away than in 2004, last week’s pass was close enough for Nasa to obtain detailed radar images of the asteroid.

The images have a resolution of 3.75 metres per pixel and reveal Toutatis to be an elongated, irregularly shaped object with multiple ridges.

Researchers studying the images said strange bright glints may indicate surface boulders.

Nasa astronomer Lance Benner said there was no chance of an impact with Earth in the near future and the new images would help to map its future path.

"We already know that Toutatis will not hit Earth for hundreds of years," Benner said.

"These new observations will allow us to predict the asteroid's trajectory even farther into the future."

The asteroid was first spotted in 1934 and its orbit was confirmed in 1989.