The Great Pacific Garbage Patch, also known as Garbage Island is located between San Francisco and Hawaii. It is in the central North Pacific Ocean. It is currently floating somewhere around the area.
Sizes
The GPGP is never at the surface of the water, it is usually floating just below the water's surface making it impossible for satellites or airplanes to located it. However its estimated size ranges from about 700,000 square kilometers (270,000 square miles) to about 15,000,000 square kilometers (5,800,000 square miles). It is about the size of two Texas. In depth and about 100 feet down in the water.
About 80% of the plastic gathered came from in land plastic thrown into the sea, and about 20% of it come from cruise ships and such who throws things off board. Humans are held responsible (of course). People should pass a law that forbids the use of plastic! The below is a really interesting video.
Characteristics
Most of the garbage collected in the area are plastics, mostly plastic bags. Their sizes vary, some are as small as a human thumb. There are some eco-friendly plastic bags in there, but for them to decompose, they need lots of sunlight. However, because they are in the water, plankton grows on them very quickly and covers all of its surface and taking all of its sunlight, making it very hard for these bags to decompose. So, these plastic requires a great amount of time before fully decomposing. Also, as they decompose, they become smaller and smaller, making it very easy for organisms to swallow them. This would mean finding plastic in our meals.
How they make it there
The garbage thrown from many places of the world flows into a oceanic current that would bring them all at the place where the patch is. The video below is very interesting.