Autumnal Equinox takes place tonight - what to expect
Summary
Sean Moncrieff and David Moore from Astronomy Ireland discuss the autumn equinox, explaining how Earth's axial tilt creates equal day and night lengths. They explore the historical significance of astronomical alignments, such as Newgrange, and clarify why the scientific start of autumn differs from the arbitrary human calendar. The conversation also covers the upcoming winter solstice, the impact of time zones on the equinox date, and how the approaching darker nights provide ideal conditions for stargazing.
Topics discussed
Introduction to the Autumn Equinox
Scientific definition and timing of the equinox
Critique of the arbitrary human calendar
Newgrange and ancient astronomical alignment
Ancient day counting and agricultural survival
Newgrange construction and early Irish winters
Equal day length and atmospheric refraction
Seasonal daylight changes and solstices
Why the equinox date shifts annually
The Gregorian calendar reform and riots
Time zones and international date confusion
Astronomical definitions and Mars seasons
Educational value and economic impact of science
Astronomy viewing opportunities and upcoming events
Astronomy Ireland resources and sign-off
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