Humankind may soon reach evidence of extraterrestrial life in ways easier than previously thought.
A team of scientists from NASA and Pennsylvania State University has made a significant discovery while analyzing two top targets in NASA’s search for extraterrestrial life: Europa and Enceladus.
Europa and Enceladus are the two colossal moons of Jupiter and Saturn, respectively, both believed to harbor subsurface oceans conducive to life beneath their icy crusts.
The Cassini spacecraft flying close to the surface of the “moon of life” Enceladus – (Graphic: NASA).
NASA has outlined specific plans to search for life on these two moons, including the Europa Clipper mission set to launch later this year and a robotic snake designed to navigate the cracks in Enceladus’s icy shell.
However, scientists now indicate that robotic spacecraft may not necessarily need to drill down tens of kilometers to breach the ice crust and reach the subsurface ocean.
There are “treasures” buried at modest depths: Only 20 cm or even a few mm!
Europa (left) and Enceladus both have icy outer shells – (Photo: NASA).
Dr. Alexander Pavlov, a researcher at NASA’s Goddard Space Flight Center, stated: “Based on our experiments, the safe sampling depth for amino acids on Europa is nearly 20 cm in the high-latitude regions of the trailing hemisphere.”
The trailing hemisphere of Europa is the hemisphere opposite to the moon’s direction of orbit around Jupiter, an area where the surface is less affected by impacts from meteoroids.
For Enceladus, subsurface sampling is even unnecessary, as experiments indicate that amino acid molecules can survive radiation degradation at any location on the surface of this moon, or within just a few mm of the surface.
Amino acids can be produced by life or abiotic processes.
However, the presence of certain types of amino acids on Europa or Enceladus could be a potential sign of life, as they are used by terrestrial life as building blocks for proteins.
Proteins are used to create enzymes that accelerate or regulate chemical reactions and form the structures of the human body and all living organisms on Earth.
For these distant moons, amino acids and other compounds from the ocean beneath the surface may be brought to the surface through geyser activity or the slow convective movement of the ice layer.
Furthermore, experiments also suggest that NASA spacecraft, including those from other space agencies, should avoid silica-rich regions on these two moons in the future.
The degradation rate of potential organic biomolecules in silica-rich areas on both Europa and Enceladus is higher than in pure ice, making these silica-rich regions likely barren of this crucial sign of life.
