We could discover alien life as soon as 2030, according to a new study. A laboratory experiment shows that instruments on a spacecraft traveling to one of the worlds most promising for discovering life are sensitive enough to detect individual living cells within individual ice grains.
When you think about where life beyond Earth might first appear, you might think Mars, or some distant exoplanet beaming messages to us. But surprisingly, the most promising places appear to be the icy moons of the gas giants in our solar system. Saturn's moon Enceladus and Jupiter's moon Europa are both thought to contain global oceans beneath their icy shells, with conditions and key molecules that could support life.
To better understand the conditions on Europa, NASA will send a mission to one of the moons later this year. The Europa Clipper spacecraft will orbit Europa and analyze it, swooping down at a low altitude of 25 kilometers (16 miles) above Europa's surface, mapping Europa's composition and geology, collecting measurements of Europa's internal ocean, and even collecting and analyzing ice particles and dust that may be ejected in the form of plumes. But while it wasn't designed to hunt life, a new study suggests it may be capable of spotting alien life.
A research team led by scientists from the University of Washington and Freie Universität Berlin conducted an experiment to see whether Europa Clipper's instruments could detect microorganisms encased in ice particles. To simulate what the spacecraft would experience when collecting data from Europa's plumes, the researchers fired a thin beam of liquid water into the vacuum, then excited the water droplets with a laser and analyzed them with a mass spectrometer to find out their contents.
Replacing the aliens is Sphingopyxisalaskensis, a common bacterium that grows in cold, nutrient-poor environments, like the waters off Alaska. This type of microorganism is wrapped in a lipid film and can form a layer of scum on the ocean surface, which is eventually dispersed in the air with sea fog. If similar life exists in Europa's ocean, it could potentially ride on these ice particles into space, where Clipper's mass spectrometer could detect their negatively charged fatty acids and lipids.
"We describe here a seemingly feasible scenario for how bacterial cells could theoretically be incorporated into the icy material that formed from liquid water on Enceladus or Europa and was then expelled into space," said Fabian Klenner, first author of the study. "To me, looking for lipids or fatty acids is more exciting than looking for DNA building blocks because fatty acids seem to be more stable."
The team found that the instrument could detect biological samples as small as one cell in a single ice particle.
"We have shown for the first time that even tiny fractions of cellular material can be identified by a mass spectrometer on a spacecraft," Klenner said. "Our results give us greater confidence that with upcoming instruments we will be able to detect life forms similar to those on Earth, and we are increasingly confident that these life forms may exist on satellites containing oceans."
While we've all but become numb to stories about discovering evidence that other planets and moons could potentially support life, it's still very exciting to finally have one where actual alien life, if any, can be detected. We'll be keeping an eye on Clipper when it arrives at Europa in 2030.
The research was published in the journal Science Advances.