The shuttle-sized asteroid 2020 SW is set to fly 13,000 miles above Earth in the next few hours, Nasa said. That means it will fly much closer than artificial satellites orbiting our planet .
The object was discovered on September 18 by a NASA-funded project in Arizona, and further observations were able to track its course and rule out any possibility of a collision with Earth.
These observations showed that it will make its closest approach on Thursday at noon UK. It will then fly away to continue its journey around the solar system. It will not return anywhere near Earth until 2041, when it will be even further away.
The asteroid is believed to be about five to ten meters wide, about the size of a "small school bus," the space agency. The size is estimated from the object's brightness, Nasa said.
It is not expected to hit Earth, scientists said. If it were to hit, it would not have time to reach the surface, as it would burst into flames and explode when it passes through the atmosphere. In fact, despite repeated suggestions that the world is threatened by asteroids, their visits are quite frequent and never pose a major danger to people on Earth.
"There are a large number of tiny asteroids like this, and several of them come as close to our planet as this one, several times each year," said Paul Chodas, director of the Center for Near-Earth Object Studies (CNEOS) at Jet Propulsion Laboratory NASA 's in Southern California .
"In reality, asteroids of this size impact our atmosphere at an average rate of about once every year or two."
Nasa is tasked with finding 90% of near-Earth asteroids that are 140 metres or larger. Such asteroids are much more dangerous than those like 2020 SW, as their larger size means they are able to pass through the atmosphere and potentially cause problems if they hit Earth.
However, the larger size makes them easier to spot. There are many more small sizes, similar to the 2020 SW, but the smaller size and lower brightness affect visibility.
"NASA's asteroid detection capabilities are constantly improving, and we now expect to find asteroids of this size just days before they come close to our planet."
