When comets draw near to the Sun, intense heat causes their surface materials to vaporize. This process creates the striking tails for which comets are well known. As the comet gets closer, the sublimation of ice and other materials produces gas and dust that stream away from the nucleus, forming the visual phenomenon we observe from Earth. This interaction with solar radiation and solar wind is essential in shaping a comet's tail.

Bill Bryson's "A Short History of Nearly Everything" explores a variety of scientific topics, including the behavior of comets. It highlights how the relationship between comets and the Sun results in these captivating displays, allowing us to appreciate the dynamic processes occurring in our solar system. The transformation of comets as they approach the Sun serves as a reminder of the intricate workings of the universe.