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Fig. 1 - Buzz Aldrin demonstrates locomotion while an object appears to bounce across the lunar surface behind him. (NASA: video downlink 110::14:03, et seq.)

In the Apollo 11 video you can see someone kicking a soda bottle across the surface behind the astronaut.

In Fig. 1 Buzz Aldrin is demonstrating various methods of walking on the lunar surface. He walks toward the camera using the typical Apollo astronaut lope. He will later demonstrate the "kangaroo hop". The object, which is more apparent in the video than in these still images, bounces two or three times and then disappears from sight.

The video can be downloaded from the NASA public affairs office. (MPEG, 8 MB) The frames in Fig. 1 are taken beginning 23 seconds into this clip.

The object in the frame is not actually a physical object. It is the highlight on Aldrin's visor reflected in a peculiar way inside the television camera lens. As Aldrin lopes across the frame from right to left, the object bounces from left to right reflected through the optical center of the lens. The technical term for this is catadioptrism, but photographers usually call it "ghosting".

Fig. 2 - The same frames as in Fig. 1 with guide lines to emphasize the reflection. The pink dots represent the visor highlight and the "bottle"; the yellow line joins them. The light blue lines identify the center of the image. (NASA: video downlink 110::14:03, et seq.)

Fig. 2 illustrates the geometry more closely. In this particular mode of catadioptric reflection, bright spots appear to reflect radially through the center of the image. The diagonal blue lines help locate the center of the photo by connecting the diagonally opposite corners. This will closely approximate the optical axis of the lens. The pink dots are placed on the "bottle" and helmet visor, respectively. The yellow line connects them. Note that the yellow line always passes through the center of the image, and that the pink dots are always equidistant from the optical axis. This is unmistakable evidence of catadioptrism.

Read more about the Coke bottle story here.

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