Agence France-PresseMarch 16, 2014 14:30
Beneath its Sun-scorched exterior, the planet Mercury is cooling, which is causing it to shrink ever so slightly, scientists said Sunday.
Over the last 3.8 billion years, the planet has shrunk by up to 14 kilometers (8.8 miles) to reach its present diameter of 4,800 km (3,032 miles), they said.
Mercury, like Earth, is believed to have a superhot metallic core.
But unlike Earth, it has no tectonic plates which bump and jostle and slide in response to the stress that heat loss causes on the planet's crust.