Ío is one of the many moons of Jupiter, the largest planet in our solar system. It is known for its striking volcanic activity, making it the most geologically active body in the solar system. Ío's surface is covered with sulfur and sulfur dioxide, giving it a colorful appearance with yellow, red, and white patches. The intense volcanic activity on Ío is primarily caused by the gravitational pull from Jupiter and its other moons, which creates tidal heating. This process generates enough heat to melt the moon's interior, resulting in frequent eruptions and the formation of lava lakes.