An asteroid discovered last week is due to fly past the earth at 10.30pm this evening.
The rock, which astronomers estimate is between 15 and 40 metres wide, will travel past just 39,000 miles away, which is about one fifth of the distance to the moon.
The asteroid was given the catchy name 2018 CB when it was discovered at the Catalina Sky Survey, a series of Nasa-funded telescopes in Tuscon, Arizon, last Sunday.
This GIF from Nasa shows how close the rock’s trajectory will get to the earth, relative to the moon’s orbit.
Although the asteroid is nothing to worry about, experts say this is a pretty rare occurrence.
“Although 2018 CB is quite small, it might well be larger than the asteroid that entered the atmosphere over Chelyabinsk, Russia, almost exactly five years ago, in 2013,” said Paul Chodas, manager at the Centre for Near-Earth Object Studies at Nasa’s Jet Propulsion Laboratory.
“Asteroids of this size do not often approach this close to our planet – maybe only once or twice a year.”
The shock wave following a 20-metre wide asteroid hitting the atmosphere over Chelyabinsk injured almost 1,000 people on February 15 2013.
Although 2018 CB could be up to twice the size of that one, this asteroid will be tens of thousands of miles from earth.
An asteroid is a chunk of rock orbiting the sun, left over from the formation of the solar system billions of years ago.