June 25 is the Day of the Seafarer, a global event highlighting how much we rely on the maritime industry. Turns out, it’s a whole lot, as ships transport more than 80 percent of global trade. In honor of this occasion, we’re showing a NASA satellite view of ship tracks over the Pacific. And what are ship tracks, you ask? They’re clouds that form around particles in ship exhaust when it hits the damp ocean air. These clouds often stretch in narrow paths as in this image, reflecting ships’ courses. To the seafarers out there (1.5 million, according to the International Maritime Organization), we wish you smooth sailing and a good day at sea.