SUNSET: 
Many Waters May Have Mixed on Mars
New analysis shows alkaline and acidic water may have mixed beneath the Martian surface, creating an environment that could theoretically have supported life.
New Radar Data Chills Prospects of a Subglacial Lake on Mars
There could be liquid water trapped under the southern polar cap of Mars. But new observations suggest otherwise.
Does This Mars Rock Show a "Potential Biosignature"? Or Just "Wet Chemistry"?
"Leopard spots" on a Mars rock could come from life — or they could simply be a sign of a type of chemical reaction that requires water.
What Martian Gullies Mean for Water on Mars
Martian gullies have been the center of a debate about whether Mars ever has flowing water. Now, a comprehensive study examines the question.
Tsunamis Carried Boulders Across Ancient Martian Ocean
Long-ago impacts tossed up the floors of an ancient ocean on the Red Planet and carried debris to the landing site of NASA’s Viking 1 lander.
Discovery of a Recent Martian Mudslide
A geologically recent landslide on Mars appears like mudslides on Earth — but it would have required water during a time when Mars was expected to be dry.
"Liquid Water" Below Martian Surface Might Be Clay
Mysterious spots that scientists thought were subsurface lakes beneath the Martian south pole may instead be ancient clay deposits.
More Mysterious Buried Splotches on Mars Might Not be Liquid Water
Astronomers find more bright spots underneath Mars's south polar cap, but could they really be subterranean lakes?
Is an Ocean of Mars Water Trapped in the Planet’s Crust?
A new study suggests that by 3 billion years ago, most of the Red Planet’s water was locked away in minerals, and it has stayed there ever since.
Evidence Grows for Super-Salty Underground Lakes on Mars
New analysis of data from the European Space Agency's Mars Express orbiter strengthens the case for salty lakes underneath Mars's south polar cap.
The Martian Methane Mystery Continues
The most advanced instrument ever sent to Mars to study its atmosphere has failed to find any methane after months of searching.
Liquid Water on Mars! Really for Real This Time (Probably)
A radar instrument on one of the oldest operational Mars orbiters has discovered possible evidence of liquid water on Mars.
Waterlogged Salts on Mars
Scientists have confirmed that water-soaked salts likely create dark seasonal lines on Mars.
Water Once Flowed Under Mars's Surface
Fossilized wrinkles in impact craters suggest once again that water might once have flowed on Mars — this time, beneath the surface.
Freshest Mars Rock has Hints of Water
An international team of scientists has teased apart the secrets hidden inside a meteorite from Mars, including signs that the rock weathered acidic water while on the Red Planet.
Is Water Flowing on Mars?
Spacecraft images are keeping an eye on little surface flows on Mars that show up in midsummer, then fade over time. It's the strongest suggestion yet that the Red Planet can get wet.
(Drops of) Water on Mars?
Last year, as a camera aboard the Phoenix lander looked on, drops of supersalty water grew, merged, and even dripped on one of the spacecraft's landing legs.
Sleuthing Reveals Mars's Watery Past
New findings announced this week suggest that the Red Planet may have had an ancient ocean after all and that buried glaciers of ice have turned up in surprising places.
Mars Rovers Find More Evidence of Water
As Spirit and Opportunity visit new science targets, they continue to make important discoveries.
