Icy Water Moons That Might Host Life (Infographic)

There are a few icy worlds in the solar system that have the potential to host life.
There are a few icy worlds in the solar system that have the potential to host life. (Image credit: Space.com/Purch Creative Ops)

Icy Water Worlds That Might Host Life

Alien life may be lurking right in Earth's cosmic backyard. Some of the icy moons of Saturn and Jupiter are known to harbor subsurface oceans that could provide habitable environments.

In the dark, cold sections of the Earth's ocean floor, communities of life-forms survive on the heat and nutrients from hydrothermal vents. Under the ice of Antarctica, scientists have found rich microbial ecosystems.

These discoveries have opened up the possibility that life could also survive in extreme environments on other worlds.

There are five icy moons in our solar system that could potentially host extraterrestrial life.


This icy moon of Jupiter is thought to harbor a liquid-water ocean more than twice the volume of all Earth's oceans. The subsurface sea, which lies underneath a thick layer of subsurface ice, likely remains a liquid because of tidal heating, which (similar to tides on Earth) comes from the gravitational pull of Jupiter.

Other geologic activity in the moon's rocky core could create an additional heat source for life-forms. The ice layer on Europa is more likely at least 10 to 15 miles (15 to 25 km) thick, so getting a look at those life-forms would be extremely challenging. There may be, however, isolated lakes at shallower depths.

NASA has green-lit a mission to orbit Europa and learn more about this potentially habitable world.


Saturn's moon Titan might appear hospitable at first glance, because it is covered in rivers, lakes and oceans. Unfortunately, all of them are flowing with liquid ethane and methane, and all known life-forms need water to survive. In addition, the surface temperature on Titan is about minus 292 degrees Fahrenheit (minus 180 Celsikus) — far too cold for life as we know it.

But the active chemistry on Titan has led some scientists to hypothesize about how life could arise there. Living organisms create most of Earth's methane supply, but it's unclear where Tian's methane comes from. The source could be an underground ocean, where temperatures might be warmer.


The bluish-gray surface of Enceladus looks too frigid to host life, but under its surface lies a vast ocean. Just like on Europa, it's possible the underground ocean contains a suitable environment for life. Over 100 geysers on the moon's surface vent material from that ocean up and away from the satellite. Analysis of the plumes by the Cassini probe revealed water, ammonia, salts and organics (molecules that contain carbon, the building block for life on Earth).

A proposed mission to Enceladus would send a probe to collect samples from those plumes and analyze them in situ.


Like their siblings, Europa and Enceladus, the Jovian moons Ganymede and Callisto may have subsurface, liquid oceans. But in these cases, the underground seas would be buried under at least 60 miles (100 km) of rock.

These moons are less likely to support life than icy worlds like Enceladus, according to NASA. But the European Space Agency is planning a mission to study the buried oceans of the Jupiter system, with particular emphasis on Ganymede. 

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Calla Cofield
Senior Writer

Calla Cofield joined Space.com's crew in October 2014. She enjoys writing about black holes, exploding stars, ripples in space-time, science in comic books, and all the mysteries of the cosmos. Prior to joining Space.com Calla worked as a freelance writer, with her work appearing in APS News, Symmetry magazine, Scientific American, Nature News, Physics World, and others. From 2010 to 2014 she was a producer for The Physics Central Podcast. Previously, Calla worked at the American Museum of Natural History in New York City (hands down the best office building ever) and SLAC National Accelerator Laboratory in California. Calla studied physics at the University of Massachusetts, Amherst and is originally from Sandy, Utah. In 2018, Calla left Space.com to join NASA's Jet Propulsion Laboratory media team where she oversees astronomy, physics, exoplanets and the Cold Atom Lab mission. She has been underground at three of the largest particle accelerators in the world and would really like to know what the heck dark matter is. Contact Calla via: E-Mail – Twitter