Titan is Saturn's largest moon, unique for its thick, hazy atmosphere and surface lakes, rivers, and seas of liquid methane and ethane, making it the only place besides Earth with stable surface liquids. This icy world, far colder than Earth (around -290°F / -179°C), features water ice bedrock, hydrocarbon dunes, and a potential subsurface ocean, with ongoing research by missions like NASA's Dragonfly exploring its potential for simple, prebiotic life. Key FeaturesAtmosphere: Denser than Earth's, primarily nitrogen with methane, creating a thick smog.Liquid Cycle: Features a water-like cycle but with liquid methane/ethane instead of water (clouds, rain, rivers, lakes, seas).Surface: Composed of water ice "rocks" and dunes of organic "sand," with features resembling Earth's landscapes.Subsurface Ocean: Evidence suggests a vast liquid water ocean may exist beneath its icy crust, though recent data suggests slushy ice layers.Temperature: Extremely cold, allowing liquids like methane to remain stable. Exploration & FutureCassini-Huygens: Provided extensive data and images, revealing Titan's complex geology and atmosphere.Dragonfly Mission: A future NASA rotorcraft mission designed to explore Titan's chemistry and habitability. Life PotentialWhile liquid water is deep below, some scientists theorize simple microbial life could exist using fermentation in the hydrocarbon environment, though biomass would be extremely limited. SizeIt's larger than the planet Mercury and the second-largest moon in the Solar System (after Jupiter's Ganymede). Titan

The Moon is Earth's only natural satellite, a rocky body that orbits our planet at an average distance of about 384,400 km (239,000 miles). It formed approximately 4.5 billion years ago from debris after a giant impact with Earth, and its gravitational pull is responsible for ocean tides. The Moon is tidally locked with Earth, meaning the same side always faces us, and it has a solid, cratered surface with a very thin atmosphere (exosphere). Key CharacteristicsOrbit: It takes about 27.3 days to orbit Earth (sidereal period) and about 29.5 days to complete a cycle of phases (synodic period). Gravity: Its gravity is about one-sixth of Earth's. Formation: The leading theory suggests it formed from the debris of a massive impact on the early Earth. Surface: A rocky body with a solid surface covered in craters from impacts. Atmosphere: Has a very thin atmosphere called an exosphere, which is not breathable. Exploration: It is the only celestial body beyond Earth visited by humans, with Apollo astronauts bringing back lunar rocks for study. SignificanceTides: Its gravitational pull is the primary cause of Earth's ocean tides.Stabilization: It helps stabilize Earth's axial tilt, contributing to a more stable climate.