Ship fumes create streaky white clouds visible from space.
Since 1965 scientists have observed unusual cloud lines that crisscross over the ocean in certain satellite images. Researchers initially speculated that aircraft, missiles, or even natural patterns of air circulation might have caused the oddly shaped clouds to form. But ultimately seafaring ships proved to be the culprits; specifically tiny particles found in the exhaust that billows from their smokestacks. The streaky clouds, called ship tracks, are found throughout the world's oceans. They form in the same manner as marine clouds, which are made of individual cloud droplets created when water condenses around sea salt and other airborne particles known as aerosols. Ship fumes, however, inject extra particles into the air that boost the overall number of particles and cause an abundance of small, more reflective cloud droplets to form. The result: lines of unusually bright and narrow clouds such as those seen in the video below.