Newly obtained images from NASA's Messenger space drone have revealed previously undetected fault scarps - cliff-like landforms - on Mercury that would suggest that the planet is geologically developing.

Published in Nature Geoscience, the new NASA findings suggests that Mercury is still narrowing progress and that Earth is not anymore the only tectonically active planet in our Solar System, as astronomers previously expected.

"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," said lead author Tom Watters, Smithsonian senior scientist at the National Air and Space Museum in Washington, D.C.

Large fault wall was first discovered on Mercury way back in the mid-70s. The large scarps were formed as Mercury's interior frosty, causing the planet to contract, the crust to gap distance in between and thrust upward along faults, making some vast cliffs up to hundreds of kilometers long and or more than 1.5km high.

"For years, scientists believed that Mercury's tectonic activity was in the distant past. It's exciting to consider that this small planet - not much larger than Earth's moon - is active even today," said NASA Planetary Science Director Jim Green.

"Mercury has the potential for many more earthquakes than the moon since it's contracted a lot more than the moon has," said Watters. Seismometers set up by Apollo astronauts detected 28 moonquakes ranging from magnitude 1.5 to 5 on the Richter scale ranging between 1969 and 1977.

The scarps on Mercury also indicate that the planet is actually shrinking as it cools. While Earth's moon has been shrinking for the same reason, it might be, for the past billion years, an extreme event Mercury's shrinkage has been manifested as seen from the images NASA's Messenger reveals.