Whether it is in movies, comic books, or regular conversation, nearly all of us have heard the word “alien” brought up in some context. Scientists have been studying the possibility of alien life for decades, and so far, they have come up with no evidence of life on other planets. Statistically, however, the existence of life elsewhere in the universe is practically guaranteed. In recent years, scientists have trained their eyes (and telescopes) on Europa, which is the sixth closest moon to the planet Jupiter, right in our solar system in search of this very evidence.
Famous astronomer Galileo Galilei discovered Europa in 1610, and for centuries, it has remained mysterious. As technology improved, we were able to gain more knowledge about Europa, and now, some believe that Europa may be able to inhabit life. Everything we know about Europa comes from pictures; no spacecrafts have landed on the moon as of now. We know that its crust is comprised of water-ice, and its core is iron-nickel. There is believed to be a subsurface ocean in between Europa’s core and crust, and this is where there is the highest chance for life to exist. The smoothness of Europa’s surface is an indication to scientists that underneath the ice, there could be a water ocean, maybe not so dissimilar to the oceans that we have on Earth, which as we know, are teeming with life.
All of us know about the tides on Earth that are created by the Moon, and there are similar forces between Jupiter and Europa. As Europa orbits Jupiter, it is sometimes closer to the planet and sometimes farther away. When Europa is closer to Jupiter, there is more gravitational attraction between these two bodies, which makes Europa stretch towards and away from Jupiter, giving it a more elliptical shape. When Europa is farther away, there is a lower gravitational force and the moon returns to a more spherical shape. These forces are thought to create tides in Europa’s ocean, and this tidal flexing movement could also be responsible for creating heat in Europa’s core. Since Europa can have temperatures as cold as -370 degrees Fahrenheit, having a source of heat is necessary for the existence of a liquid ocean. As you can see in pictures of Europa, there are a lot of crisscrossing cracks on the surface, and these cracks are likely the result of massive tides in the subsurface ocean exerting stress on the moon’s surface.
Scientists also believe that there may be active volcanoes under the surface of Europa that contribute to heating the water. Additionally, just as volcanoes are often sites of bacterial life on Earth, they could also be a habitat for life on Europa. There is still much more to learn about this mysterious moon, and we would need to make actual contact in order to determine whether there is life on Europa. As of now, no such missions are planned. However, the European Space Agency’s Jupiter Icy Moon Explorer is a mission that will conduct two flybys of Europa as it travels to Ganymede, which is the largest moon of Jupiter. This mission is set to launch in 2022, and hopefully it will provide us with more clues regarding the possibility of life on Europa.