An airplane-sized asteroid will pass between the Earth and moon's orbits Saturday

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NASA Small-Body Database shows the orbits of the Earth, moon and asteroid 2023 DZ2. / NASA/Screenshot by NPR

An asteroid dubbed "city killer" for its size will pass harmlessly between the moon and the Earth Saturday evening.

The asteroid 2023 DZ2 will pass at a distance of over 100,000 miles, less than half the distance between the Earth and the moon. It's about 160 feet long — about the size of an airliner. An asteroid that size could cause significant damage if it hit a populated area, hence its nickname.

"While close approaches are a regular occurrence, one by an asteroid of this size (140-310 ft) happens only about once per decade, providing a unique opportunity for science," NASA Asteroid Watch tweeted.

Astronomers from the International Asteroid Warning Network, established about 10 years ago to coordinate international responses to potential near-Earth object impact threats, will be monitoring and learning from this asteroid.

NASA Asteroid Watch called the opportunity "good practice" in case "a potential asteroid threat were ever discovered."

Near-Earth objects are asteroids or comets that pass close to the Earth's orbit, and they generally come from objects that are affected by other planets' gravity, moving them into orbits that push them close to Earth, according to the United Nations Office for Outer Space Affairs.

The European Space Agency maintains a risk list of 1,460 objects, which catalogs every object with a non-zero chance of hitting Earth over the next 100 years. Asteroid 2023 DZ2, which is in orbit around the sun, is not on the risk list.

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