Earth Moon It is more metal than scientists imagined.
NASA Prolific Lunar Reconnaissance Orbiter (LRO) found rich evidence of iron and titanium oxides below the moon’s surface, which may show a close connection to Earth’s early history.
Scientists have been debating how the moon formed for decades. The main theory suggests that a world the size of Mars collided with Earth billions of years ago. The colliding world shattered on impact and launched part of the proto-Earth’s surface into space. The rubble surrounded the Earth with a ring; The moon we see today is the result of that ring slowly collapsing under its own gravity.
Related: Amazing photos of the moon from NASA’s Lunar Reconnaissance Orbiter
The moon’s chemical composition, however, shows no clear evidence for that theory. The lunar highlands on the moon, visible from Earth as bright regions, have rocks with smaller amounts of metal-containing minerals relative to our planet.
That could make sense if Earth were already layered, with heavier metals sunk to the core, except that the dark moon maria planes were formed at the same time and have a greater abundance of metals than even Earth’s rocks.
The new LRO findings could explain the discrepancy. The new research is based on a device called a miniature radio frequency instrument (Mini-RF), a radar probe designed to map lunar geology, search for water ice, and test communication technologies.
The instrument scanned the terrain in the moon’s northern hemisphere for an electrical property called a dielectric constant. This constant is a number that compares the ability of a material to transmit electric fields with that of the vacuum in space.
Electric field transmission is useful for finding ice in the shadows of craters, where it is protected from the heat of the sun. But it can also identify areas where more metals, such as iron and titanium oxides, are exposed to the surface.
And scientists noted that the dielectric constant increased with the size of the crater, but only up to a point. Craters between 1 and 3 miles (2 and 5 kilometers) in diameter showed that the dielectric constant steadily increased as the craters grew larger. However, for craters 3 to 12 miles (5 to 20 km) wide, the constant remained stable.
“It was an amazing relationship that we had no reason to believe would exist,” Essam Heggy, co-investigator of the Mini-RF experiments at the University of Southern California in Los Angeles and lead author of the new research, told NASA. statement.
The team’s theory was that the first few hundred feet (or meters) of the moon’s surface have few of these oxides, but a richer source of metal is found below. Then, as meteorites collide with the lunar surface and scratch the upper layers, the metals are exposed. That kind of pattern would also explain the low levels of metal in the lunar highlands and higher abundances on the darker, lower plains closest to the moon’s subsoil.
To test their work, the researchers compared Mini-RF crater floor radar images with metal oxide maps produced by a variety of missions: LRO Wide Angle Camera, Japan Selenological Explorer and Engineering (SELENE) mission ( also called Kayuga) and NASA’s Lunar Prospector. spacecraft. SELENE and Lunar Prospector no longer work, but their file data remains.
Those observations showed that the larger craters contained more metal, according to NASA, which the researchers believe supports their hypothesis about buried metal deposits that meteorites excavate.
The results are even more intriguing in light of a puzzling phenomenon reported in 2019 by NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission on the moon. Moon’s gravity measurements suggest there is a lot of dense material that’s tens to hundreds of miles (or kilometers) below the massive South Pole-Aitken basin of the moon. GRAIL’s results, along with LRO’s new finding, suggest that metals may be more concentrated in certain regions of the moon.
The LRO results are a small step to better understand how the moon formed, as the observations show how iron and titanium oxides are distributed below the moon’s northern hemisphere. Next, the researchers will examine the craters in the southern hemisphere to see how much metal there is.
A The research-based study was published on Wednesday (July 1) in Earth Letters and Planetary Science.
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