Notorious as a planetary deep freeze with arid deserts, fierce dust storms and even snow at its poles, Mars apparently also has liquid water, scientists said Monday, but they could not predict whether the Red Planet's seasonal moisture is capable of supporting life.

"These exciting results are certainly encouraging," said John Grunsfeld, a former astronaut and current associate administrator for NASA's Science Mission. He and a team of scientists Monday made a powerful case for water on Mars during a news briefing and said the space agency now has renewed hope for seeking life beyond Earth.

The newly identified liquid water is exceptionally briny -- salty -- and was deduced through a series of spectrographic studies that revealed streaks on the planet that absorb light at specific wavelengths, suggestive of water. These streaks grow darker during the Martian summer and increase in size, scientists said.

Data from the Mars Reconnaissance Orbiter helped scientists conduct the investigation and to see the Red Planet not only for its water but also as a possible incubator of life.

To further substantiate their findings, the team, which included scientists from abroad, also studied specific signatures of water, such as hydration salts that were identified in four distinct Martian sites. The finding helped corroborate, they said, that liquid water trickles on Mars. Additionally, water flows on the cold and distant sphere when summer provides a warmer but still super-chilly climate.

Not everyone is convinced that Monday's announcement is the definitive word regarding liquid water on the Red Planet.

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"The evidence is certainly provocative, but there is still need for further study," said Deanne Rogers, an assistant professor of geosciences at Stony Brook University.

Two years ago, Rogers and an international team of space explorers found tantalizing evidence that water once flowed copiously on Mars. What separates Rogers' work from NASA's announcement Monday was the distinctly diverse Martian regions under investigation and sharp differences on the cosmological clock. Rogers discovered evidence of primordial water on Mars eons ago. NASA made a case that water is there now.

Both Rogers and the current team looked at minerals, albeit different ones, that form in the presence of water. Additionally, she said, it is only by digging into the subject deeper that scientists ultimately will be able to say not only that they've found water, but have determined its cycle and from where it emanates.

"They also have to determine how much water is there," Rogers said, "and water activity is a very important parameter in determining whether life can survive and proliferate."

In 2008, Scott McLennan, another Stony Brook scientist, also found evidence for ancient water on Mars.

Whether water still flows is a question that has vexed scientists for decades. Paul Fein, a retired Earth sciences teacher in the Brentwood school district, said NASA's announcement provides an intriguing new angle on understanding the Red Planet. "Mars got hit with the same comets that Earth did and comets are made primarily of water," Fein said.

He said it's not at all far-fetched that a unique Martian life form could emerge in briny water because briny shrimp thrive here.

NASA's announcement Monday coincided with the publication of the entire Martian-water investigation in the journal Nature Geosciences. In the report, scientists described the seasonal streaks as abundant. They named these grooves "recurrent slope linnae," or RSLs for short.

The RSLs are what change color from one Martian season to the next, explained Lujendra Ojha, a graduate student at Georgia Institute of Technology, the report's lead author. Ojha added that it's important to find out the water's source and to further examine its brininess.