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A mysterious mass of materials has been discovered under the largest crater of our solar system – the South Pole-Aitken basin of the Moon – and could contain metal from the asteroid that crashed into the Moon and formed the crater, according to a Baylor University study.
"Imagine taking a bunch of metal five times bigger than the Big Island of Hawaii and burying it underground. That's about the unexpected mass we've detected," said L & # 39; Principal author Peter B. James.
Ph.D., assistant professor of planetary geophysics at Baylor College of Arts and Sciences. The crater itself is oval in shape and is 2,000 kilometers wide – about the same distance between Waco (Texas) and Washington (DC) – and several kilometers deep. Despite its size, it can not be seen from the Earth because it is on the other side of the Moon.
The study – "Deep structure of the lunar basin of South Pole-Aitken" – is published in the journal Geophysical Research Letters.
To measure the subtle changes in gravity intensity around the moon, the researchers analyzed the spacecraft data used as part of the GRAIL mission (gravity recovery and gravity survey). 39, interior of NASA).
"When we combined this data with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered an unexpected mass of considerable mass, hundreds of kilometers under the South Pole-Aitken Basin," said James . "One of the explanations for this extra mass is that the metal of the asteroid that formed this crater is still embedded in the mantle of the moon."
The dense mass – "anything, from where it comes" – weighs the bottom of the basin more than one kilometer down, he said. Computational computer simulations of large asteroids suggest that, under the right conditions, an iron-nickel nucleus of an asteroid can be dispersed in the upper mantle (the layer between the crust and the moon's core) during an impact.
"We did the math and showed that a sufficiently dispersed core of the asteroid that had caused the impact could remain suspended under the mantle of the moon until now, rather than sink into the moon's core, "James said.
Another possibility is that the large mass is a concentration of dense oxides associated with the last stage of solidification of the ocean by lunar magma.
James said the South Pole-Aitken Basin – which is believed to have been created about 4 billion years ago – is the largest preserved crater in the solar system. More significant impacts may have occurred throughout the solar system, including on Earth, but most traces of these have been lost.
James called the basin "one of the best natural laboratories for the study of catastrophic events, an ancient process that has shaped all the planets and rocky moons that we see today." ".
This research was funded by NASA's GRAIL (NASA Gravity Recovery and Interior Laboratory) scientific team.
The co-investigators were David E. Smith, Ph.D., principal investigator of the Lunar Orbiter laser altimeter aboard the Lunar reconnaissance orbiter; Paul K. Byrne, Ph.D., North Carolina State University; Jordan D. Kendall, Ph.D., Goddard Spaceflight Center; H. Jay Melosh, Ph.D., Purdue University; and Maria T. Zuber, Ph.D., principal investigator of GRAIL.
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Material provided by Baylor University. Note: Content can be changed for style and length.
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