Well, it's a panorama. If the light source (sun) is located in the 'missing' portion of the panorama, then you would expect the different shadows on either side of the missing bit. This is consistent with the apparent shadow under the buggy.
Here's a terrestrial example of the madness that happens to shadows (and geometry in general)with panoramas. It's partly less obvious on the moon since it lacks familiar references.
Here's a terrestrial example of the madness that happens to shadows (and geometry in general)with panoramas. It's partly less obvious on the moon since it lacks familiar references.
[http://commons.wikimedia.org/wiki/File:Bundeena-pier-360-pan...]