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A complete new mapping of the radiation that tears the frozen moon of Jupiter Europa reveals where scientists must look – and how deep they must go – when they are looking for signs of habitability and biosignatures.
Since NASA 's Galileo mission demonstrated the existence of a global ocean beneath the icy shell of Europe in the 1990s, scientists have considered this moon as the only one in the world. one of the most promising places in our solar system. There is even evidence that salt water that slides around the moon's interior is making its way to the surface.
By studying this material from the inside, scientists developing future missions hope to learn about the livability of the ocean. is bombarded by a constant and intense explosion of Jupiter radiation. This radiation can destroy or alter the materials transported to the surface, making it more difficult for scientists to know if this really represents the conditions in the ocean of Europe.
While scientists plan Europa's exploration, they are struggling with many unknowns. Is radiation the most intense? How deep are the energy particles? How does radiation affect what is on the surface and below, including potential chemical signs, or biosignatures, that could imply the presence of life
A new scientific study published today in Nature Astronomy complete the modeling and mapping of radiation at Europa and proposes key pieces for the puzzle. The lead author is Tom Nordheim, a researcher at NASA's Jet Propulsion Laboratory in Pasadena, California.
"If we want to understand what is happening on the surface of Europa and how it relates to the ocean, we must understand radiation," said Nordheim. "When we look at materials that come out of the basement, what do we see, does that tell us what's in the ocean, or is that what happened to the materials?" after they've been radiated? "
The overflights of Galileo from Europa twenty years ago and the electronic measurements of NASA's Voyager 1 spacecraft, Nordheim and his team looked closely at the electrons that were blowing up the surface of the moon. They found that radiation doses vary by location. The harsher radiations are concentrated in the areas around the equator, and the radiation is getting closer to the poles.
Areas of hard radiation are in the form of oval regions, connected at the narrow ends, covering more than half of the "C" and is the first prediction of radiation levels at each point of the surface of the surface. Europe and it's important information for future Europa missions, "said Chris Paranicas, co-author of the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.
Scientists now know where to find the least radiation-impaired regions, which could be a crucial piece of information for the Europa Clipper led by the JPL, NASA's mission to orbit Jupiter and follow Europa with nearly 45 flybys nearby. The spacecraft could be launched as early as 2022 and will carry cameras, spectrometers, plasma and radar instruments to study the composition of the moon's surface, its ocean and materials ejected from the surface.
did not stop with a two-dimensional map. He went further, measuring how far the radiation penetrates the surface and building 3D models of the most intense radiation on Europa. The results tell us how deep scientists have to dig or drill, during a possible future Europa landing mission, to find biosignatures that could be retained.
The answer varies from 10 to 20 centimeters In regions of Europe located at middle and high latitudes, towards the moon's poles, the regions most exposed to radiation go down to less than 0, 4 inches (1 centimeter). To reach this conclusion, Nordheim tested the effect of radiation on amino acids. , basic elements for proteins, to understand how Europa's radiation would affect potential biosignatures. Amino acids are among the simplest molecules that are considered a potential biosignature, notes the newspaper.
"The radiation that bombards the surface of Europe leaves a fingerprint," said Kevin Hand, co-author of the new research project Mission de Lander. "If we know what this fingerprint looks like, we can better understand the nature of all organic and possible biosignatures that could be detected in future missions, whether spacecraft flying over or landing on Europa
" Is good news for potentially fresh ocean materials that have not been heavily modified by the radiation footprint, "Hand said.
Learn more:
The rising ocean of Europe
More information:
T. A. Nordheim et al. Preservation of potential biosignatures in the shallow subsurface of Europa, Nature Astronomy (2018). DOI: 10.1038 / s41550-018-0499-8
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