Question 1

True or false: Callisto was discovered by Galileo Galilei in 1610 along with three other Jovian moons.

Accepted Answer

True. Galileo spotted Callisto, Io, Europa, and Ganymede in January 1610, revolutionizing astronomy.

Question 2

True or false: Callisto is the largest moon in the solar system, even bigger than Mercury.

Accepted Answer

False. Ganymede is the largest moon; Callisto is only slightly smaller than Mercury but less dense.

Question 3

True or false: Callisto is tidally locked to Jupiter, always showing the same face.

Accepted Answer

True. Like our Moon, Callisto's rotation matches its orbit, so one hemisphere permanently faces Jupiter.

Question 4

True or false: Callisto has the oldest, most heavily cratered surface in the solar system.

Accepted Answer

True. Its ancient, icy crust is saturated with impact craters, making it the most heavily cratered known object in the solar system.

Question 5

True or false: Callisto likely has a subsurface ocean of liquid water beneath its icy crust.

Accepted Answer

True. Magnetic field data from Galileo spacecraft strongly suggests a salty ocean exists 100-150 km below the surface.

Question 6

True or false: Callisto has a thin carbon dioxide atmosphere that freezes out during its night.

Accepted Answer

False. Callisto’s exosphere contains CO2, but it doesn't actually freeze at night—its tenuous atmosphere is always present.

Question 7

True or false: Callisto experiences volcanic eruptions from cryovolcanoes that spew liquid nitrogen.

Accepted Answer

True. Cryovolcanism on Callisto is theorized, but only Enceladus and Triton have confirmed geysers—Callisto's are unconfirmed.

Question 8

True or false: Callisto generates its own magnetic field strong enough to deflect Jupiter's radiation.

Accepted Answer

False. Callisto lacks an internal dynamo; its induced magnetic field is a response to Jupiter's magnetosphere, not self-generated.

Callisto Trivia Questions