US Immigration Focus on Life in the US: NASA announced on the 28th that it has discovered "strong" evidence of active liquid water on the surface of Mars, a necessary condition for life.
Since 2006, the Mars Reconnaissance Orbiter has repeatedly detected finger-like shadowed streaks on Martian hill slopes. NASA refers to these as "recurring slope lineae" and believes this peculiar seasonal terrain is caused by saltwater flows, but direct evidence had not been found until now.
In a new study, Lujendra Ojha and colleagues at the Georgia Institute of Technology analyzed spectral data of "recurring slope lineae" at four locations on the Martian surface obtained by the Mars Reconnaissance Orbiter. They found that the data were consistent with the spectral signatures of hydrated salt minerals formed by water flow, whereas the surrounding terrain lacked such spectral signatures of salts.
The researchers wrote in a paper published in the British journal Nature Geoscience: "'Recurring slope lineae' are the result of current water activity on Mars, and our findings strongly support this hypothesis."
A team of researchers from the United States and France published a report in the journal Nature Geoscience that day, stating that the "peculiar gullies" discovered on the Martian surface are likely traces left by high-concentration saltwater flows, and this latest discovery suggests that liquid water activity is very likely present on the surface of Mars.
When asked if the data obtained could confirm the definite presence of liquid water on the Martian surface, Alfred McEwen, a researcher from the University of Arizona on the team, stated: "I would say, almost." McEwen explained that even if there is liquid water on the Martian surface, it would not be in the form of flowing rivers, but rather as "damp soil." Researchers discovered these peculiar gullies on Martian slopes and, through data analysis, concluded that the gullies contain salt-bearing minerals, the formation of which requires water. These gullies are several hundred meters long and less than 5 meters wide, appearing only during warm seasons and disappearing as the cold season arrives. Due to the limited pixel resolution of the images captured by the Mars probe, the research team has not yet been able to determine the specific chemical composition of these minerals. For a long time, many researchers have believed that there is water on Mars, but it does not exist on the surface, but rather is buried underground in the form of ice.
The latest images released were all sent back by the Mars Reconnaissance Orbiter, which arrived at Mars in 2006 and can capture images with a maximum resolution of 0.3 meters.
According to spectral analysis conducted by instruments on the Mars Reconnaissance Orbiter, this liquid water is likely perchlorate brine, and this liquid saltwater has existed on Mars for at least 4 years.
The next goal for scientists will be to investigate whether there is any microbial life on Mars today. Jim Green, Director of NASA's Planetary Science Division, explained that the discovery of water is crucial for exploring whether there is life on Mars, but there is currently no equipment capable of verifying the existence of life on the Martian surface.
