NASA is gearing up for the Europa Clipper mission that will study the Jovian moon Europa. Europa is one of the more interesting objects in the solar system as it’s believed to have a subsurface ocean under its frozen exterior that could potentially harbor life. Scientists funded by NASA are studying the cumulative effects of small impacts on the surface of Europa.
New research and modeling estimates how far down the surface is disturbed by a process called “impact gardening.” researchers estimate the surface of Europa has been churned by small impacts to an average depth of about 12 inches over tens of millions of years. Thus, any molecules that might qualify as potential biosignatures, including chemical signs of life, could be affected at that depth.
Impacts with the surface of Europa would churn some material to the surface where radiation would likely break the bonds of any potentially large and delicate molecules generated by biology. Some of the material on the surface would also be pushed downward where it would mix with the subsurface. Study lead author Emily Costello says that scientists will have to look below the zone where impacts have been gardening if we want to find pristine chemical biosignatures.
She notes that any chemical biosignatures in areas shallower than 12 inches may have been exposed to destructive radiation. Scientists have long known that impact gardening is likely taking place on Europa and other airless bodies around the solar system. However, the new models provide the most comprehensive picture yet of the process.
The study also makes the case that Europa’s mid to high-latitude areas would be less affected by impact gardening and radiation. NASA plans to launch the Europa Clipper mission in 2024. It will conduct a series of close flybys of Europa as it orbits Jupiter.