Regarding the hours in a day...on earth. Hours were invented by the ancient Egyptians, possibly with influence of the Babylonians. There were 12 hours of day in every ancient Egyptian day, and 12 hours of night. Naturally, the length of the hours changed every day, with the seasons. When picked up by the Europeans in the Middle Ages, the "hours" were kept track of by the local church in similar fashion...for prayer services. Prayer services happened everyday at the same time relative to sunrise/sunset. It's only when clocks were invented that hours were "sundered" from dawn and dusk, and instead made into equal time intervals -> largely because the level of engineering associated with watchmaking could only accomplish so much (at first). Read more about it here: http://www.timezone.com/article.aspx?id=tmachine&articleId=tmachine0004 ed -- Ed Hahn / ehahn at isochronism.com "It don't mean a thing if it ain't got an even swing!"