chunk: The menace in this story consists of dust from the tail of a comet. It consists of a colloid, analogous to smoke, that incorporates an unknown transuranic element. That element has a great affinity for metal surfaces and it weakens their surface tension, thereby enabling rapidly moving parts to cold weld themselves into solid rigidity.In the town of Mayfield high-school senior Ken Maddox is among the people fascinated by a giant comet whose path is just grazing Earth’s orbit. For the next four months Earth will float within the comet’s tail and on the first night of that sojourn Ken’s car and others begin to have problems with overheating. The next day almost all of the cars in Mayfield and other cities across the country have overheated and then refused to start. Soon all machinery is seizing up, its moving parts cold welded to each other. Because the effect is happening all over the world, people begin blaming the comet.