Besides ice, dust, and gas, comets carry a lot of baggage. To many people throughout history, comets were seen as portents of doom, divine omens of some terrible event soon to occur. In the upper right corner of this part of the 11th-century Bayeux Tapestry, for example, the appearance of Comet Halley in 1066 supposedly foretold the overthrow of England’s King Harold by William the Conqueror at the Battle of Hastings. More recently, astronomers have viewed comets as potential bringers of life. Chock full of water ice and organic compounds, comets raining down on Earth early in the solar system’s history could have provided much of the material needed to kick-start life.