If alien life is out there in our solar system, it's probably very small and very hard to detect, buried deep beneath the surface of an icy moon. But, rejoice alien seekers: A new test developed by scientists at NASA's Jet Propulsion Laboratory could improve our chances of spotting extraterrestrial microbes and ending our cosmic loneliness once and for all.
Jupiter's moon Europa is believed to have a warm, liquid water ocean beneath its surface. Image: NASA
Proteins, the direct expression of DNA, are a key component of life as we know it. The building blocks of proteins, called amino acids, form spontaneously around the universe, but create a distinctive pattern, or "biosignature", when life is involved in their making. Now, scientists have tailored an old-school chemistry technique to analyse those amino acid patterns, creating a tool for sniffing out alien biosignatures in just a few grams of seawater.
The method, 10,000 times more sensitive than similar techniques used by NASA's Mars Curiosity Rover, is ideally suited for a life-hunting mission to Jupiter's moon Europa, or Saturn's Enceladus, lead study author Peter Willis told Gizmodo. Willis and his colleagues have published their work in the journal Analytical Chemistry.
"The astrobiology community has recognised amino acids as uniquely interesting targets in the search for life," Willis said. "However, the technologies available for performing these analyses are lacking in terms of sensitivity and the number of amino acids that can be analysed, particularly in the area of chiral analysis."
Chiral molecules, including amino acids, are molecules that come in mirror-image versions — a "left handed" one and a "right handed" one. When amino acids form in space, scientists expect to see an equal mixture of the two versions. But here on Earth, nearly all amino acids are left handed. That's because biology requires this basic consistency in order for proteins to properly fold.
Astrobiologists expect that all protein-based life — anywhere — will similarly "choose" to produce only left handed, or only right handed, amino acids. By determining this chirality, Willis' new process offers a rapid and sensitive test for extraterrestrial biological activity. The technique can simultaneously distinguish 17 common amino acids at very low concentrations.
The researchers tested their method out on Mono Lake, a highly salty, alkaline lake in California that may be chemically similar to the globe-spanning ocean beneath Saturn's icy moon Enceladus. Eventually, they'd like to package the tool up on a spacecraft, and send it hunting for life elsewhere in our solar system.
Jonathane Lunine, an astronomer at Cornell University and co-investigator on the "Enceladus Life Finder", a proposed NASA New Frontiers-class spacecraft whose mission shares its name, said the technique was interesting. "It's not the first such instrument to operate in this way (in the lab), but no doubt it's a valuable tool in the arsenal the merits further development," he told Gizmodo.
Lunine cautioned, however, that new methods have to be tested and proven quite a bit before they're ready to be shipped off on New Frontiers adventures (the Enceladus Life Finder team is currently seeking funding for a 2025 launch). And in addition to chiral molecules, Lunine says, other indicators, like hydrocarbon patterns, will be needed to prove we've found aliens.
Still, it's always exciting to hear about scientists developing better tools to address the profound question of whether or not humans are alone. Now, let's see if we can answer that question without angering the space octopus.
Image: Aliens Wiki