Bear in mind that the major garbage patches can be dense enough to cover the surface from horizon to horizon: http://www.nationalgeographic.org/encyclopedia/gre

Bear in mind that the major garbage patches can be dense enough to cover the surface from horizon to horizon: http://www.nationalgeographic.org/encyclopedia/great-pacific-garbage-patch/ http://www.nationalgeographic.org/encyclopedia/great-pacific... It's still just bobbing trash, nothing like an "island", but we're not always just talking about a few grams per square kilometer.