We might find alien life as soon as 2030, according to a new study. A lab experiment has shown that instruments on a spacecraft headed to one of the most promising worlds to find life are sensitive enough to detect a single living cell in a single ice grain.
When you think of where life beyond Earth might first turn up, you might assume Mars, or some distant exoplanet beaming messages to us. But the most promising places, surprisingly, seem to be the icy moons of gas giant planets in our own solar system. Saturn’s moon Enceladus and Jupiter’s moon Europa are both thought to contain global oceans under their icy shells, with conditions and key molecules that could support life.
To get a better idea of what conditions are like, NASA is sending a mission to one of these moons later this year. The Europa Clipper spacecraft will orbit and analyze Europa, swooping as low as 25 km (16 miles) above the surface to map its makeup and geology, gather measurements of the internal ocean, and even collect and analyze grains of ice and dust that might be sprayed out in plumes. But while it wasn’t designed to be a life-hunting mission, a new study suggests that it could discover aliens anyway.
A team led by scientists at the University of Washington and the Freie Universität Berlin conducted an experiment to see whether Europa Clipper’s instruments could detect microbes encased in ice grains. To simulate what the spacecraft will experience when collecting data from Europa’s plumes, the researchers fired a thin beam of liquid water into a vacuum, then used a laser to excite the droplets, and analyzed them with mass spectrometry to figure out what’s in them.
Standing in for the aliens was Sphingopyxis alaskensis, a common species of bacteria that thrives in cold, nutrient-poor environments like the waters off Alaska. Microbes like these are enclosed in a lipid membrane, and can form a layer of scum on the ocean’s surface, which ends up airborne in sea spray. If similar life exists in Europa’s ocean, it could potentially ride those ice grains into space, where Clipper’s mass spectrometer could detect their negatively charged fatty acids and lipids.
“We here describe a plausible scenario for how bacterial cells can, in theory, be incorporated into icy material that is formed from liquid water on Enceladus or Europa and then gets emitted into space,” said Fabian Klenner, lead author of the study. “For me, it is even more exciting to look for lipids, or for fatty acids, than to look for building blocks of DNA, and the reason is because fatty acids appear to be more stable.”
And sure enough, the team found that the instrument could detect a biological sample as small as a single cell in a single ice grain.
“For the first time we have shown that even a tiny fraction of cellular material could be identified by a mass spectrometer onboard a spacecraft,” said Klenner. “Our results give us more confidence that using upcoming instruments, we will be able to detect lifeforms similar to those on Earth, which we increasingly believe could be present on ocean-bearing moons.”
While we’re almost getting desensitized to stories of finding evidence that other planets and moons have the potential to support life, it’s pretty exciting to finally have one that could plausibly detect actual extraterrestrial life, if it’s there. We’ll be watching closely when Clipper arrives at Europa in 2030.
The research was published in the journal Science Advances.
Source: University of Washington via Eurekalert