Author: Ariana Bojan
Co-Author: K.A.Kenny
Published by Hub For Science
Published: March 16, 2026
Category: [Science Rabbit Hole]
Some of Jupiter’s moons, especially Europa, may have oceans beneath their ice that could support life. Spacecraft and telescopes have detected evidence of these oceans, and upcoming missions like Europa Clipper will study them further to see if they are habitable.
For a long time scientists believed that life beyond Earth would most likely exist on planets similar to our own. Over the past few decades this idea has changed. Research has shown that several moons in our solar system may contain the conditions needed for life. Some of the most promising candidates orbit Jupiter. Moons such as Europa, Ganymede, and Callisto may contain large oceans beneath their icy surfaces.
Scientists now believe that these hidden oceans could provide environments where life might survive. These discoveries come from decades of spacecraft exploration, telescope observations, and careful scientific analysis. Understanding these moons may help answer one of the most important questions in science: whether life exists anywhere else in the universe.
Liquid water is considered one of the most important ingredients for life. On Earth every known organism depends on water to survive. For this reason scientists search for places where liquid water might exist.
One of the strongest examples is Europa. This moon is covered with a thick layer of ice, but scientists believe that beneath the ice lies a global ocean of salty liquid water. According to research published by NASA, the amount of water inside Europa may be greater than the total amount of water in all of Earth’s oceans combined.
Europa is thought to have several layers inside its structure. At the center there is likely a metallic core surrounded by a rocky mantle. Above this layer scientists believe there is a deep ocean of liquid water. On the surface sits a thick shell of frozen ice. Estimates suggest that the ice crust may be between fifteen and twenty five kilometers thick, while the ocean below may reach depths of more than one hundred kilometers.
Scientists are interested in this ocean because it could remain liquid for billions of years. If heat and chemicals are present, simple life forms such as microbes might survive in such an environment.
Even though humans have never landed on Europa or drilled through its ice, scientists have several methods that allow them to understand its internal structure.
One important clue comes from the surface of the moon. Images show that Europa is covered with long cracks and ridges that stretch across the entire moon. There are very few large impact craters compared with other moons. This suggests that the surface is relatively young and is constantly changing.
Scientists think the icy surface may slowly move and shift because liquid water exists beneath it. Some regions of Europa contain what researchers call chaos terrain. In these areas large blocks of ice appear to have broken apart and moved around, which could happen if the ice floats on top of an ocean.
Another important piece of evidence comes from magnetic field measurements. Jupiter has an extremely powerful magnetic field. When spacecraft measured the magnetic environment around Europa they discovered that the moon creates its own changing magnetic signal. Scientists concluded that this effect could be produced by a layer of salty liquid water inside the moon because salt water conducts electricity.
Gravity measurements also help scientists estimate how mass is distributed inside a moon. By carefully tracking the movement of spacecraft as they fly past, researchers can determine how dense the interior layers might be.
Knowledge about Jupiter’s moons comes from several space missions over the past fifty years.
The first close exploration began with the spacecraft Pioneer 10 and Pioneer 11 in the early nineteen seventies. These missions flew past Jupiter and collected the first detailed measurements of the planet and its environment. Although their cameras were limited, they confirmed that Jupiter’s system was extremely complex.
A few years later the spacecraft Voyager 1 and Voyager 2 provided far better images. When Voyager photographed Europa in nineteen seventy nine scientists noticed that the moon had a bright icy surface covered in cracks. The lack of craters suggested that the surface was active and possibly renewed by processes occurring beneath the ice.
The mission that provided the strongest evidence for an ocean was the spacecraft Galileo. This probe orbited Jupiter from nineteen ninety five until two thousand three. During this time it performed multiple close flybys of Europa and other moons.
Galileo carried instruments that measured magnetic fields, gravity, and surface composition. The data it collected strongly supported the theory that Europa contains a global salty ocean beneath its ice shell. Many scientists consider Galileo’s discoveries to be one of the most important milestones in the study of ocean worlds.
More recently the spacecraft Juno has been studying Jupiter since two thousand sixteen. While its main goal is to investigate the planet itself, it has also provided additional observations of Europa and other moons.
The telescope Hubble Space Telescope has also contributed to these discoveries. Observations from Hubble suggest that plumes of water vapor may sometimes erupt from Europa’s surface. If these plumes come from the ocean below, they could allow future spacecraft to study ocean material without drilling through the ice.
Scientists are preparing new missions that will explore these moons in much greater detail.
One of the most important upcoming missions is the spacecraft Europa Clipper. This mission is designed specifically to study Europa and determine whether the moon could support life. Europa Clipper will perform dozens of close flybys while measuring the thickness of the ice shell, mapping the surface, and studying the chemistry of the moon.
Another major mission is Jupiter Icy Moons Explorer, often called JUICE. This spacecraft launched by the European Space Agency will study Europa, Ganymede, and Callisto. It carries instruments that can analyze ice layers, measure magnetic fields, and investigate possible subsurface oceans.
These missions will help scientists better understand whether the environments inside these moons contain the chemical ingredients and energy sources needed for life.
Research on Jupiter’s moons is important for several reasons. First it may help scientists understand how life begins. If life were discovered in Europa’s ocean it would suggest that life can develop in many different environments, not just on planets similar to Earth.
Second the technologies developed for these missions help improve spacecraft design. Instruments such as ice penetrating radar, radiation resistant electronics, and autonomous navigation systems will be important for future deep space exploration.
Finally these discoveries help astronomers search for habitable environments around other stars. Many scientists now believe that ocean worlds may be common throughout the universe. By studying Europa and other moons in our own solar system researchers can better understand how to detect similar worlds orbiting distant stars.
