Comet Wild 2 is a periodic comet that orbits the Sun approximately every 6.5 years. It was discovered in 1978 by astronomer Paul Wild and is notable for its close approach to Earth and its bright appearance. The comet's nucleus is estimated to be about 3 kilometers in diameter, and it is composed of ice, dust, and other organic materials. In 2004, the NASA spacecraft Stardust flew by Comet Wild 2, collecting samples of its dust and particles. These samples were returned to Earth in 2006, providing valuable insights into the early solar system and the building blocks of planets. The study of Comet Wild 2 has helped scientists understand the composition and behavior of comets.