The Formation of the Moon: The exact process of how the Moon formed alongside Earth is still a subject of scientific investigation, with hypotheses ranging from a giant impact to capture theory.
The Existence of Water on Mars: The presence of water on Mars, in the form of ancient riverbeds, polar ice caps, and seasonal flows, raises questions about its history and the potential for past or present life.
The Enigma of Enceladus: Enceladus, a moon of Saturn, exhibits geysers of water vapor erupting from its south pole, suggesting the possibility of a subsurface ocean and potential for life.
The Mysteries of Venus: Venus is shrouded in a thick atmosphere, making it difficult to study its surface. The unknown origin of its extreme greenhouse effect and the possibility of active volcanism are still debated.
The Origins of Jupiter's Great Red Spot: Jupiter's Great Red Spot, a gigantic storm that has persisted for centuries, continues to puzzle scientists regarding its formation, longevity, and dynamics.
The Rings of Saturn: Despite extensive study, the exact origin and age of Saturn's magnificent rings are not fully understood. Questions remain about their composition, stability, and mechanisms for their formation.
The Puzzling Moons of Uranus: Uranus has several unusual moons, including Miranda with its varied terrain and Ariel with its mysterious tectonic features. Understanding their geological history remains a mystery.
The Tilt of Uranus and Neptune: Uranus and Neptune have extreme axial tilts, causing seasons that differ greatly from those on Earth. The cause of their tilts and the mechanisms behind them are still not definitively known.
The Oceans of Europa and Ganymede: Jupiter's moons Europa and Ganymede are believed to have subsurface oceans, potentially harboring conditions favorable for life. The extent of these oceans and their characteristics are subjects of scientific exploration.
The Origin of the Asteroid Belt: The formation and evolution of the asteroid belt between Mars and Jupiter remain uncertain. The presence of dwarf planet Ceres and numerous asteroids raises questions about the initial conditions and subsequent dynamical processes.