Passage 2Scientists have found the first evidence that briny water flowed on the surface

Passage 2

Scientists have found the first evidence that briny water flowed on the surface of Mars as recently as last summer, a paper published on Monday showed, raising the possibility that the planet could support life.

Although the source and the chemistry of the water is unknown, the discovery will change scientists’ thinking about whether the planet that is most like Earth in the solar system could support present day microbial life.

The discovery was made when scientists developed a new technique to analyze chemical maps of the surface of Mars obtained by NASA’s Mars Reconnaissance Orbiter spacecraft.

They found telltale fingerprints of salts that form. only in the presence of water in narrow channels cut into cliff walls throughout the planet’s equatorial region. The slopes appear during the warm summer months on Mars, then vanish when the temperatures drop. Scientists suspected the streaks were cut by flowing water, but previously had been unable to make the measurements.

Mars Reconnaissance Orbiter makes its measurements during the hottest part of the Martian day, so scientists believed any traces of water, or fingerprints from hydrated minerals, would have evaporated.

Also, the chemical-sensing instrument on the orbiting spacecraft cannot home in on details as small as the narrow streaks, which typically are less than 16 feet wide. But Ojha and colleagues created a computer program that could scrutinizeindividual pixels. That data was then correlated with high-resolution images of the streaks. Scientists concentrated on the widest streaks and came up with a 100 percent match between their locations and detections of hydrated salts.