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News – Is Greenland's Ice Covering a Second Crater with a Meteorite?



FROM THIS WORLD | What's happening in space – the biggest news coming from Earth from space

Scott Sutherland
Meteorologist / Scenario of Science

Tuesday, February 12, 2019, 6:00 pm – Only a few months after the scientists announced the opening of a huge blow crater in northern Greenland, it seems they may have found a second one!

Scientists exploring the depths of Greenland's glacier layer hoped to uncover the secrets of the island lying under the ice, and seemed to find some amazing!

in
According to a new study released this week, researchers from Operation NASA's Bridge Bridge report that it has discovered a second giant crater hidden under the ice in northern Greenland.


Haiwatha Crater and this second crater are shown in this NASA computer simulation of IceBridge icebreaking radar data. Credit: NASA Scientific Screening Studio / Scott Sutherland

Detecting the 31-kilometer latitude
The Hiawatha Impact Craft was launched in November 2018. Located on the edge of the ice sheet near the coast, it was discovered by an international team of scientists using an IceBridge operation that penetrates radar data to identify what, which looks like a crater kept under a mile of ice.

It was surprising when it was uncovered, as the assumption was that shock craters in places like Greenland and Antarctica would be lost due to the heavy pressure of billions of tons of moving ice that washed them. So, finding one of these craters probably survived was unexpected, at least.

Though these findings have shown the potential that Hawaii may be a fairly young crater, according to NASA columnist Joe McGregor, he made him think if other craters may be hiding under the ice just waiting to be found.

According to NASA and the American Geophysical Union:

After discovering the first crater, McGregor checked the topographic maps of the rock under the ice of Greenland for signs of other craters. Using images on the icy surface of NASA's Terra and Aqua NASA satellites, the Moderate Separation Image Spectrum Radiometer, he soon noticed a circular pattern about 114 miles [182 km] to the southeast of the Hiawatha glacier. The same circular pattern appears in ArcticDEM, a high-resolution digital model across the Arctic, derived from commercial satellite imagery.

"I started to ask myself," Is this another crater of stroke? Do the basic data support this idea? "Said MacGregor to NASA and AGU." It helped to identify a large crater under the ice was already very exciting, but now it seemed that there could be two of them.

This newly discovered, yet unnamed, potential crater is approximately 180 kilometers southeast of the Haayavata and is slightly larger, with a visible diameter of about 35 kilometers.


Satellite view of the Hiawatha crater (top left) and the position of the new potential impact crater identified by the new study. Sincerely, MacGregor et al., Using Arctic DEM data from the University of Minnesota


A satellite view of the same region of the VIIRS instrument of the Sumatra satellite apparatus. The area of ​​the newly opened crater is underlined. Regards: NASA World / Scott Sutherland

Is this really a crater of impact?

There is still some uncertainty about this discovery, so there is currently no way to say conclusively that this
it iscrater or blow
is notcrater of impact.


NASA topographic map of the Hiawatha Crater (bottom left) and this new crater (to the right of the center). Credit: NASA Scientific Visualization Studio

Hiawatha is certainly a much better striker crater candidate. Just looked at him
appearancelikes what you would expect to see as a crater of impact, with a very obvious steep edge, flat base and center peaks. Still, however, there is a chance that Hiawa will remain from some other process or process gathering.

This new candidate is even harder to say. The surface ice function is more difficult to extract than that of Hiawatha, and depression seems to be similar to many other depressions in Greenland.

So, if it was not really a blowjob, what could it be?

"The only other circular structure that could reach that size will be a folded volcanic caldera," McGregor said in a NASA / AGU press release. "But areas with known volcanic activity in Greenland are a few hundred kilometers. Besides, the volcano must have a clear positive magnetic anomaly and we do not see it at all.

According to the study, what is this crater
doesthere is a "negative gravity anomaly", which means that the surface is suppressed (pushed down) with respect to surrounding rocks. This is characteristic of the impact craters. It is also known that negative gravity anomalies are associated with glaciers, but especially in areas that have once had glaciers long ago. Due to the presence of Greenland's current ice sheet, the island has a complete positive gravity anomaly because the mass of ice increases the area's gravity.

One of the possible reasons why this crater does not share the same "appearance" of the crack crater that has the Hawaii is that it has undergone much more atmospheric conditions and erosion as compared. According to the study, the ice over the crater is much thicker and much older than the ice of the Hiawatha glacier. This thicker ice may have eroded the crater faster, or if the crater formed earlier than the Hawaii crater, it would just have more time for erosion to take its own.

Sources:
AGU |
NASA
University of Minnesota

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