BEIJING, Oct.30 (Xinhuanet) -- Mercury has seen an enormous amount of volcanic activity early in its history, according to scientists studying the tiny and lifeless planet.
Images from NASA's MESSENGER probe's fly-by earlier this month reveal extensive and deep lava flows on the surface, including hardened lava more than a mile deep filling a crater 60 miles in diameter.
These new images released by NASA on Wednesday show that 3.8 to 4 billion years ago, Mercury was more of a volcanic hotspot than the moon ever was, said Maria Zuber of the Massachusetts Institute of Technology, who is a co-investigator for the mission.
"That's an awful lot of volcanic material in one place for such a little planet," Zuber told a press briefing.
The pass also revealed more patches of an unknown dark, bluish material on the planet's surface.
That material was seen with NASA's first partial view of Mercury by Mariner 10 in the 1970s.
"Now we see (the dark patches) are spread all around the planet, and they appear to be excavated from depth," said Mark Robinson, an Arizona State University geologist.
This was the second of three scheduled encounters before MESSENGER enters into orbit around Mercury in 2011. It flew past Mercury on Jan. 14 and will return in September 2009.
(Agencies)
