At 54 pounds, this Mars rock is largest on Earth. It could sell at auction for $4 million

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A chunk of the Martian surface that made an unlikely interplanetary voyage to Earth will soon be available to the highest bidder.

And for a few million dollars, it could be yours.

Sotheby's, a British-founded broker based in New York City, will soon auction off a cosmic item it's billing as the largest Martian meteorite ever found on Earth. Of course, such a distinction is expected to also fetch a high price tag.

Here's everything to know about the large, valuable Mars rock.

Mars rock could sell for $4 million at Sotheby's auction in New York

The large space rock, which has the scientific name of NWA 16788, had its Martian origins validated by the Meteoritical Society, which included it in its Meteoritical Bulletin, the global journal of record for meteor-related science.

Sotheby's, one of the oldest and largest fine auctioneers of art and collectibles in the world, will auction off the meteorite, along with more than 100 other items, Wednesday, July 16, at its New York City headquarters.

Marketed by Sotheby's as "the largest Martian meteorite ever found on Earth," the cosmic object could sell for up to $4 million, making it the most valuable meteorite ever offered at auction.

"NWA 16788 is a discovery of extraordinary significance," Cassandra Hatton, vice chairman of science and natural history for Sotheby’s, said in a statement. "Weathered by its journey through space and time, its immense size and unmistakable red color sets it apart as a once-in-a-generation find."

Martian dust devil caught by NASA rover

A Martian dust devil was captured rolling across the planet's surface by NASA's Perseverance Mars rover.

NASA/JPL-Caltech/LANL/CNES/CNRS/INTA-CSIC/Space Science Institute/ISAE-Supaero/University of Arizona

What are meteorites?

Rocks in space are known as meteoroids. If those space rocks enter Earth's atmosphere, they become meteors that streak across the sky in events colloquially referred to as "shooting stars."

Meteors – or fragments of them – that survive their atmospheric trip and land on the surface without burning up become meteorites, according to NASA.

Martian meteorite, or Mars rock, is largest on Earth: How big is it?

The Martian meteorite is 54 pounds, or about the weight of a standard bag of cement.

Measuring nearly 15 inches by 11 inches by 6 inches, the space rock is approximately 70% larger than the next largest piece of Mars found on Earth. In fact, it is so large that it represents approximately 6.5% of all Martian material ever found on Earth.

How did Martian space rock get to Earth?

NWA 16788 was discovered Nov. 16, 2023, by a meteorite hunter in Niger’s remote Agadez region in the Sahara Desert.

Featuring an unmistakable reddish Martian hue, NWA 16788’s internal composition suggests it was blasted from the surface of Mars by a powerful asteroid strike. Intense enough to turn some of the meteorite’s minerals into glass, the asteroid strike sent the rock hurtling through space, where it miraculously made it through Earth's atmosphere without burning up, Sotheby's said in an auction house video.

Because the meteorite shows signs of minimal Earthly weathering, and its chemical makeup has not significantly changed, experts believe it reached our planet in recent years.

On a planet mostly covered in water, discovering meteorites on land is incredibly rare.

And Mars meteorites are even more elusive on Earth. Of the more than 77,000 officially recognized meteorites, only 400 are Martian meteorites, according to Sotheby's.

The meteorite was previously on exhibit at the Italian Space Agency in Rome and at a private gallery in Arezzo, Italy, in Tuscany, before it landed in Sotheby's auction.

Eric Lagatta is the Space Connect reporter for the Paste BN Network. Reach him at elagatta@gannett.com