The Solar System - Word Search - PUZZLE #7 PHOBOS - August 2025

PUZZLE #7 - PHOBOS 

IN-CONTEXT WORD DEFINITIONS

Martian Moon: Phobos is a Martian moon, meaning it orbits the planet Mars. It is the larger and closer of Mars's two natural satellites, the other being Deimos.

PHOBOS: PHOBOS (always capitalized when referring to the moon) is the innermost moon of Mars, irregular in shape, heavily cratered, and extremely small — only about 22 km (14 miles) across at its widest point.

Stickney: Stickney is the largest crater on Phobos, spanning about 9 km (5.6 miles). It dominates one end of the moon and likely resulted from a major impact event.

Regolith: Phobos is covered in a layer of regolith, which is a loose, dusty surface material made from billions of years of micrometeorite impacts. It gives the moon a soft, powdery texture.

Asteroid: Phobos resembles a captured asteroid due to its irregular shape, small size, and composition. Some scientists believe it may once have been an asteroid from the outer asteroid belt, though its exact origin is still debated.

Roche Radius: Phobos is slowly spiraling inward toward Mars. When it reaches the Roche radius (the distance within which a celestial body will disintegrate due to tidal forces), it will likely break apart and possibly form a ring around Mars.

Fast Orbit: Phobos has an extremely fast orbit, completing a full revolution around Mars in just 7.66 hours — faster than Mars rotates. As a result, it rises in the west and sets in the east.

Porosity: Phobos has high porosity, meaning it contains a lot of empty space inside. This suggests it might be a rubble pile — a loosely held-together collection of rocks and dust rather than a solid body.

Doomed: Phobos is often described as "doomed" because it is slowly getting closer to Mars — at a rate of about 2 cm per year — and is expected to either crash into Mars or break apart in about 30–50 million years.

Secret Word: The name comes from the Greek god of fear, who was the son of Ares (Mars in Roman mythology). It symbolizes "fear", consistent with its brother Deimos, which means "terror" or "dread."