Scientists now want to seek out similar cliffs closer to the equator, hoping that the next surprise awaiting them is the discovery of ice nearer to the tropics.
This is not the first time ice has been found on Mars. The fractures and steep angles indicate that the ice is cohesive and strong, the authors say.
The ice sheets deposits were found at the geological formations with latitudes of around 55 degrees to 58 degrees located in the southern and northern hemisphere.
The ice deposits likely originated as snowfall during Mars' high-obliquity periods and have now compacted into massive, fractured, and layered ice. The deposits are exposed in cross section as relatively pure water ice, capped by a layer one to two yards (or meters) thick of ice-cemented rock and dust. The ice could shine a light on the history of the Martian climate.
The discovery is particularly exciting for future human exploration of the planet previously renowned for its dry arid landscape. The image is from the HiRISE camera on NASA's Mars Reconnaissance Orbiter, with an enhanced-color central swath between grayscale on each side. "You don't see a high-tech solution", planetary scientist Shane Byrne of the University of Arizona Lunar and Planetary Laboratory, a co-author of the study in the journal Science, said. Because the ice is only visible where surface soil has been removed, Dundas et al. say it is likely that ice near the surface is even more extensive than detected in this study.
NASA's Phoenix lander had also dug up some ice near the Martian north pole in 2008, however, it is not clear if that is part of the big sheet.
Google Assistant is now on Android Auto, because apparently it wasn't before
The pair are also working to make certain Alexa capabilities available to drivers when the vehicle is not connected to a network. Instead, when you open Google Home and tap the hamburger button in the top left, you'll see an option called Explore .
Scientists have not determined how these particular scarps initially form. Examination of some of the scarps with MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) confirmed that the bright material is frozen water.
Eight scarps, with slopes as steep as 55 degrees, reveal new information about the internal layered structure of previously detected underground ice sheets in Mars' middle latitudes, the U.S. space agency said.
The results revealed massive subsurface ice sheets on the planet extending from just below the surface to a depth of at least 100 meters (328ft).
This research benefited from coordinated use of multiple instruments on Mars orbiters, plus the longevities at Mars now exceeding 11 years for MRO and 16 years for Odyssey.
For future Mars explorers, this information will be key, the authors write.