An asteroid twice the size of the Elizabeth Tower that houses Big Ben is to pass by Earth in a close approach on Monday.
The 430ft asteroid discovered by American astronomer Carolyn S. Shoemaker at Palomar Observatory has been designated 1994 WR12.
The asteroid then went unobserved from 1994 until it was seen again by Mauna Kea in March 2016.
1994 WR12 is set to pass Earth at a distance of 3.8 million miles on Monday - which NASA classifies as a 'close approach', reports The Mirror.
There is a a 1 in 9,090 chance it could hit Earth before 2109, which would produce a 77 megaton blast - 1.5 times as powerful as the biggest nuclear weapon on the planet.
This week NASA launched DART, Double Asteroid Redirection Test, to test a new technology to prevent future asteroid collisions.
The scheme is designed to “punch” an asteroid off course and is the first demonstration of a “kinetic impactor technique” – essentially a high-powered gun – which is designed to change the motion of an asteroid in space.
.jpg?w=600)
