The close approach is set to be on January 18, at around 2.29pm. The rock, which has been named 2009 BH2, is thought to be about 88-200 metres in diameter.
The size means that it’s possible it could be much larger than the ionic bell tower Big Ben.
Indeed, on Saturday the asteroid will fly past the Earth by some 2.8 million miles.
This is considered a “close approach” by NASA.
But the rock will be joined by another asteroid.
They had, in fact, found around 19,000 of these NEOs at the start of 2019.
But the space agency stress that its NEO catalogue isn’t quite yet complete.
An impact could happen at any time, according to them.
NASA said via the Mirror: “Experts estimate that an impact of an object the size of the one that exploded over Chelyabinsk, Russia, in 2013 – approximately 55 feet (17 meters) in size – takes place once or twice a century.
“Impacts of larger objects are expected to be far less frequent (on the scale of centuries to millennia).
“However, given the current incompleteness of the NEO catalogue, an unpredicted impact – such as the Chelyabinsk event – could occur at any time.”
The NEOs have been known to come so close to our planet, agencies like NASA and the European Space Agency (ESA) need to keep a watchful eye on them.
NASA said: “Since their orbital paths often cross that of the Earth, collisions with near-Earth objects have occurred in the past and we should remain alert to the possibility of future close Earth approaches.
“It seems prudent to mount efforts to discover and study these objects, to characterise their sizes, compositions and structures and to keep an eye upon their future trajectories.”
When this happens, NASA estimates the rock will be moving at speeds of around 19.47 km per second.
This translates to speeds of about 43,553mph (70,092km/h).
It comes as an asteroid which zipped past the Earth on Tuesday went at speed off around 43,500mph.
The rock, which too went near enough to be considered a “close approach”, was sought by NASA’s asteroid tracking systems.
The NASA-tracked body did not come close enough to pose any real danger to our planet.