The Inner Solar System is the bustling region encompassing the Sun and the terrestrial planets—Mercury, Venus, Earth, and Mars—along with their moons and smaller bodies like asteroids. This region is characterized by rocky planets with solid surfaces and relatively high temperatures due to proximity to the Sun.
It spans from the Sun to roughly 2.2 astronomical units (AU), where the Asteroid Belt begins.
The term "Inner Solar System" is a descriptive label, distinguishing it from the outer regions beyond the Asteroid Belt. It reflects its position within the Sun’s gravitational influence.
Key events include the formation of the terrestrial planets 4.6 billion years ago from the solar nebula. Frequent meteorite impacts shaped planetary surfaces. Humanity’s exploration milestones, such as the Apollo Moon landings and Mars rovers like Perseverance, highlight its significance.
This region remains a focal point for studying planetary geology and the potential for past life, especially on Mars.
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