The Sentinel (short story)
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"The Sentinel" is a science fiction short story by British author Arthur C. Clarke, written in 1948 and first published in 1951 in 10 Story Fantasy as "Sentinel of Eternity". Its plot and ideas influe
First appearance in 10 Story Fantasy, 1951.
Geology of the Moon
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The geology of the Moon is the structure and composition of the Moon, which is quite different from that of Earth. The Moon lacks a true atmosphere outside of a sparse layer of gas. Because of this, t
The Sentinel (short story)
…The Lost Worlds of 2001 (1972). The story is set in 1996 (at the time of writing, several decades in the future). The narrator, Wilson, is a veteran selenologist on an expedition to explore the lunar surface. He comes across a mysterious pyramidal structure, surrounded by an "invisible shield" which blocks all…
False-color image of the Moon taken by the Galileo orbiter showing geological features. NASA photo
The same image in true color.
Ancient rift valleys – context
Ancient rift valleys – closeup (artist's concept)