An asteroid nicknamed “The Rock” after pro wrestler Dwayne Johnson, due to its massive size, is set to make it closest pass to Earth in 400 years this week.
The asteroid, which is travelling through space at about 33 meters per second (73 mph), is estimated to be between 650 meters and 1.4 kilometres in length.
It will make its closest approach to Earth in 400 years at 13:24 BST on April 19, at a distance of 1.1 million miles – or about 4.6 times the distance from Earth to the moon.
The asteroid will not come this close to Earth again for at least the next 500 years.
Astronomers first learned about “The Rock” (officially called 2014 JO25) three years ago, when it was observed by the Catalina Sky Survey in Arizona.
Little is known about its physical properties, but NASA claims its surface is about twice as reflective as that of the moon, meaning it will be visible from Earth.
Although there is no possibility of the asteroid colliding with our planet, this will be a very close approach for an asteroid of this size.
Small asteroids pass within this distance of Earth several times each week, but this upcoming close approach is the closest by any known asteroid of this size, or larger, in 13 years.
In September 2004, asteroid Toutatis, a 3.1-mile asteroid, approached within about four lunar distances.
The next known encounter of an asteroid of comparable size will occur in 2027 when the half-mile-wide asteroid 1999 AN10 will fly by at one lunar distance, (about 236,000 miles).
Robotic telescope service Slooh said the The Rock’s close approach was an “alarming reminder” of just how close these destructive chunks of space debris come to Earth on an almost daily basis.
“Even a 30 metre sized asteroid can cause significant damage to a major city,” said Slooh.
“While not causing an extinction level event, an impact from an asteroid the size of ‘The Rock’ would have a calamitous effect at the local and even regional level.”
NASA has described the flyby as an “outstanding opportunity” for astronomers and amateur stargazers. The asteroid should be visible with a small optical telescope for one or two nights before it moves out of range.
It added: “Astronomers plan to observe it with telescopes around the world to learn as much about it as possible.”