astronomical timekeeping

Astronomical timekeeping is based on Earth's movements relative to celestial objects. The most common system, Coordinated Universal Time (UTC), uses signals from atomic clocks but is synchronized with Earth's rotation and orbit. Earth's rotation defines a day, while its orbit around the Sun determines the year. Historically, days were divided into 24 hours based on Earth's rotation. To keep time aligned with Earth's orbit (the solar day), leap seconds are occasionally added or removed. This ensures our clocks match the position of the Sun in the sky, maintaining consistency in timekeeping with astronomical phenomena.