Mass anomaly detected under the biggest crater of the moon

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." ".

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* This research was funded by NASA's NASA Gravity Recovery and Interior Laboratory (GRAIL) research 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.

Peter B. James, Ph.D., was part of the scientific team of three NASA missions: the Lunar Recognition Orbiter (LRO), the Gravity Recovery Laboratory and the # 1. 39; (GRAIL) and Surface, environment of space, geochemistry and telemetry of Mrcury. (MESSENGER) mission. He is the founder of the global research group at Baylor University, which is currently collaborating with the Goddard Space Flight Center to study the properties of Mercury's crust and lithosphere. Mr. James specializes in the use of spacecraft data to study the crusts and mantles of planets and moons in our solar system. He earned his PhD from the Massachusetts Institute of Technology.

Baylor University is a private Christian university and a national research institution. The University provides a dynamic campus community to more than 17,000 students by combining interdisciplinary research with an international reputation for excellence in education and a faculty commitment to teaching and learning. ;erudition. Founded in 1845 by the Republic of Texas through the efforts of Baptist pioneers, Baylor is the oldest university in Texas still in operation. Located in Waco, Baylor invites students from 50 states and more than 80 countries to study a wide range of degrees from its 12 nationally recognized academic divisions.

The College of Arts & Sciences is the oldest and largest university division of Baylor University. It comprises 25 departments and seven university centers and institutes. The more than 5,000 courses taught at the College cover areas ranging from art and theater to religion, philosophy, sociology and the natural sciences. Faculty members conduct research around the world, and undergraduate and graduate research is common in all disciplines. Visit http: // www.Baylor.edu /artsandsciences.