A big asteroid will zoom safely between Earth and the moon Saturday, a once-in-a-decade event that will be used as a training exercise for planetary defense efforts, according to the European Space Agency.
The asteroid, named 2023 DZ2, is estimated to be 40 to 70 meters (130 to 230 feet) across, roughly the size of the Parthenon, and large enough to wipe out a major city if it hit our planet.
At 7:49 p.m. GMT on Saturday, it will be less than a third of the distance between Earth and the Moon, said Richard Moissl, head of ESA’s planetary defense office.
Although it is “very close”, there is nothing to worry about, he told AFP.
Small asteroids pass by every day, but an asteroid of this size approaching so close to Earth only comes around once every 10 years or so, he added.
The asteroid will pass 175,000 kilometers (109,000 miles) from Earth at a speed of 28,000 kilometers per hour (17,400 miles per hour). The moon is about 385,000 kilometers away.
An observatory in La Palma, one of Spain’s Canary Islands, first spotted the asteroid on February 27.
Last week, the UN-endorsed International Asteroid Warning Network decided to take advantage of the extensive review, performing a “rapid characterization” of 2023 DZ2, Moissl said.
This means astronomers around the world will be analyzing the asteroid with a range of instruments, such as spectrometers and radar.
The goal is to find out how much we can learn about such an asteroid in just one week, Moissl said.
It will also serve as training on how the network would “react to a threat” that may be heading into the future, he added.
Moissl said preliminary data suggests 2023 DZ2 is “a scientifically interesting object,” indicating it could be a somewhat unusual type of asteroid. But he added that more data was needed to determine the composition of the asteroid.
The asteroid will pass Earth again in 2026, but poses no threat of impact for at least the next 100 years – that’s how well its trajectory has been calculated.
Earlier this month, a similarly sized asteroid, 2023 DW, was briefly one in 432 chance of reaching Earth on Valentine’s Day 2046.
But other calculations ruled out any possibility of an impact, which normally happens with newly discovered asteroids. Moissl said 2023 DW should now miss Earth by about 4.3 million kilometers.
Even if such an asteroid were determined to head our way, Earth is no longer defenseless.
Last year, NASA’s DART spacecraft deliberately rammed into the pyramid-sized asteroid Dimorphos, knocking it off course in the first such test of our planetary defenses.