It's official: NASA scientists have discovered evidence of liquid water on the surface of Mars, the best evidence yet there's probably life on the Red Planet, the New York Timesreports.
In a paper published in the journal Nature Geoscience, NASA researchers "identified waterlogged molecules — salts of a type known as perchlorates — in readings from orbit," the Timesreports. "There pretty much has to have been liquid water recently present to produce the hydrated salt," Dr. Alfred McEwen told the paper.
The historic discovery was made by both NASA scientists and researchers at other U.S. institutions, including scientist Lujendra Ojha, who proposed the theory in 2011 while an undergraduate at the University of Arizona based on "dark, finger-shaped images on Mars," according to Al-Jazeera. Ojha, now a Ph.D candidate at the Georgia Institute of Technology, was the lead author on the NASA study. Here's the nitty-gritty science of how they did it, according to Al-Jazeera:
The dark streaks were originally seen by NASA's Mars Reconnaissance Orbiter travelling at low and middle latitudes in the southern hemisphere, but as temperatures spiked during summer months, the streaks appeared to be seeping downslope and faded in cold seasons. They appeared again and in the same spot year after year.
Observing this, scientists reasoned that, since Mars is about 80.5 million km further from the sun than Earth and its surface temperature rarely rises above freezing point, it was the rise in temperature during summer that triggered the shapes to appear again.
Scientists say this suggests that trapped ice inside salty particles melted and flowed down the steep slopes of Mars, creating the dark river-shaped streaks on the surface.
The dark streaks, or "slope linae," that suggest the evidence of water on Mars. (Photo: Jet Propulsion Laboratory/University of Arizona/NASA)
The space agency piqued widespread interest after announcing a "major science finding" during the Curiosity rover's ongoing exploration of the planet, declaring in a press release that it had "solved" the "Mars mystery." Many news organizations had speculated that NASA had uncovered water flows on Mars.
"While the agency hasn't elaborated, it appears the topic will be new findings from analysis of imagery from the Mars Reconnaissance Rover, confirming that salty water flowing down Martian slopes is responsible for seasonal dark streaks seen in spots on the planet's surface," CNN reported on Monday morning ahead of the announcement. The Guardian noted that, in March, NASA researchers presented evidence suggesting that an ocean "once covered a fifth of Mars’ surface and was miles deep in places."
This announcement will certainly fuel more speculation: if water is indeed still present on Mars, it's some of the best scientific evidence yet that life potentially exists in the barren deserts of the Red Planet.
“If they are announcing that they have found easily accessible, freely flowing liquid water under the surface, which is one of the theories we have been hearing for years and years, that has massive implications both for the potential for life on that planet and sustainability of humans," former NASA Mars program chief Doug McCuistion told the Boston Herald. “That would be highly enabling and might be the game-changing trigger for both finding life and hurrying up and getting people to Mars."
Nice work, NASA. Let us know when you figure out how to bring Matt Damon home.