A new study mapping the radiation levels on Europa reveals the icy moon could be hiding biosignatures just one centimeter beneath its surface.
For the last 20 years, Jupiter’s moon Europa has been regarded as our best bet of finding traces of alien life. Ever since NASA’s Galileo mission uncovered evidence that the icy moon may harbor a global ocean underneath its frozen surface, scientists have been pondering over its capacity of hosting life forms — or even just biosignatures to indicate whether or not it was once habitable.
Studying just a few samples from Europa’s subsurface ocean would help unlock many of the secrets that the tiny moon — the smallest of Jupiter’s four Galilean moons, measuring just 1,900 miles (3,100 kilometers) across — has been keeping for so long.
But getting a hold of such precious samples is no easy task, notes CNET. Europa is clad in an ice shell that’s 12.4 miles (20 kilometers) thick, which would require sending in some serious drilling equipment on a journey of 390 million miles (627 million kilometers) to the icy moon.
A more feasible option would be to ship off a lander that could study these samples once they’ve been expelled to the surface by the moon’s intense geological activity, such as the upwelling of the subsurface ocean or the geyser-like outgassing occurring on Europa, reports Space.com.
In fact, NASA is gearing up for an orbiter mission called the Europa Clipper — slated to launch in the early 2020s and to perform up to 45 close flybys of the moon in order to study its suspected water vapor plumes, the Inquisitr previously reported. The space agency is already envisioning a follow-up lander mission that would dig or drill into the moon’s surface in search for any biosignatures that could be lurking there.
— SPACE.com (@SPACEdotcom) July 23, 2018
Luckily, just like in Titan’s case, the largest moon that orbits Saturn, a new study has narrowed down the best places on Europa where to go looking or digging for potential traces of life.
While Titan may be harboring biological molecules inside its largest craters, as recently reported by the Inquisitr, Europa could be hiding amino acids right beneath its surface, shows a paper published yesterday in the journal Nature Astronomy.
In fact, these organic compounds — the simplest molecules that qualify as a potential biosignature and which represent the building blocks for proteins in living organisms — could be lying just one centimeter below the surface, the authors have discovered.
The main problem with studying potential amino acids on Europa’s surface is that these organic compounds would be cooked by radiation, NASA explains. The moon is constantly being pummeled by high amounts of radiation coming from Jupiter, which would destroy or at least chemically alter any amino acids climbing their way toward the surface from the ocean beneath Europa’s icy crust.
The good news is that the study has found a way to get around the issue. By mapping the radiation levels on Europa, the research pinpoints what regions are least affected and how deep under the moon’s surface it penetrates.
“If we want to understand what’s going on at the surface of Europa and how that links to the ocean underneath, we need to understand the radiation,” said Tom Nordheim, lead study author and a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “When we examine materials that have come up from the subsurface, what are we looking at? Does this tell us what is in the ocean, or is this what happened to the materials after they have been radiated?”
By using data from the Galileo and the Voyager 1 missions, his team built 3D models of Europa to see how Jupiter’s radiation bombards the moon, both on the surface and below the crust. The research uncovered that charged particles coming from Jupiter hit Europa’s equator the hardest and ease up toward the poles.
The findings suggest that around half the moon’s surface is occupied by harsh-radiation zones, shaped like ovals that connect to one another at their narrow ends.
In addition to spreading on the surface in oval-shaped regions, these high-intensity radiation zones only go four to eight inches (10 to 20 centimeters) deep into the crust.
“This is the first prediction of radiation levels at each point on Europa’s surface and is important information for future Europa missions,” said study co-author Chris Paranicas, a research scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.
The data reveals that a potential lander to touch down somewhere in the least affected area around Europa’s poles would only have to dig less than 0.4 inches (one centimeter) deep in middle- and high-latitude regions in order to find recognizable amino acids.
“Even in the harshest radiation zones on Europa, you really don’t have to do more than scratch beneath the surface to find material that isn’t heavily modified or damaged by radiation,” Nordheim told Space.com.
- [Source] : inquisitr