Huygens visits a truly alien world

On January 14, 2005, the Huygens probe, part of the Cassini-Huygens mission—a collaboration between NASA, the European Space Agency, and the Italian Space Agency—made history with humanity’s first landing on an outer solar system moon: Titan, Saturn’s enigmatic satellite. These images made quite an impression on me at the time, as they showed something far more alien than anything I had previously seen from Moon, Mars, or elsewhere. What’s more, this mission revolutionized our understanding of Titan, revealing a world strikingly similar to early Earth with its weather systems and surface liquids (mostly methane), thereby altering our perceptions of where life-sustaining environments might exist in the solar system.