An asteroid this size coming so close to Earth is a once-in-a-decade event, although a collision with the planet is not expected. The journey offers astronomers a prime opportunity to study a space rock.

A large asteroid is scheduled to safely zip between Earth and the moon later on Saturday, in what is considered a once-in-a-decade event.

The asteroid, named 2023 DZ2, is big enough to wipe out a large city if it collides with Earth. It is estimated to be 40 to 70 meters (130 to 230 feet) wide.

2023 DZ2 will come at 1949 GMT within a third of the distance from the Earth to the moon, according to Richard Moissl, the head of the European Space Agency's planetary defense office.

"There is no chance of this 'city killer' striking Earth, but its close approach offers a great opportunity for observations," Moissl said in a statement.

Why is this asteroid special?

Asteroid flybys are a common occurrence. However, the chance of an asteroid so big to come so close to earth is once in a decade, NASA said.

The asteroid's trip will offer astronomers the chance to study a space rock from merely over 100,000 miles (168,000 kilometers) away, less than half the distance between the Earth and the moon.

2023 DZ2 should therefore be visible through binoculars and small telescopes.

The asteroid was first spotted on February 27 by an observatory in La Palma, one of the Canary Islands. It's not due back our way again until 2026.

rmt/wd (AFP, AP)

DW