Vast, concealed glaciers discovered on MarsNovember 21st, 2008 - 2:59 pm ICT by IANS
New York, Nov 21 (IANS) Vast glaciers have been identified on Mars at much lower latitudes than discovered earlier, an encouraging sign for scientists searching for life beyond Earth. The newly discovered glaciers have survived at the lower latitudes because they are under protective blankets of rocky debris.
The discovery was made by scientists using ground-penetrating radar on NASA’s Mars Reconnaissance Orbiter, according to Science Daily.
These concealed glaciers extend for tens of miles from edges of mountains or cliffs and are up to one-half mile thick, said the scientists from the University of Texas who led the research team that made the discovery.
“Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that’s not in the polar caps. Just one of (them) is three times larger than the city of Los Angeles,” said lead author John W. Holt of the university’s Jackson School of Geosciences.
Findings of the team have been published in the latest issue of the journal Science.
“In addition to their scientific value, they could be a source of water to support future exploration of Mars,” said Holt.
The gently sloping aprons of material around taller features have puzzled scientists since NASA’s Viking orbiters revealed them in the 1970s.
The Shallow Radar instrument on the Mars Reconnaissance Orbiter provided an answer to this Martian puzzle, indicating the features contain large amounts of ice.
“These results are the smoking gun pointing to the presence of large amounts of water ice at these latitudes,” said Ali Safaeinili of NASA’s Jet Propulsion Laboratory.
The radar’s evidence for water ice comes in multiple ways. The radar echoes received by the orbiter while passing over these features indicate that radio waves pass through the apron material and reflect off a deeper surface below without significant loss in strength, as expected if the aprons are thick ice under a relatively thin covering.
The radar does not detect reflections from the interior of these deposits as would occur if they contained significant rock debris. Finally, the apparent velocity of radio waves passing through the apron is consistent with a composition of water ice.