Jupiter’s moons are much hotter than they should be given their distance from the Sun. During tidal heating, the gravitational pulls of Jupiter’s moons and the planet itself stretch and squeeze the satellites enough to warm them. As a result, some of Jupiter’s icy moons are warm enough inside to house oceans of liquid water. In the case of the rocky moon Io, tidal heating turns the rock into magma. Scientists previously thought that the gas giant Jupiter was responsible for much of the tidal heating associated with the liquid interior of the moons. However, a new study published in Geophysical Research Letters has shown that the interaction of its moons is more responsible for its heating than Jupiter alone.
“This is surprising because the moons are much smaller than Jupiter. It’s unexpected that they can create such a large tidal response, ”explains lead author Hamish Hay, a researcher at the Jet Propulsion Laboratory in Pasadena, California, who did the research when he was a graduate student at the University of Arizona lab.
Understanding how the moons affect each other is important. Ultimately, this may shed light on the evolution of the lunar system as a whole. Jupiter has about 80 moons, the four largest of which are Io, Europa, Ganymede, and Callisto.
“Protecting underground oceans from freezing over time requires a delicate balance between internal heating and heat loss. And yet we have some evidence that Europa, Ganymede, Callisto and other moons must be ocean worlds, ”said co-author Anthony Trinh, a postdoctoral fellow at the University of Arizona lab. “Io, the moon closest to Jupiter, exhibits widespread volcanic activity, another consequence of tidal heating. But with a higher intensity, like the Earth in its early history. Ultimately we want to understand the source of all this heat and its influence on the evolution and habitability of many worlds in the solar system and beyond. ”
According to the researchers’ model, the influence of Jupiter alone cannot create tides of heating with the desired frequency, because the oceans of the moons are too massive. It wasn’t until the researchers added the gravitational influence of other satellites that they began to notice tidal forces approaching the natural frequencies of the moons.
When the tides created by other objects in Jupiter’s lunar system match the natural resonance frequency of each moon, it begins to heat up more than the tides raised by Jupiter alone, and in the most extreme cases, this can lead to ice melting or fractures inside.
Scientists hope that future research will be able to determine the true depth of the oceans within these moons.