Essential Ingredient for Life Found in Abundance on Europa

A new study published online in the Astrophysical Journal Letters (arXiv.org version) shows that hydrogen peroxide – an important energy supply for life – is abundant across much of the surface of Jupiter’s icy moon Europa.

Europa global views in natural and enhanced colors (NASA / JPL / University of Arizona)

Europa global views in natural and enhanced colors (NASA / JPL / University of Arizona)

“Life as we know it needs liquid water, elements like carbon, nitrogen, phosphorus and sulfur, and it needs some form of chemical or light energy to get the business of life done,” said first author Dr Kevin Hand of NASA’s Jet Propulsion Laboratory, Pasadena.

“Europa has the liquid water and elements, and we think that compounds like peroxide might be an important part of the energy requirement. The availability of oxidants like peroxide on Earth was a critical part of the rise of complex, multicellular life,” he said.

Dr Hand and his colleague Dr Mike Brown from California Institute of Technology in Pasadena think hydrogen peroxide is an important factor for the habitability of the global liquid water ocean under Europa’s icy crust because hydrogen peroxide decays to oxygen when mixed into liquid water.

“At Europa, abundant compounds like peroxide could help to satisfy the chemical energy requirement needed for life within the ocean, if the peroxide is mixed into the ocean,” Dr Hand explained.

The team analyzed data collected from two instruments on the Keck II telescope on Mauna Kea, Hawaii, over four nights in 2011. The highest concentration of peroxide found was on the side of Europa that always leads in its orbit around Jupiter, with a peroxide abundance of 0.12 percent relative to water.

“What we still don’t know is how the surface and the ocean mix, which would provide a mechanism for any life to use the peroxide,” Dr Brown added.

______

Bibliographic information: Hand KP, Brown ME. 2013. Keck II Observations of Hemispherical Differences in H2O2 on Europa. ApJ 766 L21; doi: 10.1088/2041-8205/766/2/L21