Gallery: Field notes from the hunt for life on Mars

May 22, 2015 /

If you’re looking for life on Mars, go to northeastern Chile. Turns out, a place like the Licancabur volcano, where the atmosphere is thin, ultraviolet radiation is high and the temperature is varied, has conditions similar to Mars 3.5 billion years ago, right before scientists think the red planet became inhospitable to life. That makes it the perfect lab for SETI researcher Nathalie Cabrol (TED Talk: How Mars might hold the secret to the origin of life), who goes there to try and figure out how life can form despite impossibly harsh conditions. Here, Cabrol shares thoughts and photos from the nine expeditions she and her team have made to Chile since 2002.

Life at base camp

An expedition to Licancabur lasts up to six weeks, and base camp is at a former military building some 17,000 feet above sea level on the Chilean side of the Andean Plateau. The altitude is brutal: “Our first night, I literally thought I was going to die,” says Cabrol.

Climb to acclimatize

For three days, Cabrol and her team, made up of scientists — including her planetary geologist husband, Edmond Grin — doctors and a logistics crew, stay at base camp and work at the lower lakes to collect samples and run experiments. Then for a few more days they’ll travel to and from mid-camp, at 18,000 feet, before heading to the 20,000-foot-summit.

Sleep on the side of a volcano

The team makes its own mid-camp by carving a five-by-two-meter terrace on the side of the volcano, which has a 42-degree slope in most places. “You just pray when you go to sleep that night there won’t be any earthquakes,” says Cabrol. “If there are, you’re dead.”

Look for life

The summit camp is on the outer rim of volcano; the real work is done at the caldera, the crater at the top, which holds this lake. “We’ve been working there many years,” says Cabrol, “It’s always the same feeling when I arrive there: it’s a pure jewel.” The team’s primary goal is to study how life has survived and adapted in these extreme conditions. The hope is that information collected here will inform future missions to Mars — which in turn may give us clues as to how life wound up on Earth in the first place.

Dive at altitude

Samples are collected from around — and in — the lake, which is up to sixteen feet deep. This picture shows Cabrol diving using a rebreather, which recycles exhaled air by removing the carbon dioxide and mixing what’s left with more pure oxygen. In 2006, the team broke the world record for scuba diving at this elevation.

The ghost of 3.5-billion-year-old organisms

A bit about the science: These mounds are stromatolites, formed by the interaction of microorganisms with the atmosphere. Stromatolites tell us about the very first organisms, fossilized 3.5 billion years ago. When Cabrol first started this project, her hypothesis was that conditions on Mars were so harsh that life didn’t have a chance. So when she saw these mounds, she says, she was stunned. “I realized, not only had life been here in the past — it’s absolutely everywhere,” says Cabrol. “I sat down on one of those mounds, and said to my husband, ‘Where do we start?’”

An experiment on extreme life

For this experiment, the researchers left UV-transparent and UV-opaque plastic boxes in the field for several years. The goal: to compare how the microorganisms living underneath the boxes adapt to either extreme or low solar radiation.

How to survive in high ultraviolet conditions

This is the summit lake of a different volcano in Chile called Aguas Calientes. The water appears red because of the microscopic algae that developed special pigments to survive the severe ultraviolet radiation of this region. Generally a UV index of 11 is considered extreme — here it can reach 43. Cabrol and team are dressed head to toe to guard against the high UV, and to keep warm. (Temperatures can plunge to -18 degrees celsius at night.)

An ongoing road to discovery

In the next phase of her research, Cabrol will try to identify biosignatures, the physical and chemical conditions that show conclusively that life is present in these extreme conditions. This will then support NASA’s Mars 2020 mission on which researchers will study Martian rocks and sediments and search for these same biosignatures. Says Cabrol, “I think there’s a great chance we will wind up finding our own origin out there five years from now.”

All photos courtesy of High Lakes Project/SETI Institute/NASA Astrobiology Institute.