Volcanoes erupted on Mercury for billions of years, according to new images from the MESSENGER spacecraft. The pictures, published March 28 in Journal of Geophysical Research: Planets, show ancient vents and ash scattered within craters between 1 billion and 3.5 billion years old, suggesting that the volcanoes exploded over a long period of time.
Sustained volcanism indicates that Mercury kept volatiles — compounds with low boiling points like water — for longer than previously thought. A rich supply of volatiles suggests that Mercury escaped the cataclysmic collisions or erosion caused by the sun that researchers use to explain the planet’s oversized iron core.