Nov 01

What’s Up in the Sky

What’s Up in the Sky – November, 2017

Halloween and Astronomy?

Happy Halloween! This being the first time this column has been published on Halloween, I thought it might be fun to see if there was any connection between the holiday and astronomy. Turns out there is. And it stems from the customs and beliefs of early cultures.

Many Halloween traditions can trace their origins to the ancient Celtic festival of the harvest called Samhain (pronounced sah-win). But the date itself is also significant in an astronomical sense because it is a “cross-quarter date”.

We mark the beginnings of the seasons with what we call equinoxes and solstices, so the autumnal equinox marks the first day of autumn in September, and the winter solstice the first day of winter in December. But the dates roughly half-way between these seasonal boundaries, the cross-quarter dates, were also important to early cultures. (We still celebrate two other cross-quarter dates, Ground Hog day on February 2nd, and May Day on May 1st.)

To the early Celts, however, these dates marked the middle of the seasons, not the beginning, and so winter, the “dark season” actually began on the cross-quarter date approximately half-way between the fall equinox and winter solstice, October 31. This makes sense to me since November is much more winter-like than March and we often think of summer ending on Labor Day.

That’s where Samhain comes in. Roughly translated it means “summer’s end” and was the start of the dark season when everything died and the days grew cold. It was also the Celtic new-year’s eve and great bonfires were lit to keep evil spirits away. It was a time of both celebration and fear, as the light, living summer gave way to the dark, dead winter.

It was also a time of year when the well known star cluster, the Pleiades, reached its highest point in the sky around midnight. To the Celts, the Pleiades opened a path to the other world and when they reached their highest point in the sky, the barriers between the worlds broke down, and the souls of the dead could cross over into the world of the living.

The Full Moon is often associated with Halloween, usually depicted with the silhouette of a black cat or flying witch on her broomstick. Unfortunately, the Full Moon does not always fall on October 31, but it is a common image. This year, though, trick-or-treaters will be able to see an “almost-Full” Moon low in the southeast after dinner.

So I hope your day is somewhat enriched by the knowledge that your celebration has its origins up in the sky.

This month in history:
Nov. 3: The dog Laika is first living creature to orbit Earth, aboard Sputnik 2 – 1957
Nov. 9: Carl Sagan born. – 1934
Nov. 16: Interstellar message broadcast from Arecibo radio telescope – 1974
Nov. 20: Edwin Hubble born – 1889
Nov. 27: First photograph of a meteor shower – 1885
Nov. 30: Ten-pound meteorite strikes and bruises Alabama woman, Elizabeth Hodges-1954