Gullies on Mars may have formed when the Red Planet was highly tilted on its side, triggering dramatic shifts in climate that sent water cascading down slopes to carve out ravines, a new study finds.
Scientists first discovered gullies on Mars in 2000. These strongly resembled channels that form on Earth in the Dry Valleys of Antarctica, which are carved by water from melting glaciers. As such, the Martian ravines hinted that water once flowed on Mars, and maybe still does at times.
