LAWRENCE, Kan. (AP) – Researchers at the University of Kansas helped uncover what might have been a mile-wide iron asteroid that crashed in Greenland, perhaps only 12,000 years ago.
The details of the impact crater beneath the Hiawatha Glacier in the remote northwest of Greenland were recently published in Science Advances, a multidisciplinary journal.
The crater, the first of any size that lies beneath the Greenland ice sheet, is one of the 25 largest impact craters on Earth, measuring approximately 1,000 feet deep and more than 19 miles in diameter, an area a little bigger than the one that is inside the corridor of the capital of Washington. According to a NASA statement.
John Paden, co-author of the report, is an adjunct professor of electrical engineering and computer science and a researcher at the KU Center for Remote Ice Sheet Detection, or CReSIS.
While Paden said the impact of the asteroids was not as cataclysmic as the asteroid "dinosaur" that hit the Yucatan Peninsula 66 million years ago (which was 1,000 times more mbadive), it left a huge crater, which has been hidden under the ice.
Although the report on the impact crater was published earlier this month, evidence of the crater began to emerge in 2015, the Lawrence Journal-World reported.
The scientists had been collecting radar survey data in Greenland for several decades, Paden said. Meanwhile, glaciologists gathered the radar data sets to produce maps of what Greenland is like under the ice. They began to see large depressions in the form of craters, and as the site was at the edge of the ice sheet, they also saw a circular pattern, said Paden.
Researchers studying the radar data suspected that it was a crater, but they still needed more data to confirm it, according to the NASA statement.
That's where CReSIS came in.
The center was used to build an ice penetration radar system that could accurately map the area. Paden himself helped develop the signal processing software for the radar system, which was dubbed Multichannel Coherent Radar Depth Probe, or MCoRDS.
Carl Leuschen, badociate professor of electrical engineering and computer science and director of CReSIS, also participated in the project; Rich Hale, president of the department of aerospace engineering of KU and badociate director of CReSIS; and Fernando Rodríguez Morales, professor of electrical engineering and computer science.
In May 2016, the KU team went to Greenland to tour the area. Rodríguez-Morales and Paden went to the field and conducted surveys on the impact crater site.
"Just being part of it was an incredible series of events," Paden said.
"The crater is located at a remote location in the far north of Greenland," he said. "We could hardly go because of the weather, we waited two weeks."
The fog was very bad most of the time they were in Greenland, which meant they could not fly. However, the weather improved towards the end of the trip, and finally they obtained authorization to operate outside the Thule Air Base. They were able to make three days of flights.
"That was the exciting part of the trip," Paden said. "I did not think we would get data."
The crater was buried under the ice and it was difficult to see it from the plane. However, when the plane pbaded over the edge where the ice bottom once falls over the crater, they could see it.
"There was a visible advantage in the ice sheet, it was very unusual, almost a perfect semicircle," Paden said. "Once NASA scientist Joe MacGregor pointed out to me, it seemed obvious that it was a crater, and the detailed survey confirmed it."
MacGregor co-directed the research project with the Danish scientist Kurt Kjaer.
"We were able to put at rest (it) definitely had an impact crater shape," Paden said. "The image was so clear, there was nothing that we have seen."
At the launch of NASA, Kjaer said that "the crater is exceptionally well preserved, and that is surprising because the ice of the glacier is an incredibly efficient erosive agent that would have quickly eliminated the traces of the impact."
Kjaer said the condition of the crater indicates that the impact could have occurred towards the end of the last ice age, which would place the resulting crater among the youngest on the planet.
Previous studies have shown that large impacts can profoundly affect Earth's climate, with important consequences for life on Earth at that time. The international research team plans to continue its work in this area, addressing the pending questions about when and how the impact of the meteorite on the Hiawatha glacier affected the planet.