Mountains on Saturn moon may have come from space.
A mysterious mountain ridge ringing the equator of Saturn's
moon lapetus may be a load of space rubble. Ever since the Cassini
spacecraft spied the jagged belt wrapped around lapetus' middle in
2004, scientists have debated the ridge's origin. Some think
volcanoes shoved it up from beneath the moon's surface or that
tectonic activity created the range. Others think that the towering
mountains, which may reach more than twice the height of Mount Everest,
could be remnants of rings that once orbited the moon. The ring theory
got a boost from an analysis of Cassini images by Erika Lopez Garcia of
Brown University in Providence, R.I., and colleagues, lapetus'
ridge has steep slopes, a clue that the mountains may have formed as
debris rained down on the moon and piled high on the surface, the team
reports April 9 at arXiv.org.