An asteroid discovered just last week will pass closer to the Earth than the orbit of the moon this weekend, an occurrence so rare it happens only once in a decade, according to NASA.

The asteroid, called 2023 DZ2, will pass closest to the Earth on Saturday at just 175,029 kilometres away, less than half the distance to the moon (384,000 kilometres).

It was discovered last Thursday by astronomers at an observatory site at the Canary Islands, an autonomous community of Spain located off the northwestern coast of Africa.

The asteroid is around 40 metres to 90 metres in diameter, meaning its size ranges from slightly smaller than Arc de Triomphe in Paris to as tall as the Statue of Liberty in New York.

It is travelling around 7.78 kilometres a second, or around 28,000 kilometres per hour.

The NASA Asteroid Watch Twitter account flagged the asteroid’s approach, adding that it will pass us by safely.

“Astronomers with the International Asteroid Warning Network are using this close approach to learn as much as possible about 2023 DZ2 in a short time period - good practice for #PlanetaryDefense in the future if a potential asteroid threat were ever discovered,” the tweet stated.

The asteroid will pass closest to the Earth shortly before 4 p.m. EDT, according to current estimates, but EarthSky.com advises amateur astronomers hoping to catch a glimpse of the asteroid with a telescope should look early in the night on Friday.

Asteroids whiz by Earth all the time, but it’s rare for one of this size to pass so closely. Most asteroids logged as “close approaches” to Earth by the Centre for Near Earth Object Studies are either much smaller or passing much farther away, as it is still classified as a near Earth object (NEO) if it passes by within 0.2 astronomical unit, or more than 29 million kilometres away.

The next time an asteroid will pass by the Earth closer than the distance to the moon is in 2026, when an asteroid first discovered in 2013 around 15-33 metres in diameter will zip by.

In 2028, we’ll receive a close visit from 2001 WN5, an asteroid around the size of the Golden Gate Bridge at 0.93 kilometres in diameter, which last passed us in 2019. Its upcoming visit will see it pass by at just 248,332 kilometres away

And in 2029, the famous Apophis asteroid—named after the Greek term for an Egyptian god of chaos—will hurtle by at just 37,000 kilometres away, an incredibly rare occurrence that should be visible to the naked eye from Earth.

Numerous agencies have their eyes trained on the sky to keep an eye out for asteroids and other space objects that might pose a collision threat to the Earth. Although Apophis has raised eyebrows for years, a distant flyby of Earth in 2021 allowed astronomers to confirm that it wouldn’t pose any impact threat to Earth within the next century.

Last year, for a tense week in January, astronomers believed a newly discovered asteroid might be on a collision course with Earth in 2023, posing a risk level higher than had been seen in a decade. Luckily, further observations confirmed that the initial assessment of asteroid 2022 AE1’s trajectory were incorrect, and it will pass us safely this July at a distance of more than nine million kilometres away.