Wrinkled Mercury's shrinking history
The planet Mercury is about 7km smaller today than when its crust first solidified over four billion years ago. The innermost world has shrunk as it has cooled over time, its surface cracking and wrinkling in the process. Scientists first recognised the phenomenon when the Mariner 10 probe whizzed by the planet in the mid-1970s. But the latest images from the US space agency's Messenger satellite have enabled researchers to refine their estimate for the amount of contraction.
Continue Reading http://www.bbc.com
Join the Discussion