Space

NASA Messenger Reveals that Solar System's Smallest Planet Mercury is Shrinking

Thomas Carannante
First Posted: Mar 17, 2014 10:54 AM EDT

NASA's Messenger spacecraft mission was launched from Cape Canaveral Air Force Station in Florida on August 3, 2004. The spacecraft's objective was to unearth the mysteries of the planet Mercury with various instruments on board.

Back in 1974 and 1975, the NASA Mariner 10 probe first discovered Mercury's shrinking surface after it provided scientists with photographs of 45% of the planet's surface. The pictures revealed that Mercury's surface was cracking and wrinkling, suggesting that it was likely shrinking. However, that technology didn't enable scientists to accurately estimate how much Mercury was shrinking.

Messenger's information has allowed scientists to discover that Mercury is about 7 kilometers smaller in diameter today than it was after its inception four billion years ago. Since entering Mercury's orbit in 2011, Messenger has photographed 100% of the planet and scientists have been able to carefully examine details about Mercury's surface.

Scientists, astronomers, professors, and others have seen the information and data provided through Messenger's pictures. They are in awe over the ridges and craters that have developed on the Mercury's surface over time.

"We see the landscape literally crumpling up," said William McKinnon, a professor at Washington University in St. Louis, in this National Geographic article. "Massive slabs of rock are sliding over one another."

"There's a structure called Enterprise Rupes in the southern hemisphere that is a single scarp system," said Dr. Paul Byrne from the Carnegie Institution, in this BBC News article. "It utterly dominates the topography and it is astounding given the diminutive size of Mercury."

Mercury is chilling and shedding heat, a process that all of the other planets undergo, but it has especially been affecting the solar system's smallest planet. The Enterprise Rupes encapsulates Mercury, and when it contracts, it completely warps its surface. The result has been the formation of cliffs and mountains that reach up to two miles high as well as ridges that extend over 1,000 miles across the planet's surface.

The Messenger mission was extended exactly a year ago today, on March 17th, 2013, which scientists are surely happy about especially in the wake of these discoveries of Mercury. Scientists believe that this information will help them understand planets beyond our solar system as well.

See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone

More on SCIENCEwr