Mercury is the smallest planet in our Solar System

Mercury is the smallest planet in our Solar System, yet it hides a massive secret beneath its surface. Despite its size, Mercury’s iron core takes up an astonishing 85% of its radius — a much larger proportion than any other planet. This dense core makes Mercury incredibly heavy for its size and offers clues about the violent history of our early solar system. Orbiting so close to the Sun, Mercury’s surface is scorched by intense heat, but its core reveals the planet’s fiery past and complex interior.