A recent study led by researchers from the University of Oxford, Southwest Research Institute, and the Planetary Science Institute in Tucson, Arizona has found significant heat flow at Enceladus’ north pole. This challenges earlier beliefs that heat loss was only present at the moon’s active south pole. The discovery suggests that Enceladus emits more heat than previously thought, which may increase its potential to support life.
Enceladus is known for its global salty subsurface ocean beneath an icy shell. Scientists believe this ocean could be one of the most promising places in the solar system to find life beyond Earth due to the presence of liquid water, heat, and essential chemicals such as phosphorus and complex hydrocarbons.
The research team used data from NASA’s Cassini spacecraft to analyze temperature changes at Enceladus’ north pole during deep winter in 2005 and summer in 2015. By comparing expected surface temperatures with infrared observations from Cassini’s Composite InfraRed Spectrometer (CIRS), they discovered that the north pole’s surface was about 7 Kelvin warmer than predicted. According to lead author Dr Georgina Miles of Southwest Research Institute and visiting scientist at Oxford's Department of Physics, “Eking out the subtle surface temperature variations caused by Enceladus’ conductive heat flow from its daily and seasonal temperature changes was a challenge, and was only made possible by Cassini’s extended missions.” She added, “Our study highlights the need for long-term missions to ocean worlds that may harbour life, and the fact the data might not reveal all its secrets until decades after it has been obtained.”
The measured heat flow at the north pole is approximately 46 ± 4 milliwatts per square metre—about two-thirds of what is observed through Earth’s continental crusts. Across all of Enceladus, this translates into a total conductive heat loss of around 35 gigawatts. When combined with previous estimates from the south pole, total heat loss rises to 54 gigawatts—a figure closely matching predictions for tidal heating input caused by Saturn’s gravity.
This balance between energy production and loss suggests that Enceladus’ subsurface ocean can remain liquid over geological timescales. Corresponding author Dr Carly Howett from Oxford’s Department of Physics and Planetary Science Institute said: “Understanding how much heat Enceladus is losing on a global level is crucial to knowing whether it can support life. It is really exciting that this new result supports Enceladus’ long-term sustainability, a crucial component for life to develop.”
The study also showed that thermal data can help estimate ice shell thickness—an important factor for future missions aiming to explore Enceladus’ ocean using robotic landers or submersibles. The findings suggest ice depths range from 20–23 km at the north pole with a global average between 25–28 km.
Researchers note that while these results are promising for long-term habitability, further work is needed to determine if Enceladus’ ocean has existed long enough for life to develop. The age of this subsurface sea remains uncertain.
The study “Endogenic heat at Enceladus’ north pole” appears in Science Advances.