The Solar System - Word Search - PUZZLE #16 RHEA - August 2025

PUZZLE #16 - RHEA 

IN-CONTEXT WORD DEFINITIONS

Saturnian: Saturnian refers to anything related to Saturn. With regard to Rhea, it means that Rhea is a Saturnian moon — one of many natural satellites orbiting the planet Saturn. Its characteristics, such as its orbit, composition, and surface features, are influenced by its relationship with Saturn.

Giovanni: Giovanni refers to Giovanni Domenico Cassini, the 17th-century Italian-French astronomer who discovered Rhea in 1672.

Oxygen: Molecular oxygen (O₂) has been detected in Rhea’s exosphere. It is thought to be produced when charged particles from Saturn’s magnetosphere strike Rhea’s icy surface, breaking apart water molecules and releasing oxygen atoms, which recombine into O₂.

Cassini: The Cassini spacecraft (1997–2017) conducted multiple flybys of Rhea and provided the most detailed data we have about the moon. Cassini discovered Rhea’s thin exosphere, mapped its surface, and observed features like Tirawa crater, fractures, and possible ring material.

Rock-Ice Mixture: Rhea is composed of a rock-ice mixture, with its interior made up of about 75% water ice and 25% rock by mass. This composition makes it similar to other icy moons in the outer solar system and contributes to its low density and heavily cratered surface.

Fractures: Fractures on Rhea’s surface are long, linear features—cracks in the icy crust—possibly caused by tectonic activity, thermal stress, or impacts. Some fractures resemble faults or grabens, hinting at a complex geological history despite Rhea’s overall geologic inactivity.

Tirawa: Tirawa is a large impact crater on Rhea, roughly 360 kilometers wide. It’s one of the moon’s most prominent surface features, with a central peak and rugged terrain. Its size and preservation provide clues about Rhea’s surface age and impact history.

Mamaldi: Mamaldi is another named crater on Rhea. Though smaller than Tirawa, it contributes to the heavily cratered appearance of the moon, which indicates a surface that has remained relatively unchanged for billions of years.

Bombardment: Bombardment refers to the heavy impacts by meteoroids and comets that Rhea has experienced over time. This process has left the moon’s surface covered in craters, from small pits to large basins like Tirawa, recording a long history of collision events in the outer solar system.

Secret Word: Named for the Titaness of Greek mythology, who was the wife of Cronus (the Greek counterpart of the Roman god Saturn) and the mother of the first generation of Olympian gods.