An asteroid about 2 kilometres in size to pass Earth tonight, about 6.3 million kilometres away from the planet.

Classed as a potentially hazardous object (PHO) - meaning it is bigger than 140 metres in size and within 5 million miles (8.04 million km) of Earth"s orbit - the asteroid known as (52768) 1998 OR2 will pass harmlessly by, with its closest approach happening 7:56pm AEST.

First spotted in 1998, the Arecibo Observatory in Puerto Rico has been tracking the space rock ever since.