NASA just keeps finding Earth-like features on Mars. After water ice and snow, the space agency has now uncovered water-ice glaciers hidden under "thin layers of crustal debris" near the red planet's equator. Scientific American elaborates:
The findings, published today in Science, come from the [Mars Reconnaissance Orbiter]'s shallow radar, or SHARAD, which is able to penetrate the surface and examine what lies beneath. In this case, SHARAD indicated that two long-visible mid-latitude features, one of which is roughly three times the size of Los Angeles, are almost completely composed of water ice. (The suspect glaciers are covered by debris that obscures them but also insulates the ice from sublimating into water vapor, much as street grit forms an opaque, protective blanket over roadside snowbanks.)
But wait—how did glaciers end up at the planet's equator? The authors of the study attribute that to Mars' lack of a large moon like ours, which makes its axial tilt (and therefore climate) fluctuate more heavily.
The location of the glaciers may turn out to our advantage if we ever send a manned mission to Mars, too. According to Victor Baker of the University of Arizona, the combination of abundant sunlight and ice at lower latitudes could allow a mission to produce oxygen and hydrogen locally. "Mars doesn't have much free oxygen, and people need that to breathe. And hydrogen is a great fuel for getting back from Mars," he points out.