A few months after revealing an impact crater the size of Washington, DC, buried under the ice of northwest Greenland, a team of scientists discovered that it has company: a great depression 180 kilometers away that can also be an asteroid or a impact crater of a comet.
Several years ago, after researchers discovered the first crater that was hidden by the naked eye under the Greenland Hiawatha glacier, they began to track satellite records and radar profiles that penetrate the ice in search of other circular deformations. Profiles of NASA's IceBridge research flights revealed a 36-kilometer-wide, bowl-shaped depression surrounded by an edge, with a collection of raised peaks in the center that resemble the elevation to the left after that an asteroid or comet hits the surface of the Earth.
But unlike the Hiawatha crater, the basin has not yet thrown quartz crystals in shock, considered the best evidence of an extraterrestrial impact. The basin seems eroded and filled with ice older than the Hiawatha crater, which suggests that if it is a crater, it probably comes from a different impact, the researchers write this week. Geophysical research letters.
While this may seem an unlikely coincidence, other pairs of unrelated impacts have been found in Ukraine and Canada. And the cosmic collision rate needed to achieve such a coincidence is possible, given recent studies showing an increase in the bombardment of the Earth by extraterrestrial objects in the last 300 million years.