A NASA spacecraft that is orbiting Mars has revealed that liquid water might still flow on the Red Planet. Scientists say there is a possibility that there is flowing water on Mars during the planet's warmest months. Philip Christensen, a geophysicist at Arizona State University, Tempe, focuses his attentions on Mars and Earth; spoke to reporters at NASA headquarters in Washington yesterday about a revelation that is exciting the science community. NASA scientists say the flows are not dark because they are wet, but they say there is a chance that a water flow could have changed the surface in such a way to darken the slopes' appearance.