From what I understand, satellite cameras take a few layers of a photo within a fraction of a second. The layers are merged to produce the final image.
Between the speed of a very fast moving item, such as a jet, and the speed and direction of the satellite, a ghost image can be seen on one of the photo's layers.
"The satellite that takes many of Google Earth Satellite based (high resolution) images is QuickBird it employs linear array CCDs. One set takes panchromatic images (grey scale) and the second set takes multi spectral images (MSI). The MSI imager is mounted in different physical location on the satellite so its images are acquired later in time.
These images are time re-aligned on the ground on the assumption that there are no moving objects in the field of view. As a consequence any moving object will have a colored image that appears ahead of the moving object and at lower resolutions. These images are double exposures."
Airplanes - Civilian - In Flight - Large jets 
Between the speed of a very fast moving item, such as a jet, and the speed and direction of the satellite, a ghost image can be seen on one of the photo's layers.
These images are time re-aligned on the ground on the assumption that there are no moving objects in the field of view. As a consequence any moving object will have a colored image that appears ahead of the moving object and at lower resolutions. These images are double exposures."
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