our species has been keenly interested in the patterns of the sky for as long as we are aware. Neolithic and Bronze aged Irish are no different. This section outlines some of the data we know they had and used. Note this also tells us they had a fairly complex understanding of maths, we will explore that in other articles.

To define what the stone aged Irish new we need to define a few terms.

Metonic Cycle

This is a feature of lunisolar calendars the 19 year Metonic Cycle of the moon ... that is 19 solar years is nearly exactly 235 lunar months

Synodic Month

aka the Lunar month, this is tracking the phases of the moon as observed from earth roughly 29.5 days.

Neolithic Irish where aware that the lunar "year" did not align with the solar year and calculated this on "calendar stones". These stones define the lunar month as 29 days and show the error with the solar year and express the 235 lunar month long Metonic Cycle.

What did they know?

We cant say for sure but the "calendar stones" we find can be used by modern researchers to calculate the synodic month and Metonic cycle. These bits of information would be critical to build structures aligned to to multiple astronomical events.

So what we can say for sure is that Neolithic Irish builders understood astronomy well enough to build elaborate complexes that demonstrate that knowledge and where abele to disseminate that knowledge across the population and across generations.

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