A previously undiscovered moon crater has been provisionally named after the famous US aviator Amelia Earhart.
Partially buried under the moon's pockmarked surface, the crater is located on the Earth-facing side of the moon in a region called the Serenitatis Basin. In other words, through all of modern human history, one of the moon's largest impact craters has gone unnoticed, even though it is there, hiding in plain sight.
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The 124-mile-wide crater was discovered by scientists interpreting data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) twin satellites that was used to detect very slight gravitational anomalies below the lunar crust.
"This is one of the biggest craters on the moon, but no one knew it was there," said lead researcher Jay Melosh, of Perdue University and a member of the GRAIL science team. "Craters are named after explorers or scientists, and Amelia Earhart had not yet received this honor. She attempted a flight around the world, and we thought she deserved to make it all the way to the moon for inspiring so many future explorers and astronauts."
The GRAIL mission orbited the moon for a little under a year in 2012, but the gravitational map created has transformed our understanding of the subsurface geology of Earth's only permanent natural satellite. Consisting of two satellites, nicknamed "Ebb" and "Flow," one probe would lead and the other would follow. As they orbited close to the moon's surface, they would encounter very slight gravitational changes that directly related to density changes in the lunar crust.
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These gravity perturbations would cause one probe to accelerate (or decelerate) slightly, resulting in tiny changes in distance between the probes, which was measured to high precision. By orbiting the moon for a year, a complex gravitational anomaly map was constructed, providing scientists with an "X-ray vision" of sorts, looking deep into the moon's rock.
Using a new technique for sharpening the resolution of recorded GRAIL data to pinpoint ridges and valleys, Melosh's team was able to pick out the hidden crater rim, forming a near perfect circular signature.
"The feature turned out to be the rim of an ancient crater, but it was so big we did not even recognize it as that at first," said Rohan Sood, graduate student in Purdue's School of Aeronautics and Astronautics. "We were zoomed in on one little piece of it. We first tried to model it as a small crater, but we had to go bigger and bigger and bigger to match what the data was telling us."
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In the future, the Purdue team hope to use their analysis technique to detect the small scale structures etched out by ancient volcanic activity. Hollowed-out lava tubes, for example, could be pinpointed for future moon explorers who could use the sub-surface caverns as naturally protected habitats.
Naming a ‘hidden' crater on the moon after Earhart isn't only a fitting memorial to the American explorer, it also speaks to the mysterious circumstances that surround the aviator's, and her naviator Fred Noonan's, disappearance. In 1937, during an attempt to circumnavigate the globe in her Purdue-funded Lockheed Model 10 Electra aircraft, Earhart and Noonan disappeared and assumed lost in the region surrounding Howland Island in the central Pacific Ocean.
To this day it's not clear what happened during that fateful flight, although a part of Earhart's lost plane was identified last year.
The Perdue team will now submit their crater name to the International Astronomical Union (IAU), the official body that designates names for celestial bodies, in the hope Earhart's legacy lives on.
Source: Purdue University via Physorg.com