The Solar System - Word Search - PUZZLE #6 MARS - August 2025

PUZZLE #6 - MARS 

IN-CONTEXT WORD DEFINITIONS

Permafrost: On Mars, permafrost refers to the ground (soil, rock, or sediment) that remains at temperatures permanently below the freezing point of water for extended periods. Given the planet's mean surface temperature of -80°C, Mars is globally covered by permafrost. This permafrost can be ice-free ("dry permafrost") or ice-rich ("ice-rich permafrost" or "ground ice"), depending on local climate and geological conditions. Ground ice is stable at middle and high latitudes, occurring as a distinct ice table beneath a layer of dry permafrost.

Red: Mars is known as the Red Planet because of its iron oxide (rust)-rich soil and dust, which gives it a reddish appearance when viewed from space or Earth.

Hesperian: This refers to a major geological period in Mars's history, spanning roughly from 3.7 to 2.9 billion years ago. It is named after the Hesperia Planum region on Mars. The Hesperian period saw a decrease in the rate of large impact events compared to the preceding Noachian period. It was characterized by extensive volcanism, creating vast plains of flood basalts and the formation of large shield volcanoes like Olympus Mons. This period also saw catastrophic releases of water carving out huge outflow channels, suggesting significant, albeit possibly episodic, water activity, even as the planet's climate became colder and drier. Sulfuric acid weathering became more prominent than the earlier clay formation during this period.

Volcano: A volcano is a vent or opening in a planet’s surface through which molten rock (magma), ash, and gases escape from an astronomical object. Mars has the largest volcano in the solar system, Olympus Mons, and many other extinct shield volcanoes. These features suggest Mars once had significant volcanic activity.

Plains: Mars has vast plains, such as Amazonis Planitia and Utopia Planitia, which are flat, expansive regions formed by ancient lava flows or sediment deposits.

Noachian: This is the oldest of the three generally recognized geological periods on Mars, lasting from approximately 4.1 to 3.7 billion years ago. It is named after Noachis Terra, a heavily cratered highland region on Mars. The Noachian period was marked by heavy bombardment by asteroids and comets, forming large impact basins like Hellas and Argyre. Extensive erosion, likely driven by a thicker atmosphere and potentially warmer, wetter conditions (at least episodically), formed numerous valley networks. Volcanic activity was also significant during this period, particularly in the Tharsis region. Evidence suggests the presence of liquid water, possibly even oceans or large lakes, during the Noachian. Chemical alteration of rocks during this period produced clay minerals, known as phyllosilicates. Towards the end of the Noachian, as Mars lost its global magnetic field, the climate likely transitioned to a colder, more arid state.

Probe: A probe is a robotic spacecraft sent to explore Mars, either by orbiting, landing, or roving. Examples include NASA’s Perseverance rover, Curiosity, and the InSight lander.

Clouds: Mars has thin clouds made of water ice or carbon dioxide, especially near the poles and in the morning sky. These clouds are not dense like Earth's but are still visible from orbit.

Marsquakes: These are seismic events, or quakes, that occur on Mars, similar to earthquakes on Earth. Unlike Earth, Mars lacks plate tectonics, which is the primary cause of earthquakes. Instead, marsquakes are thought to be caused by the planet's cooling and shrinking, leading to the formation of faults or cracks in the crust. The largest marsquake ever detected happened in May 2022 and had a magnitude of 4.7. Marsquakes are detected by seismometers, like the one on NASA's InSight lander, which help scientists study the planet's interior structure by analyzing the seismic waves generated by these quakes. Analyzing the velocity of different seismic waves inside Mars has revealed surprising observations about the Martian core, indicating it's larger than previously thought.

Secret Word: Refers to anything related to Mars, including its surface features, atmosphere, or hypothetical life forms. It can also be used to describe fictional inhabitants of the planet in science fiction.