Liquid water isn't just a thing of the past for Mars -- NASA just revealed that it's also present on the planet's surface today, the New York Times reports. Scientists have detected evidence of hydrated salts on the surface of Mars, which are produced by liquid water. That leads to the conclusion that liquid water is far more prevalent on Mars than we ever thought. Alfred S. McEwan, a University of Arizona professor of planetary geology, made the discovery along with other scientists after going over images from NASA's Mars Reconnaissance Orbiter. Back in 2011, they found dark streaks (dubbed "recurrent slope linae," or R.S.L.s) alongside canyons, slopes and craters on Mars, which lengthened and disappeared seasonally. Scientists figured water might have been involved with R.S.L.'s initially, but it wasn't confirmed until they pointed a spectrometer on the Martian surface and discovered the hydrated salts.