Learn what to look for in the night sky with today's Nerdy Curio from Stardate. This weekend, the rising Sun will shine through the long entryway of an ancient structure in Ireland. Known as the Mound of the Hostages, it was built more than 5,000 years ago. It served as a burial space and as a site for ritual gatherings. And one of the gathering dates probably was Imbolc, a Celtic festival day that celebrated the birth of the year’s new lambs.

Imbolc was one of many worldwide celebrations of a cross-quarter day — a day that comes roughly half way between a solstice and an equinox. In many cultures, these dates represented the beginning of a season, not its mid-point.

The February cross-quarter day was a time to celebrate the returning Sun. The days were noticably longer by then, with the promise of even more sunshine to come. The festivities included bonfires and candles — stand-ins for the Sun on the still-long nights.

The date for Imbolc is usually given as February first. The date of the actual cross-quarter day varies, though, depending on the dates of the solstice and equinox. This year, the moment that’s exactly half way between these points comes on February 4th for those in Ireland, and the 3rd for most of us in the United States.

In ancient times, celebrants may have thought they could foretell the weather by the conditions on Imbolc. A cold, clear day meant more winter, while a warm or cloudy day suggested that spring was at hand. That custom is still observed today — as Groundhog Day.

Script by Damond Benningfield

Aired February 2, 2018

All Stardate content is available at stardate.org