Study: Tides on Enceladus keep ocean warm enough for life

Based on a computer model, astronomers have concluded that the hydrothermal activity in Saturn’s moon Enceladus, caused by the tidal action of Saturn’s gravity, creates enough heat to keep the ocean below the ice surface liquid.

The scientists have created a computer model based on data collected by the Cassini spacecraft during its mission. This model simulated the heat generated by Saturn’s gravity on the small ice moon. According to the simulation, the friction caused by the tidal action in the rock in the moon’s core would generate more than 10 billion to 30 billion watts of heat.

Scientists have always wondered how the ocean beneath the ice surface of Enceladus could be liquid in such a small cold moon; Saturn’s gravitational pull was thought to be insufficient to generate sufficient heat. However, the results of this research show that the heat generated in the small ice moon is sufficient to warm the ocean below the ice surface for many tens of millions of years to even billions of years. This is long enough to achieve favorable conditions for life: there is water, there is a continuous source of energy and there are organic molecules. According to the researchers, the heated water creates heat in particular at the South Pole, where the geysers, which blow water vapor into space, are located at breaks and cracks in the ice on the moon’s surface.

Based on measurements from Cassini, which flew through a gas plume from Enceladus in October 2015, NASA concluded that there is hydrogen in the geyser fountains. Previously, it was suspected that there is a large water reservoir under the ice surface. In 2015, after studying image information from Cassini for seven years, NASA confirmed that there is actually an ocean on Enceladus that spans its entire surface. The process in Enceladus, which creates hydrogen molecules, is similar to the chemical processes at thermal wells located at the bottom of Earth’s oceans. Cassini spacecraft sank in Saturn’s atmosphere in September, but the data collected and sent to Earth during its 20-year mission will be used for scientific research for many years to come.

The scientists have published their research in the scientific journal Nature Astronomy, under the title Powering prolonged hydrothermal activity inside Enceladus.