NASA has found evidence of flowing water on Mars during the planet's warmest months.
The evidence of flowing water is leading NASA scientists to further wonder whether the Red Planet could support some form of life today.
While NASA's scientists have found evidence that water flowed far back in the planet's history and even evidence of frozen water now beneath Mars' surface, this is the first sign of liquid water on the planet's surface today.
The U.S. space agency said that its Mars Reconnaissance Orbiter has spotted "dark, finger-like features" that appear and extend down some Martian slopes during late spring through summer. The features fade during the planet's winter period and then reappear the spring, it said.
NASA reported on Thursday afternoon that the orbiter has imaged this phenomena repeatedly in the middle latitudes of Mars' southern hemisphere.
"NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form," said NASA Administrator Charles Bolden. "And it reaffirms Mars as an important future destination for human exploration."
NASA scientists have been studying Mars by using robotic rovers and the orbiter for some time. The key focus has long been to determine whether the planet does, or ever has, supported life.
In the summer of 2008, NASA said its work had found that Mars was once awash in water . For thousands or even millions of years, rivers, lakes and deltas coursed across the surface of Mars, the agency said at the time.
Just a few months later, NASA said the Mars Reconnaissance Orbiter had sent back information showing that it found hundreds of small fractures on the surface of the planet. At the time, NASA scientists said that the fractures directed water flows through underground sandstone millions of years ago.
The latest findings show now that water may still be flowing on Mars.
"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen, of the University of Arizona, who spoke during a NASA press conference today. Salty water is more likely to stay in a liquid form at lower temperatures than pure water.
According to NASA, the features imaged are only about a half-yard to 5 yards wide, and they are up to hundreds of yards long.