Hydrogen. Carbon. Oxygen. Nitrogen. Sulfur. Phosphorous. These elements account for more than 96 percent of the stuff life on Earth is made from – and all six have been found in a rock sample on Mars.
NASA scientists said Tuesday that the Curiosity rover discovered these basic building blocks of life in the very first rock it has drilled from beneath the Martian surface – along with signs that the Red Planet was once capable of hosting primitive microbes.
“It definitely has all the indications of being a habitable environment at one point in time,” Michael Meyer, lead scientist for NASA’s Mars Exploration Program, said at a news conference in Washington.
The rover’s results are filling in a picture of what increasingly appears to have been an inviting environment – low acidity, full of water, with signs of chemically complementary compounds.
“We have found a habitable environment that is so benign and is so supportive of life that probably if this water was around and you had been on the planet, you would have been able to drink it,” said John Grotzinger, lead scientist for the Mars Science Laboratory mission.
Grotzinger, a geologist at the California Institute of Technology, was quick to add that “we’re not a life-detection mission.” Curiosity’s analytical machinery isn’t built to find life’s metabolic remnants, and its cameras wouldn’t be able to resolve an image of a fossil microbe if it were staring the rover in the face, he added.
Still, the findings fired up the imaginations of NASA officials.
“I feel giddy,” said John Grunsfeld, a former astronaut who now serves as an administrator for the space agency’s Science Mission Directorate. “I have an image now of possibly a lake, a freshwater lake, on a Mars with probably a thicker atmosphere.”
The discovery fulfills the primary purpose of Curiosity’s mission just seven months after its landing on the Red Planet.
Among the first hints that Curiosity’s first drilled sample would reveal a wealth of information was its color. Rather than rusty red, the powder drilled last month showed up as shades of gray – indicating that the rock underneath, protected from the atmosphere, could still contain vital information about the planet’s mineral history.
“If there was organic material present there, it could have been preserved,” said David Blake of NASA’s Ames Research Center in Northern California.
Analysis revealed that the rock was 20 percent to 30 percent clay, which forms in the presence of water, Blake said.
That sign of water may sound like no big deal – after all, the Opportunity rover that landed on Mars in 2004 found signs of water in Meridiani Planum. But water is just part of the picture. Rock from Meridiani had magnesium and iron sulfates, salts that indicated a highly acidic environment.
The sample Curiosity drilled from a rock in Mars’ Gale Crater, on the other hand, bore calcium sulfate and halite. Those are signs of a much more neutral environment – and one far more conducive to life.
In addition, the rock lies in a former river system or a lake bed that once held enough water to host life, Grotzinger said.