'Blue Moon' Returns to Halloween After 19 Years

A supermoon is visible in the night sky over downtown Seoul on the 31st, where the supermoon, blue moon, and blood moon can be observed at once. Photo by Jinhyung Kang aymsdream@ (unrelated to the article)

[Asia Economy Reporter Junho Hwang] On the 31st, Halloween Day, a 'Blue Moon' will appear for the first time in 19 years. The Gwacheon National Science Museum will commemorate this by conducting a full moon observation and commentary online on the 31st.

'Blue Moon' Arrives on Halloween Day for the First Time in 19 Years

The supermoon, blue moon, and blood moon can all be observed at once on the night of the 31st in the Seoul city sky, where the supermoon is beginning a partial lunar eclipse. Photo by Kang Jin-hyung aymsdream@ (unrelated to the article)

A full moon typically appears three times in one season. However, there are times when it appears four times, and the Blue Moon refers to the third full moon in such cases. It is often mistakenly known as the second full moon in a single month. This misconception originated from a false report published in 1946 by the famous American astronomy magazine Sky & Telescope, which then spread widely.

The origin of the term Blue Moon comes from the idea that there should be only one full moon per month, but an extra one appeared, which was called 'belewe moon' meaning 'betrayers.' Over time, due to phonetic similarity, it changed to 'Blue Moon.' In Eastern cultures, the full moon symbolizes abundance, but in Western cultures, it was considered an ominous sign. Accordingly, a moon that appears twice in one month was combined with the gloomy color blue and called a 'Blue Moon.'

A Blue Moon literally means a blue-colored moon, but it does not actually appear blue. However, it can appear blue when light is scattered by dust caused by wildfires or volcanic eruptions. On average, a Blue Moon occurs every 2 years and 8 months, and a Blue Moon appearing on Halloween Day happens once every 19 years. The next Blue Moon on Halloween Day is scheduled for October 31, 2039.

Enjoying the 'Blue Moon and Halloween Day' at Home

The Gwacheon National Science Museum will broadcast live the Blue Moon on Halloween Day through a camera connected to a telescope at the observatory. Additionally, performers dressed as Halloween characters will explain the meaning and origin of the Blue Moon and Halloween Day. An interview video about the current status and plans of Korea's lunar exploration, as well as the lunar exploration status of various countries worldwide, will be aired. Using a high-sensitivity camera, an astronomy commentator will provide explanations of autumn constellations.

Dr. Jaeil Jo, an astronomer at the Gwacheon National Science Museum, stated, "Although the Blue Moon and Halloween Day do not have significant scientific meaning, we wanted to create an opportunity for families to enjoy the Blue Moon at home during the difficult times of the COVID-19 pandemic."

Detailed information about the online broadcast can be found on the Gwacheon National Science Museum website. The live broadcast will be streamed on the Gwacheon National Science Museum YouTube channel from 8 PM to 9 PM.