The planet closest to the sun is Mercury. Due to its proximity, Mercury experiences extreme temperature fluctuations, ranging from scorching heat during the day to freezing cold at night. The planet has a thin atmosphere that cannot retain heat, contributing to these drastic temperature variations. Mercury completes an orbit around the sun approximately every 88 Earth days, making its year significantly shorter than ours. Despite being the smallest planet in our solar system, Mercury holds great interest for scientists studying planetary formation and the characteristics of rocky planets. Its surface is heavily cratered, resembling the moon's landscape.