The science behind the smoke that signals selection of new pope
All eyes are on the Sistine Chapel in Vatican City, where either black smoke or white smoke will emerge to signal whether a new pope has been selected. According to historians, smoke in some form has been used for hundreds of years to indicate the outcome of the papal conclaves. White smoke indicates that a successor has been chosen, while black smoke signifies that no decision has been made and that a revote is required.