An asteroid the size of a blue whale is getting closer to Earth

Another asteroid is hurtling towards us, but scientists believe we are safe.

Named 2018 CB, the space rock will pass by on Friday afternoon, but will miss Earth by just 39,000 miles (64,000 kilometres). That’s just one-fifth of the distance to the moon.

And if you were wondering how big the asteroid is, Paul Chodas, manager at NASA’s Center for Near-Earth Object in California, said it's about the size of the one that exploded over Russia five years ago – between 50 and 130 feet wide.

You may remember how the world looked on in shock as video footage and photos of what looked like an incoming meteor emerged from Chelyabinsk, Russia on 15 February 2013.

Although there's absolutely no concern 2018 CB will collide with our planet, Mr Chodas said asteroids of this size don’t usually come so close:

...it’s a reminder that asteroids can pass very close to our planet and it’s important that we find these objects when they get close.

And it’s already the second time this week an asteroid has come in close proximity to Earth

One passed within 114,000 miles (184,000 kilometers) of the planet on Tuesday, slightly more than halfway to the moon.

Other recent asteroids that came hurtling towards Earth.

The small asteroids 2008 TC3 and 2014 AA were detected before they entered the Earth’s atmosphere.

The 4.1 metre (13 ft) diameter 2008 TC3 entered our atmosphere in 7 October 2008. It exploded at an estimated 37 kilometres (23 miles) above the Nubian Desert in Sudan. About 600 meteorites were later recovered.

And the smaller 2014 AA asteroid was 2-4 metres in diameter and struck Earth on 2 January 2014. It entered the atmosphere about 21 hours after it was detected by Richard Kowalski of the Catalina Sky Survey in Arizona.

The Minor Planet Center announced it likely impacted on arc extending from Central America to East Africa, but was unlikely to have “survived atmospheric entry intact".

A mega space rock is predicted to pass Earth in 2029, just one tenth of the distance between Earth and the moon.

The asteroid, named Apophis, is estimated to be about 1,000 feet in diameter according to NASA. Upon its detection in 2004, it was estimated to have 2.7 per cent chance of hitting our planet but later measurements showed there was no impact risk.