When it comes to searching for habitable locations in our solar system and beyond, one of the key requirements for life as we know it is the presence of liquid water. Whether that’s a liquid water ocean on the planet’s surface like we have here on Earth, or an ocean beneath a thick, icy crust, which is thought to be found on some of Jupiter’s icy moons, this is the first and most important indicator of potential habitability.
So it’s exciting to learn that two of Uranus’ moons may also host oceans. Though it is rarely studied because it is located so far from the sun, Uranus is known to host 27 moons, as well as rings, though all these moons are small at less than half the size of our moon. Researchers looked through almost 40-year-old data from the NASA Voyager 2 mission, which passed Uranus in 1985, to learn more about the energetic particles and magnetic fields around the planet.
They found evidence that two of the moons, Ariel and Miranda, are giving off plasma, and it isn’t clear why. One reason could be that either or both of the moons have oceans beneath icy crusts and are throwing out particles in plumes.
“It isn’t uncommon that energetic particle measurements are a forerunner to discovering an ocean world,” said lead author of the research, Ian Cohen of Johns Hopkins Applied Physics Laboratory, in a statement.
The researchers looked at data from Voyager 2’s Low-Energy Charged Particle (LECP) instrument, designed to measure various types of ions, electrons, and cosmic rays. They found a group of energetic particles grouped tightly around Uranus’ magnetic equator between the two moons, suggesting that the particles may have originated from the moons and been pushed toward the planet. They can’t tell which of the two moons the particles might have come from, but other moons in the solar system, like Saturn’s moon Enceladus, have shown plumes before. so that could explain the mechanism.
“We’ve been making this case for a few years now that energetic particle and electromagnetic field measurements are important not just for understanding the space environment, but also for contributing to the grander planetary science investigation,” Cohen said. “Turns out that can even be the case for data that are older than I am. It just goes to show how valuable it can be to go to a system and explore it firsthand.”
The research is accepted for publication in the journal Geophysical Research Letters.
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