NASA is exploring the possibility of discovering biosignatures—complex organic molecules like amino acids and nucleic acids—beneath the icy surfaces of Europa and Enceladus. These moons of Jupiter and Saturn, respectively, are prime candidates for hosting life, with several studies suggesting they may contain vast liquid water oceans beneath their frozen exteriors.
Future robotic missions are anticipated to dig into the surfaces of these moons to uncover any biosignatures that may be trapped in the ice. These molecules are unlikely to survive on the surface due to the intense radiation from the sun, which can destroy complex organic compounds.
For Europa, the study indicates that a depth of about 8 inches (20 centimeters) might be needed to find intact amino acids, particularly in the less disturbed regions of the moon. Conversely, on Enceladus, these molecules could be present just beneath the surface, and might even be detectable without direct sampling, thanks to the moon’s plumes which could be analyzed by orbiting spacecraft.
Despite the harsh conditions—extreme cold, lack of atmosphere, and constant bombardment by radiation and cosmic rays—the potential presence of liquid water oceans beneath the ice, heated by geothermal processes, continues to drive interest in these moons.
