An asteroid which was first tracked by Nasa just three days ago will skim past Earth and the Moon in an astronomical near-miss today (28 December).
The space rock – which will be travelling at 21,363 mph when it makes its closest approach to earth at 4.56pm on December 28 – measures between seven and 15 metres (22.6 to 49 feet) in diameter.
The asteroid -named 2017 YZ4 – had been completely invisible to astronomers until Christmas Day when it was first tracked.
It will pass between the Earth and the Moon at a distance of just 139,433 miles – close enough to be considered a near miss by astronomers.
NASA considers and monitors anything which comes within six million miles of our planet as a near earth asteroid.
It was first spotted by the Arizona-based Mount Lemmon Survey Observatory.
Although, relatively small, if it did impact Earth, it could cause a fair bit of devastation.
In 2013, another unknown rock came from nowhere to explode in the sky above Chelyabinsk, Russia.
The blast which had the force of 500,000 tonnes of TNT shattered glass on hundreds of buildings. More than 1,000 people were injured.
A NASA spokesman said: “This is the first known asteroid to flyby Earth within one lunar distance since two such asteroids flew past us 35 minutes apart on November 21, and the 52nd this year.
“As of December 24, there are 17,495 known Near-Earth Objects (NEOs) around our planet; 17,389 are asteroids.
“This year, we discovered 1,985 new near Earth asteroids. There were 1888 such objects discovered in 2016 and 1,571 in 2015.”