mars
Alex Lutkus/ESA01An artist’s rendering of the Mars Express orbiter, which Italian astronomers have used to detect a large body of liquid water beneath Mars’ south pole. The observations were gathered using the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument, the antenna for which is depicted here.
Davide Coero Borga/INAF/ESA02Blue radar tracks on Mars's Planum Australe show the location of what researchers believe to be a large reservoir of liquid water about 1 mile beneath Mars’ surface.
Orosei et al./ESA/NASA/JPL/ASI03A radar cross section of the southern polar layered deposits. The white band at the top is the surface echo radar. The blue spots along the basal radar echo highlight areas of bright reflectivity roughly 1 mile below the surface, which Orosei and his colleagues interpret as being caused by the presence of water.
NASA/JPL/University of Arizona04This isn’t the first time scientists have detected liquid water on Mars. In 2015 NASA scientists announced the discovery of salt deposits formed by liquid water that flows along some steep Martian slopes every summer. Researchers call these deposits, which appear in this photo of Mars’ Hale Crater as brown streaks, “recurring slope lineae.”
NASA/JPL/University of Arizona05More recurring slope lineae on Mars’ Horowitz crater. The deposits suggest that water flows seasonally, in transient trickles. Scientists aren’t sure where the water comes from, but suspects include the atmosphere, aquifers, and melting ice within the planet.
NASA/JPL/University of Arizona/USGS06Speaking of ice, astronomers have long known that Mars has frozen water locked away underground. The latest evidence of the planet’s frozen reserves came in January, when researchers announced the discovery vast quantities of clean water ice just below Mars’ surface. This false-color image shows where erosion on the planet has uncovered large, steep cross-sections of clean subterranean ice, which appears dark blue against the planet’s terrain.
NASA/JPL/University of Arizona07Mars is literally covered in evidence of its watery past, most notably in the form of valleys and basins and rivers long dry. The sediments that make up the layers in Candor Chasma, one of the red planet's largest canyons, may have been transported there by water and later eroded away by wind.
