Hope you’re not bored of stories about water ice on Mars: Now that scientists have found it, they can’t seem to stop finding it. Just a few months after the dear, departed Mars Phoenix Lander made history by touching and analyzing water ice beneath the soil near the Martian north pole, researchers using NASA‘s Mars Reconnaissance Orbiter have discovered massive glaciers near the equator. The glaciers, buried under rocky debris, are said to be more than three times the size of Los Angeles, up to half a mile thick and skirt the edges of mountains and cliffs [Telegraph].

The glaciers’ presence means that rovers on future scientific missions won’t have to land at the freezing cold poles to study the planet’s ice. The glaciers could even prove helpful as a source of drinkable water to future astronauts exploring Mars. “This says there may be samples of ice within our reach,” [researcher Jim] Head said. “If we’re thinking ahead to human exploration of Mars, it means we could go to some of these places and actually have water ice there” [Wired News]. Astronauts could also make hydrogen fuel from the ice, researchers say.

Researchers were somewhat surprised to encounter ice so close to the equator, but say it must have formed millions of years ago during an ice age, when the planet tilted on its axis and ice sheets may have spread over the mid-latitudes. Writing in Science [subscription required], researchers explain that the lingering glaciers were then covered by a blanket of debris. Without the protective covering of dirt, all of the glacier ice would probably have sublimated into Mars’ thin atmosphere, erasing this record of past climate change [Science News]. There’s also a chance that the ice could have preserved microbial life from an earlier era.

The hidden glaciers look like gentle slopes around the edges of steeper hills and were first spotted by the Viking spacecraft in the 1970s, but earlier researchers thought the landforms were mostly rock. However, study coauthor Jim Head had studied the debris-covered glaciers in Antarctica’s Dry Valleys, and says that the earthly landforms made him want to take a second look at the Martian structures. The team used a radar on NASA’s Mars Reconnaissance Orbiter, and the radar echoes received back indicated that radio waves passed through the overlying debris material and reflected off a deeper surface below without losing much strength — the expected signal for thick ice covered by a thin layer of debris [SPACE.com].

Image: ESA/DLR/FU Berlin