Jupiter has upwards of 67 moons, and one of the largest of those natural satellites has been the subject of great interest and study because of the ocean that scientists believe exists under the moon’s icy crust.
A recent NASA study discovered that the chemical balance of the deep, salty ocean on Europa could be roughly the same as it is on Earth, making it ripe for the existence of life forms.
“We’re studying an alien ocean using methods developed to understand the movement of energy and nutrients in Earth’s own systems,” said Steve Vance, lead researcher at NASA’s Jet Propulsion Laboratory. “The cycling of oxygen and hydrogen in Europa’s ocean will be a major driver for Europa’s ocean chemistry and any life there, just as it is on Earth.”
The scientists created a model showing the hydrogen and oxygen levels on the Jupiter moon without any volcanic activity. According to their data, Europa probably produces 10 times more oxygen than hydrogen, which is the same ratio as Earth. Hydrogen is produced by ocean water reacting with the moon’s rocky crust.
The study worked with the idea that Europa’s crust has slowly been cooling, creating more hydrogen, while the radiation from Jupiter breaks water molecules into hydrogen and oxygen. When that oxygen reacts with compounds present in the ocean water, including the hydrogen, it is recycled on the moon’s interior.
“The oxidants from the ice are like the positive terminal of a battery, and the chemicals from the seafloor, called reductants, are like the negative terminal. Whether or not life and biological processes complete the circuit is part of what motivates our exploration of Europa,” Kevin Hand, a planetary scientist at JPL who co-authored the study with Vance, said.
According to Vance, researchers previously speculated that volcanism is paramount for creating a habitable environment in Europa’s ocean. If such activity is not occurring in its rocky interior, the thinking goes, the large flux of oxidants from the surface would make the ocean too acidic, and toxic, for life. “But actually, if the rock is cold, it’s easier to fracture. This allows for a huge amount of hydrogen to be produced by serpentinization that would balance the oxidants in a ratio comparable to that in Earth’s oceans,” he said.
Although these discoveries are based on theoretical models of the moon, NASA plans to send a probe to visit Europa in about a decade for direct observation to find out if there are any signs of life on Jupiter’s distant moon.
Image Credits: 1) NASA/JPL-Caltech, 2) NASA/JPL-Caltech/ SETI Institute