Massive asteroid to whiz by Earth - and you'll be able to see it

Apophis is about 30 times bigger than the typical asteroid spotted flying a similar distance from our planet. (Courtesy)

A massive asteroid will fly ten times closer to the Earth than the Moon's orbit.

The 335 metre wide rock is scheduled to shoot across the sky 30,500 kilometres away from the Earth on Friday, April 13, 2029, significantly closer than the Moon's 384,400 km orbit.

Named 99942 Apophis, the large rock will first become visible to the naked eye in the night sky over the Southern Hemisphere, as it travels from the east coast to the west coast of Australia.

It will then pass across the Indian Ocean moving west, flying over Africa and the Atlantic Ocean to reach sky above the USA in less than an hour.

On Tuesday NASA scientists discussed the research opportunities that would come from such a large asteroid flying so close to Earth at the 2019 Planetary Defence Conference in Maryland.

Apophis is about 30 times bigger than the typical asteroid spotted flying a similar distance from our planet.

It will appear to shine as brightly as a star to those watching without a telescope.

"The Apophis close approach in 2029 will be an incredible opportunity for science," Marina Brozovi?, a radar scientist at Nasa's Jet Propulsion Laboratory in California told Stuff.

"We'll observe the asteroid with both optical and radar telescopes.

"With radar observations, we might be able to see surface details that are only a few metres in size."

The asteroid was first spotted in 2004 by a group of astronomers at the Kit Peak National Observatory.

Back then they predicted it had a 2.7% chance of hitting Earth.

The distance between the Apophis asteroid and Earth at the time of the asteroid's closest approach. (Courtesy)

In the years since that figure has been significantly reduced to 1 in 100,000 chance.

If an asteroid its size were to hit its impact could be devastating, with objects as small as 20m across having been known to damage environments and populations.

On March 23, 1989, the 300m asteroid 4581 Asclepius missed the Earth by 700,000 km.

If the asteroid had impacted it would have created the largest explosion in recorded history, equivalent to 20,000 megatons of TNT.