boeing247 wrote on Aug 12^th, 2011 at 9:26pm:

John007 wrote on Aug 12th, 2011 at 8:42pm: i know its weird any body know why it does this :-? :-? :-? Ah, a science lesson!  ;D It's because the camera on the satellite captures each color separately. The three primary colors of light (not color, there's a difference) are Red, Blue, and Green. I'm not sure what that fourth channel is, but I'm pretty sure it's the alpha channel (which generally refers to transparency and probably shading). The camera captures them in rapid succession, and the overlay creates the image. Notice how where the R, G, and B channels overlap, it's white (which is the color of the plane)? Now, as you may know, if you combine all the colors of light (R, G, and B, since all other colors are just mixtures of those three), you get pure white light. (If you look through a prism, the white light gets split into these colors again and creates a rainbow.) But why is the plane all messed up? Because it's moving very fast. Satellite imagery is generally of static objects (houses, trees, etc...), so this is generally not a problem, but when a plane is captured by a satellite with a low shutter speed, it is broken down into the four channels which make up the picture.

the fourth channel is ether the alpha or yellow