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The Context Camera onboard MRO has been discovering new impact sites on Mars, followed up with HiRISE images. Usually these sites are discovered as new dark spots from removal or disturbance of bright dust, but a few show up as new bright spots. These craters may have bright ejecta from exposure of shallow subsurface materials, below a thin dark cover. An alternate theory—that this is a particle size effect—is unlikely because the bright materials are also distinctly redder than surrounding areas, and because ejecta is typically more coarse-grained, which would make the surface darker rather …
