October 31, 2011
The planet Mercury seems placid compared to others in the solar system. But the MESSENGER spacecraft is revealing a more tumultuous past.
BOB HIRSHON (Host):
Mercury’s ancient volcanoes. I’m Bob Hirshon and this is Science Update.
Compared to other rocky planets, Mercury is fairly quiet. No winds sculpt its surface, no flowing water carves channels, and no volcanoes spew lava. But according to planetary geologist James Head at Brown University, the planet was very different billions of years ago. Head is on the science team for MESSENGER, the spacecraft now in orbit around Mercury. In the journal Science, he reports the discovery of vast fields of ancient lava and volcanic vents.
JAMES HEAD (Brown University):
These huge vents, measuring up to 25 km in length, appear to be the source of very hot lava that have rushed out, carving valleys and creating the teardrop shaped ridges in the underlying terrain.
He says similar vents once existed in what is now Northwestern United States, where the remains of huge lava flows from the Columbia River basin millions of years ago are still visible today. I’m Bob Hirshon, for AAAS, the science society.