Is there life on Mars? It’s a question us humans on Earth have been asking—and researching—for decades. Today, NASA announced some exciting new discoveries made by its Curiosity rover: organic molecules found in the rocks near Mars’ surface, and fluctuating levels of atmospheric methane.
Though there is still much to explore, this new research has let scientists know that they are on the right track in the search for evidence of life. Let our experts at the Museum help break down these exciting new findings.
First of all, what is Curiosity?
The Mars Science Laboratory, a rover called Curiosity, successfully landed on Mars on August 6, 2012, after nearly a year traveling from Earth. The size of a small car, the nuclear-powered Curiosity uses its cameras, spectrometers, radiation detectors, and other instruments on its mission to explore Mars’ Gale Crater and to climb Mt. Sharp in its center.
This rover is the first full-scale astrobiology mission to Mars since the Viking landers of 1976. Having followed the water, and found evidence of it, Curiosity now seeks to answer a big question: if Mars could have supported—or might still support—life.
What is organic matter? Why is it important that Curiosity found it?
Organic matter is the building blocks of life on Earth. These compounds contain carbon and hydrogen (and sometimes includes other elements, too, like oxygen or nitrogen).
Curiosity has detected organic molecules in the 3-billion-year-old sedimentary rock near Mars’ surface, but the source of those molecules is still unknown. What’s clear, though, is that in the distant past, Gale Crater’s water held the chemical building blocks necessary for life.
“We use Earth as a guide for looking for signs of life anywhere else,” notes geologist Sharon Purdy, of the Museum’s Center for Earth and Planetary Studies. “We look for water, we look for organics, we look for methane, all the sorts of things that are intimately tied to biological activity on this planet.”
So, why is it important that Curiosity detected methane in Mars’ atmosphere?
One of the unique things about Curiosity is that it has been able to take measurements over time. That’s key to the new methane study, which measured nearly six years’ worth of data—or, three years on Mars time.
This new data shows that the levels of methane in Mars’ atmosphere change seasonally. (Yes, Mars has seasons, too!).
What does that mean? On Earth, the majority of methane is biologically produced: humans, termites, even cow farts produce methane. Methane could be generated in other non-biological ways, but scientists can’t rule out that Mars’ methane doesn’t have biological origins.
While methane has been detected on Mars before, this new study makes it clear that the methane in the atmosphere follows a seasonal pattern. This gives scientists a new clue into understanding Mars’ atmosphere.
And why is this discovery so exciting?
For Ellen Stofan, a planetary geologist and the John and Adrienne Mars Director of the National Air and Space Museum, this discovery is the next step in answering a question that has always fascinated her: Is, or was there ever, any life on Mars?
"We have learned through our many missions that early Mars had abundant surface water, and so was possibly a place where life could have originated," said Stofan. "While we don’t know the origin of these organic molecules found by Curiosity, we know they come from that potentially habitable time period. Further investigating of these types of rocks with future missions to the Red Planet, including future human missions with geologists actually working on the surface, will help to determine whether life ever did evolve on Mars."