Ship Tracks (IMAGE) University of Connecticut Caption Ship tracks form when very small, airborne particles emitted in the exhaust of large ships (and airplanes) attract water molecules, acting as 'seeds' (or 'cloud condensation nuclei') for clouds. Continued accumulation of droplets on the cloud condensation nuclei forms the thin, streaky clouds pictured in this image. "This is why you often see a trailing track of clouds following ships," he says. "They call those ship tracks." Credit NASA Photo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.