Forums Moon Nasa announcement Neither.

Dr Paul Leyland

00:00 is the first midnight of each day; 12:00 is noon; 24:00 is the second midnight of each day.

00:00, occurring before the sun reaches its highest point the sky (except at the geographic poles), is quite clearly ante meridiem and 24:00 is equally clearly post meridiem.

Yes, I am a pedant.  Guilty as charged.