Mercury Is Geographically Active Like Earth, NASA Discovered

Mercury is geographically active much like Earth, and it is shrinking every day, NASA discovered through recent research on the closest planet to the sun.

Images from the NASA spacecraft Messenger, short for Mercury Surface, Space Environment, Geochemistry, and Ranging, found small fault scarps, which are cliff-like landforms that look like stair steps, NASA said in a statement.

Researchers said the scarps are small enough to indicate that they are young, meaning the planet is contracting. Earth was thought to be the only planet in the solar system to be tectonically active, NASA noted.

"The young age of the small scarps means that Mercury joins Earth as a tectonically active planet, with new faults likely forming today as Mercury's interior continues to cool and the planet contracts," Tom Watters, Smithsonian senior scientist at the National Air and Space Museum in Washington, D.C., and lead study author, said in the statement.

Scientists have been aware that Mercury had large rifts and canyons since Mariner 10 flew by the planet in the 1970s, the website Gizmodo noted.

"The biggest of these features is comparable to the San Andreas (fault)," Watters told Gizmodo. "They're huge. So we know Mercury had contracted, but we didn't know if that contraction had happened millions or billions of years ago, because large features with kilometers of relief will not disappear."

Over the final 18 months of the Messenger mission, from 2014 to 2015, the probe entered a low-altitude orbit over Mercury's north pole, and took pictures with a resolution of less than 20 meters per pixel, Gizmodo reported.

That is where scientists found the kilometer-sized scarp features and discovered that the older, larger fault scarps remained active.

Even though the surface temperature of Mercury is believed to be 840 degrees, Messenger discovered water ice in craters around the planet's north pole in 2012, Space.com reported. Researchers thought those regions may be permanently shaded from the sun's heat.

Mercury's southern pole could also contain icy pockets, but scientists have not been able to explore those areas because of Messenger's orbit about the planet, Space.com wrote.

Researchers previously thought Mercury shrank 4.4 miles over billions of years after the planet's birth, causing its surface to the crumple and create scarps, or cliffs that run hundreds of miles long and rise up a mile high, Space.com noted.

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