Visualizing Cycles – The Lunar Cycle
Visualizing Cycles – The Lunar Cycle

Visualizing Cycles – The Lunar Cycle

I find Space facsinating and I alway enjoy creating data visualizations about Space. I recently explored the process of visualizing cycles as part of the monthly challenge over at storytelling with data. To take part in the challenge I created a cluster of pie charts to visualize the Lunar Cycle for January 2022.

The Lunar Cycle

It takes 28 days for the Moon to go from a New Moon phase to the next New Moon phase and begin a new cycle. New Moon is the phase when the Moon is positioned between the Earth and the Sun. In that moment the Sun shines on the side of the Moon that cannot be seen from Earth, also known as the dark side of the Moon. But during a New Moon phase it is the side that we can see from Earth that is completely dark and we don’t see the Moon in the sky. But as the Moon starts the 28-day cycle around Earth and the Sun shines on parts of the visible side we start to see little parts of the Moon in the sky. If less than half of the side of the Moon is light in the sky we call it a Crescent Moon. Until the Moon reaches the First Quarter – half of the surface is dark and the other half is light. Then the Moon becomes a Gibbous Moon, meaning more than half of its surface is light and seen in the sky. It takes between 5 to 7 days for the New Moon to reach the First Quarter and another 5 to 7 days to reach the Full Moon phase. During Full Moon, the Moon faces the Sun with the visible side and in that moment the entire surface is visible. We see a beautiful ful circle in thes sky. Between New Moon and Full Moon the phases are known as Waxing Moon. After the Full Moon phases, it takes between 5 to 7 days for the Moon to reach the Final Quarter phase and then another 5 to 7 days to reach the end of the cycle and begin a new one.

Visualizing the Lunar Cycle

Pie charts are not loved by data visualization designers. They however are the preferred choice for many business professionals. I also think pie chart serve a purpose. And in the case of visualizing the Lunar Cycle, pie charts are the perfect choice to represent the Moon. In this visual I have created a cluster of pie charts in Flourish. I start with a dark circle and each pie chart that comes after starts to show the percentage of the visible part of the surface of the Moon. I used dark blue and yellow to represent the dark and light surface of the Moon during the cycle. Full Moon is a yellow circle, a pie chart where one variable is 100% and the other 0%. Then the cycle begins again with the next New Moon.

In this example I am using the Lunar Cycle phases for January 2022. Sometimes it takes less and sometimes more days for the Moon to go from New Moon to the First Quarter, from the First Quarter to Full Moon, from Full Moon to the Last Quarter and from the Last Quarter to the next New Moon. This is because while the Moon travels around Earth, Earth travels around the Sun and its own orbit. This way phases of the Moon vary.

Data Viz for Kids

I created a simplified excercise for kids to create a diagram of the Moon phases using paint, paper and markers. You can check it out on Data Viz for Kids – Moon Phases Diagram.