MARS — New research from the U.S. Geological Survey has found that the mysterious streaks once thought to be proof of water on Mars are probably just sand flows. Sorry NASA! <br /> <br />According to NASA, recurring slope lineae or RSL are long, dark streaks that expand on the slopes of Mars during warmer seasons, and retract when the temperature gets colder. <br /> <br />RSL served as compelling evidence of water on Mars. It looked similar to features on Earth formed by water flows, and contained molecules that help water stay liquid. But a closer look reveals behavior that's unlike flowing water. <br /> <br />Streaks existed only on the tops of steep slopes, and all settled at the angle of repose — the maximum slope at which loose solid material can be piled without slumping. <br /> <br />Based on the findings, researchers concluded that the markings weren't created by water, but by dry grains like sand and dust that accumulate and flow down the slopes. <br /> <br />The RSL may still contain water, but probably not enough to sustain tiny microbial critters, more so human life.
