Mercury is the closest planet to the Sun and also the smallest in our solar system. Despite its small size—just slightly larger than Earth's Moon—Mercury is a planet full of extremes. Because it is so close to the Sun, it experiences scorching temperatures during the day, reaching up to 430°C (800°F), while at night, without an atmosphere to trap heat, temperatures can plummet to -180°C (-290°F). This dramatic difference makes Mercury one of the most fascinating and harshest planets to study.

Mercury has a rocky surface covered in craters, much like the Moon, caused by billions of years of collisions with asteroids and comets. It has almost no atmosphere, which means there is no weather, no wind, and no protection from space debris. One of the most interesting things about Mercury is its orbit—it travels around the Sun faster than any other planet, completing one full orbit in just 88 Earth days. That’s why it's named after Mercury, the swift-footed Roman messenger god. Despite its proximity to the Sun, Mercury is not the hottest planet in the solar system—that title belongs to Venus, thanks to its thick, heat-trapping atmosphere.

In recent years, missions like NASA’s MESSENGER spacecraft and the upcoming BepiColombo mission by ESA and JAXA have provided valuable information about Mercury’s composition, magnetic field, and surface features. Though small and often overlooked, Mercury helps scientists understand the early formation of our solar system and the conditions that shape rocky planets like our own.