Researchers from the University of Kansas have been able to uncover what could have been an iron asteroid that collided with Greenland perhaps 12,000 years ago.
Details of the impact crater under the glacier Hiawatha in northwestern Greenland have recently been published in the journal Science, a multidisciplinary journal.
The crater – the first of any size below Greenland's ice sheet – is one of the 25 largest craters on Earth, about 1,000 meters high and more than 9 kilometers deep, slightly larger than the Washington DC highway, According to NASA's release.
John Fadan, co-author of the report, is an associate professor of electrical engineering and computer science and a researcher at the Ice Sheet Remote Sensing Center, or CReSIS.
While Padan said the asteroid effect was not as deadly as the "dinosaur" that hit the Yucatan peninsula some 66 million years ago (1,000 times more massive), it left a huge crater hidden under ice.
Although the report on the impact crater was published only earlier this month, the evidence for the crater began to surface in 2015, according to the Lawrence Journal.
Scientists have collected data from radar in Greenland for several decades, Padan said.In the meantime, Glaciologists put the radar data sounds together to produce maps of what Greenland is like under ice. They began to see large depressions like a crater, and because the site was on the edge of the ice, they also saw a circular pattern, Padan said.
The researchers, who studied the radar data, suspected it was a crater, but they still need more data to confirm it, according to NASA data.
This is where CReSIS came from.
The center was built to build an ice-penetrating radar system that would allow accurate mapping of the terrain, and Padan himself helped develop the signal processing software for the radar system, which was called the Multi-Channel Multi-Channel Radar Depth (MCoRDS).
Also involved in the project were Carl Leuschen, professor of electrical engineering and computer science and director of CReSIS; Ritz Heil, Chair of the Department of Aerospace Engineering of KUSIS, and Fernando Rodriguez-Morales, Professor of Electrical Engineering and Computer Science.
In May 2016, the KU team went to Greenland to surround the area. Rodriguez-Morales and Padan entered the field and conducted surveys on the crater site.
"Just being part of it was an amazing series of events," Padan said.
"The crater is located at a remote location in the far north of Greenland," he said. "We could hardly walk because of the weather, we waited two weeks."
The mist was very bad for most of the time they were in Greenland, which meant they could not make any flight. However, the weather has improved toward the tail end of the trip, and they finally have permission to operate from Thule Air Base. They could do three days' flight.
"That was the exciting part of the trip," Padan said. "I did not think we'd get data."
The crater was buried under the ice, and hard to see from the plane. However, when the plane went on a rim where the ice dropped once over the crater, they could see it.
"There was a prominent edge on the ice – it was very unusual, almost a half-circle perfect," Padan said. "Once NASA scientist George McGregor pointed it out, it seems clear to me that it's a crater, and the detailed survey is that."
MacGregor co-led the research project with the Danish scientist Kurt Kjaer.
"We could rest (because) it was definitely shaped like an impact crater," Padan said. "The images were so clear: there was no such thing as we saw."
In an edition of NASA, Kjaer noted that "the crater is exceptionally well preserved, and it is surprising that ice ice is a very elusive and effective agent that would quickly remove traces of impact."
Kjaer said that the condition of the crater indicates the impact may have even occurred towards the end of the last ice age, which will place the crater formed among the youngest on Earth.
Previous studies have shown great effects can affect the climate of the Earth, with serious consequences for life on Earth at that time. The international research team plans to continue its work in this field, addressing the remaining questions about when and how the impact of the meteorite in the glacier Hiawatha affected the planet.