Posted: Thu, Dec 23, 2004, 12:29 PM ET (1729 GMT)
Images by ESA's Mars Express spacecraft suggest that volcanic activity may still be taking place on Mars. In a paper published in Thursday's issue of the journal Nature, planetary scientists said high-resolution stereo images taken by the orbiter revealed lava flows without any evidence of impact craters. The lack of craters implies that the flows must be very young, likely no more than about two million years old. Scientists believe that volcanic activity, once thought to have died out hundreds of millions or even billions of years ago, may still be possible on the planet today, taken place during very brief, intermittent periods. The Mars Express images also reveal evidence of glacial activity within the last few million years on the slopes of Olympus Mons, the planet's tallest mountain.

Related Links:

•  SPACE.com article
•  AP article
•  The Guardian article
•  USA Today article