In a familiar galaxy far away, a small, swirling pale blue dot spent billions of years concocting the perfect recipe for life. At the heart of this remarkable process was an unassuming chemical element called phosphorus, which played a crucial role in the formation of DNA and RNA—the building blocks of life. Some scientists even argue that our life should be referred to as “phosphorus-based” rather than “carbon-based” due to its importance.
Recently, utilizing data from NASA’s Cassini mission, scientists have made an intriguing discovery. They found evidence of phosphorus, the essential ingredient for life, in the icy moon of our very own solar system—Enceladus, a moon of Saturn. Enceladus possesses a vast global ocean beneath its icy surface and regularly shoots water geysers into space, capable of filling an Olympic-sized swimming pool within hours. The grains of ice collected by Cassini from these plumes exhibited clear traces of phosphorus, specifically in the form of phosphates that can be readily absorbed and utilized by living organisms.
Previous investigations have identified other building blocks of life within Enceladus’ extensive oceans, such as carbon, hydrogen, nitrogen, sulfur, and oxygen. However, the discovery of phosphorus is particularly significant due to its essential role. Phosphorus is a crucial component of the plasma membrane that safeguards our cells—the fundamental units of life.
To add to the excitement, scientists estimate that phosphorus concentrations on Enceladus are at least 100 times higher than those in Earth’s oceans. This discovery implies that “the ocean of Enceladus is now known to satisfy what is generally considered to be the strictest requirement for life,” as Dr. Christopher Glein, a co-author of the study, explained.
Computer models and geochemical experiments further suggest that the high concentrations of phosphate observed in Enceladus’s oceans, as well as in other icy ocean worlds beyond Jupiter, are a result of phosphate’s solubility in these environments.
While we know that habitable ocean worlds like Earth must orbit within specific distances from their host stars to maintain liquid water on their surfaces, the revelation of an ocean world hidden beneath an icy exterior expands the realm of possibilities for the existence of habitable entities throughout the Milky Way galaxy.