NASA scientists have discovered that amino acids, potential signs of life, could survive near the surface of Europa and Enceladus.
Scientists have made a number of discoveries that indicate that Jupiter's icy moon Europa and Saturn's moon Enceladus contain the conditions necessary for life.
These discoveries include abundant oxygen production on Europa and liquid oceans beneath the surface of both moons.
Phosphorus, a vital element for life, has been found in plumes of ice and water ejected from the moon Enceladus.
A recent NASA experiment found that if there is life on these moons, telltale signs of it, such as organic molecules, including amino or nucleic acids, could be detected much closer to the surface than previously thought, despite incredibly shocking levels of radiation.
This is good news for any future missions that will search for signs of life that share our sun's gravity, as robotic landers won't have to dig very deep to find them.
“Based on our experiments, a safe sampling depth for amino acids on Europa is about 20 centimeters at high latitudes in the back hemisphere (the hemisphere opposite to the direction of Europa’s motion around Jupiter) in a region where the surface has not been affected much by meteorite impacts,” Alexander Pavlov, a space scientist at NASA’s Goddard Space Flight Center, said in a news release.
"Subsurface sampling is not required to detect amino acids on Enceladus, as these molecules will survive radioactive decay anywhere on the moon's surface less than a few millimeters below the surface," he added.
To find out, Pavlov and his colleagues took amino acids and mixed them with ice that was as cold as -321 degrees Fahrenheit (-196 degrees Celsius). Other samples were combined not just with ice but with silicate dust to simulate the possible presence of material from meteorites or deep within moons.
The samples were trapped in airless vials and exposed to gamma rays, a dangerous form of radiation.
Other samples tested how well amino acids would fare if they were implanted in dead bacteria, simulating the possibility of microscopic life on Enceladus and Europa.
The results showed the rate at which amino acids degrade under these conditions, and suggested that they could survive long enough to be detected by future lander missions. However, no such missions are currently scheduled for either moon.
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