BETA
The exact length of a year and how we measured it
A tropical year is the precise time it takes Earth to complete one orbit around the Sun, measured from equinox to equinox. This journey takes 365 days, 5 hours, 48 minutes, and 45 seconds. Because this is not a whole number, any calendar with exactly 365 days will slowly drift out of sync with the seasons.
Chapter 1
The illusion of a stationary Earth
Chapter 2
The sun takes center stage
Chapter 3
The math of a year
Chapter 4
Solving the calendar puzzle
Ch 3 · The math of a year
futura Earth Orbit Calendar
The Earth spins 'round the Sun, you see, (Oh-oh, not perfectly!) Five hours and forty-eight more, (Yeah-yeah, that's what calendars are for!)
futura Twice a year, the Earth's tilt aligns perfectly with the Sun, producing equal day and night worldwide.
Fun Fact
Earth's speeding orbit: Earth travels around the Sun at a blistering speed of about 67,000 miles per hour.
futura Earth's axial tilt of 23.5 degrees causes the changing seasons and the extreme days of the solstices.
Glossary
leap year (noun)
A calendar year containing an extra day to keep it synchronized with the astronomical or seasonal year. Julius Caesar implemented this quadrennial correction in 45 BC to stabilize the Roman calendar.
A calendar year containing an extra day to keep it synchronized with the astronomical or seasonal year. Julius Caesar implemented this quadrennial correction in 45 BC to stabilize the Roman calendar.