A team of researchers has discovered a meteorite impact site in Greenland that is roughly 19 miles in diameter and 1,000 feet deep.

The international group, which includes a NASA glaciologist, have worked for three years to verify the crater. The discovery was first made in 2015 by using NASA data, and has since been found to be one of the 25 largest impact craters on Earth.

NASA glaciologist Joe MacGregor says the investigation started from public information.

“NASA makes the data it collects freely available to scientists and the public all around the world,” he says “that set the stage for our Danish colleagues’ ‘Eureka’ moment.”

The crater was first spotted by the team in July 2015, while they were inspecting the topography underneath Greenland’s ice sheet using a new map. The map used data primarily gathered from Operation IceBridge, a mission by NASA to track polar ice changes. The group of researchers observed a previously unexamined circular depression beneath Hiawatha Glacier.

After using satellite imagery to find further evidence for the crater, the team sent a research plane to fly over the Hiawatha Glacier in May 2016. The research plane, sent from the Alfred Wegener Institute in Germany contained a state-of-the-art radar for ice-penetration which was provided by the University of Kansas.

MacGregor says the survey returned positive results.

“The survey exceeded all expectations and imaged the depression in stunning detail: a distinctly circular rim, central uplift, disturbed and undisturbed ice layering, and basal debris – it’s all there.”

According to the study, the crater formed less than three million years ago, making it one of the youngest craters on Earth. The team plan to continue searching for answers to the remaining questions regarding the crater including how the meteorite impact at Hiawatha Glacier could have affected the planet.

To learn more about NASA’s activities, visit: https://www.nasa.gov/earth