Seven Days a Week

Did you ever wonder why we have seven days in a week? As it turns out the seven day week is based on the moon and not the sun. There are 29 days to the moons cycle which breaks down into 4 seven day periods with 1 day of what is called a New Moon (also called the Dark Moon) and is not visible as there is no sun light is being reflected to earth from its surface.

  • Day 1 – 7 is the Waxing Crescent and on day 7 will reach the Half Moon phase.
  • Day 8 – 14 the moon moves from the Half Moon to the Full Moon and we can see the entire illuminated portion of the moon.
  • Day 15 – 21 It moves from the Full Moon to the Third Quarter also called a “Half Moon”, but the illuminated part is opposite of the First Quarter.
  • Day 22 – 28 The moon enters its last Quarter and moves from the Half Moon to the New Moon.
  • Day 29 is called the New Moon and the Moon is not visible for one night and then will start its cycle over again.

It is kind of funny that we use two systems to keep time. The first would be the obvious system, the Sun. We measure our seconds, minutes, hours, days, and years with the sun but we use the Moon to measure our weeks and months. That is why we need a leap year every four years to adjust the calendar back into alignment with the Sun and Moon.