A large crater on the side of the moon that faces Earth — the first of its kind detected in at least a century — has been named for pioneer aviator Amelia Earhart.
Purdue University scientists analyzing data from NASA's GRAIL spacecraft, which mapped the moon's gravitational field, discovered the buried crater estimated to be at least 3.9 billion years old.
The scientists announced their discovery of a giant 124 mile-wide lunar feature at the Lunar and Planetary Science Conference in Texas.
Researchers Rohan Sood, H. Jay Melosh and Loic Chappaz named the crater to honor Earhart, who was a member of the Purdue faculty as a career counselor and adviser to the Department of Aeronautics from 1935 until her death in 1937.
Earhart's plane was lost that year in the Pacific Ocean during her attempt at an around-the-world flight.
"When she was lost, she was actually flying a Purdue plane, so we wanted to recognize her in some form," Sood says.
The name is provisional and must be submitted to the International Astronomical Union for approval.
The researchers discovered the existence of the buried crater while searching GRAIL data for evidence of underground structures known as lava tubes.
Only a small portion of the crater rim is visible on the moon's surface, with most of the rest of the crater buried and detectable only by it gravity signal captured by GRAIL, Melosh says.
"This is one of the biggest craters on the moon, but no one knew it was there," says Melosh, who is 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."
In looking at the GRAIL data, an unexpected circular feature stood out, Sood explains.
"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," he says.
The researchers at first thought it was a small crater, but they had to consider a bigger and bigger model to match the data they were seeing, he says.
The visible part of the crater has always been in plain sight, Melosh says, visible with a small telescope or a good pair of binoculars.
"But no one recognized it because they didn't have the extra piece of information — the gravity field," he says.