"This is simple English," said Clive Neal, a lunar authority at the Department of Civil and Environmental Engineering and Earth Sciences at the University of Notre Dame in Indiana.
"The name of Earth's only natural satellite is 'the Moon' — it is a proper noun, so it is spelled with a capital 'M.' End of story," Neal told Space.com.
If organizations profess to follow the English language, the Moon always has a capital 'M,' he added.
"Otherwise, they follow a language I am not familiar with," Neal said. "The Associated Press (AP) does not follow the English language (note: no capital letters!)," he said. "Phobos
is a natural satellite of Mars — a moon. The Moon is the only natural satellite of Earth — it is a moon of Earth called the Moon."
Quite correct, "End of story" as he says. Associated Press are just plain wrong.