Oceans enchant me. They have a magical quality: the soothing rhythm of waves crashing, the vulnerable feeling of smallness that comes from peering into the deep blue depths. Oceans seem to hold mysteries beyond our comprehension, and this extends far beyond Earth’s oceans to those of other worlds.

Did you know there are other oceans out there? We find them mostly on moons orbiting gas giants like Jupiter and Saturn. These Ocean Worlds hold vast, global oceans of liquid water underneath shells of ice; many of them seem to hold the three key ingredients for life as we know it: water, chemistry and energy. One of these Ocean Worlds, the gem of the Jovian system, is called Europa.

Europa orbits Jupiter every 3.5 days. Its liquid water ocean is massive, more than two times larger than all of Earth’s oceans combined.

By all rights it should be frozen solid, given that it is five times further from the sun than we are, but it isn’t. We think this is due to the fact that Europa’s orbit around Jupiter isn’t a perfect circle. That means each time it orbits the largest planet in the solar system, this moon experiences a bit more gravity when it’s closer, and a bit less of a pull when it’s further away.

That different pulling leads to flexing, friction and heat. Enough heat to keep the ocean liquid, and possibly even drive geothermal activity such as hydrothermal vents at this alien ocean’s sea floor.

Europa appears to meet all criteria for life as we know it underneath it’s icy crust. The ocean has liquid water, undoubtedly containing a multitude of organic molecules (similar to those we see in comets and asteroids that formed at the same time as our solar system coalesced), and enough energy to keep the ocean from freezing.

Water, chemistry and energy. This gives us an opportunity to test an important theory about life. Are we special? Is life on Earth incredibly unique, making us terribly alone in this vast, empty universe? Or is biology just the natural evolution of a planetary system?

If you have the three key ingredients (water, chemistry and energy) and you mix them together and wait long enough, will life form? We won’t know unless we explore other worlds with those same conditions and test the theory.

On Oct.14, 2024, NASA’s Europa Clipper Mission launched from Kennedy Space Center in Florida, embarking on a nearly six-year journey (space is big) to reach Jupiter’s moon Europa, one of the most compelling destinations in our cosmic backyard to explore the potential for life outside of Earth.

The spacecraft’s payload includes 10 investigations capable of high-resolution imaging and stereo mapping, smelling and tasting the vapors and grains sputtered off the surface, and peering through the ice shell to constrain properties of the subsurface ocean like composition and salinity.

What we learn with Europa Clipper may revolutionize our understanding of the conditions needed for life to form in an alien ocean. By peeling back the layers of mystery shrouding Europa’s ocean, we could learn more about our own oceans and the potential for life beyond our own cosmic backyard. I cannot wait to see what we will discover!

Oceans are truly enchanting. And I hope the next time you visit one of ours on Earth, you might reflect on how oceans are something we share with many other worlds, not only in our own solar system but possibly innumerable others around far-away stars in other galaxies across our universe.

Perhaps we share something else in common with these other worlds, too: life.

Morgan L. Cable, who has a Ph.D. in inorganic chemistry from Caltech, has multiple team leadership roles on the Europa Clipper probe recently launched by NASA’s JPL, and helped create its spectrometer, which will map Europa’s surface and search for organics, salts and minerals. Speaking of enchanted oceans, she is also a surfer.