Scientists stunned after discovering 'secret city' in radar image of Greenland ice sheet: 'We didn't know what it was at first'

A research plane flies over the Greenland ice sheet. A team of NASA scientists deploys advanced radar technology to map the ice dimensionally. Images of an abandoned military station emerge decades after the camp was swallowed in the frozen expanse.

These events came together in the Arctic earlier this year, resulting in intriguing new looks at what researchers call "Camp Century" or "the city under the ice."

The scientists weren't even looking for this lost city, as NASA detailed in a recent report. Instead, they were using the radar to survey the inner layers of the Greenland ice sheet, map how it interacts with the bedrock at its base, and test the technology that could help people better understand how ice sheets are responding to a warming world.

"We were looking for the bed of the ice and out pops Camp Century," recounted Alex Gardner, a project leader and NASA Jet Propulsion Laboratory scientist, per the report. "We didn't know what it was at first." 

Past surveys had located the base's remains, which appeared as a "blip" on earlier two-dimensional radar scans. On the flights in April, NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar was mounted on the aircraft. "The system looks downward and toward the side, producing maps with more dimensionality," the report explained.

"In the new data, individual structures in the secret city are visible in a way that they've never been seen before," Chad Greene, a scientist on the team, said in the story.

The U.S. Army built the camp by tunneling into ice in 1959 — aptly, during the Cold War. After it ditched the station in 1967, the camp was cryogenically entombed by the accumulation of snow and ice. It now rests at least 100 feet below the surface, according to the report.

Lost cities aside, the success of the radar technology has implications for understanding how Earth's systems are responding to temperature increases largely brought on by humans polluting the air with heat-trapping gases.  

Researchers plan to use the technology to better understand how ice sheets respond to rising temperatures, per NASA. The space agency noted that radar is "like an ultrasound for ice sheets."

The advanced UAVSAR device has already been used in various contexts — including to help assess impacts after Hurricane Milton — and scientists expect to use it in northern and southern polar regions to provide better predictions about future ice depletion and sea level rise. 

Although the scientists did not mean to record the lost camp's image on this year's mission, there has been study of when the "city" could resurface due to ice sheet melting.  

More important were the tests of the tech. "Our goal was to calibrate, validate, and understand the capabilities and limitations of UAVSAR," Greene said in the report.

"Without detailed knowledge of ice thickness, it is impossible to know how the ice sheets will respond to rapidly warming oceans and atmosphere, greatly limiting our ability to project rates of sea level rise," Gardner added. 

The report concluded that "the test flights that captured Camp Century earlier this year will enable the next generation of mapping campaigns in Greenland, Antarctica, and beyond."

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