http://www.youtube.com/watch?v=uLrVCI4N67M

he patch extends over a very wide area, with estimates ranging from an area the size of the state of Texas to one larger than the continental United States; however, the exact size is unknown. This can be attributed to the fact that there is no specific standard for determining the boundary between the “normal” and “elevated” levels of pollutants and what constitutes being part of the patch.

http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patchgr