Bright scars on a darker surface testify to a long history of impacts on Jupiter's moon Callisto in this image of Callisto from NASA's Galileo spacecraft.


Callisto is the most heavily cratered object in our solar system.

Callisto Overview

Callisto is Jupiter’s second largest moon and the third largest moon in our solar system. Its surface is the most heavily cratered of any object in our solar system. Images of Callisto captured by passing spacecraft show bright white spots standing out against darker regions. Scientists think the bright areas are mostly ice and the darker patches are areas where the ice has eroded.

Once thought to be a dead, inactive rocky body, data gathered by the Galileo spacecraft in the 1990s indicate Callisto may have a salty ocean beneath its icy surface. More recent research reveals that this ocean may be located deeper beneath the surface than previously thought, or may not exist at all. If an ocean is present, it’s possible the ocean is interacting with rock on Callisto, creating a potential habitat for life.

Pop Culture

Jupiter and its moons are popular subjects for science fiction writers and Callisto is no exception. It appears in several books and in the TV show “Cowboy Bebop,” Callisto has been terraformed and is home to mostly men.

In the 1930s, writer Harl Vincent had Earth and Callisto at war in his novel “Callisto at War.”

Isaac Asimov’s 1940 novel "The Callistan Menace” depicts Callisto as having an atmosphere of carbon dioxide and oxygen with lakes and vegetation. It’s also a deathtrap crawling with giant caterpillars.

Callisto gets a mention in Robert A. Heinlein's 1950 novel “Farmer in the Sky.” The book is mostly about Jupiter’s moon Ganymede, but it discusses an atmosphere being created so colonists can live on Callisto.

Philip K. Dick, author of “Blade Runner” and “The Minority Report” wrote a short story in 1955 called “The Mold of Yancy” about colonists living in a totalitarian society on Callisto.

Lin Carter created a series of eight books in the 1970s called the Callisto series. The books featured a soldier who is teleported to Callisto where he finds an ancient human civilization. In the book Callisto is like Earth, but some sort of illusion makes it seem uninhabitable to outsiders.

In Kim Stanely Robinson’s book “2312,” settlers have colonized Callisto’s giant moon-spanning impact crater Valhalla, starting from its innermost ring. The author envisions windows lining the inward-facing parts of the rings. As the colony grows and residents seek to maintain their space and independence, they settle in the different rings, creating separate colonies in each one.

The moon is also featured in several other books including:

  • The “Bio of a Space Tyrant” series by Piers Anthony
  • “Callisto: Dystopian Space” by Rob Lopez
  • “The Rowan” by Anne McCaffrey
  • “The Quiet War” by Paul J. McAuley
  • “Blue Mars” and “Galileo’s Dream” by Kim Stanley Robinson
  • “Wheelers” by Ian Stewart and Jack Cohen
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