Exactly five years and one month ago, the Mars Curiosity rover successfully landed in Gale Crater despite only 40% odds of succeeding. Since then, NASA’s plucky little rover has been seeking evidence that the area — which is 3.8 billion years old — could have been habitable at some point in the past, and it’s found plenty of that evidence, including water-transported gravel (suggesting a once-flowing river), a surprising amount of water (of the soil tested, 2% of it was ice), and methane (which is usually produced by living microbes). Although actual life forms or fossils thereof haven’t been found, the newest discovery lends even more credence to the possibility life may have existed on Mars in the past.
Now boron has been discovered at the Murray Buttes in Gale Crater, as detailed in a paper published Tuesday in Geophysical Research Letters. Lead author Patrick Gasda of the Los Alamos National Laboratory explained why boron is a sign of potential life. “Because borates [Ed.- boron dissolved in water] may play an important role in making RNA — one of the building blocks of life — finding boron on Mars further opens the possibility that life could have once arisen on the planet,” he said. “Borates are one possible bridge from simple organic molecules to RNA. Without RNA, you have no life. The presence of boron tells us that, if organics were present on Mars, these chemical reactions could have occurred.”
Boron dissolved it water helps stabilize sugars like ribose long enough for them to build RNA. “Essentially,” said Gasda, “this tells us that the conditions from which life could have potentially grown may have existed on ancient Mars.”
Where the boron was detected — in calcium sulfate mineral veins — suggests Gale Crater once had habitable groundwater with neutral-to-alkaline pH and temperatures between 0-60°C (32-140°F). It seems the more Curiosity digs, the more signs of life it finds. It’s all just one more reason to get our asses to Mars.