Rosetta Spacecraft Spots 'Pyramid' Boulder on Comet (Photos)

'Cheops' Boulder on Comet 67P/Churyumov-Gerasimenko
A close-up of a boulder nicknamed "Cheops," which the Rosetta spacecraft imaged on the surface of comet 67P/Churyumov-Gerasimenko. (Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

The European Space Agency's Rosetta spacecraft has sent home several spectacular images that show a large pyramid-shaped boulder studding the surface of its target comet.

Rosetta mission team members have named the 82-foot-tall (25 meters) boulder on Comet 67P/Churyumov-Gerasimenko "Cheops," after the largest pyramid in Egypt's famous Giza complex. The rock is much smaller than its namesake, however, which rises 456 feet (139 m) into the Egyptian sky.

Rosetta first photographed Cheops upon arriving in orbit around Comet 67P in early August. Over the past few weeks, the probe has taken close-up pictures and several wide-angle views that highlight the rock and its surrounding boulder field.

"The surface of Cheops seems to be very craggy and irregular," said Holger Sierks, the principal investigator for Rosetta's Optical, Spectroscopic and Infrared Remote Imaging System (OSIRIS), in a statement.

"Especially intriguing are small patches on the boulder's surface displaying the same brightness and texture as the underground," added Sierks, a comet researcher with the Max Planck Institute for Solar System Research in Germany. "It looks almost as if loose dust covering the surface of the comet has settled in the boulder's cracks. But, of course, it is much too early to be sure."

Many properties of Cheops' boulder field are unknown. Scientists are examining what the rocks are made of, how dense they are and how they might have been created. It's possible that as the comet grows more active, the boulders will move around or become more visible to Rosetta's camera, team members said.

Mosaic showing a wide-angle view of comet 67P/Churyumov-Gerasimenko taken from 9.3 miles (15 km) above the surface Oct. 8, 2014. (Image credit: ESA/Rosetta/NAVCAM)

The closest pictures of Cheops were taken from an altitude of about 9.3 miles (15 kilometers), mission officials said. But on Oct. 9, Rosetta moved even closer to the comet to begin an imaging campaign that will take it just 6 miles (10 km) above the surface.

Rosetta, which launched in March 2004, will accompany Comet 67P for at least the next year to see how the icy object changes as it gets closer and closer to the sun.

The mission is the first to successfully place a probe in orbit around a comet, and it will attempt to make some more history next month. On Nov. 12, Rosetta will deploy a small lander called Philae, which will try to make the first-ever soft landing on a comet.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: