Month: July 2025

GREGORIAN CALENDAR
The modern calendar, introduced by Pope Gregory XIII in 1582, based on the solar year.

JULIAN CALENDAR
A calendar introduced by Julius Caesar, later replaced by the Gregorian calendar.

UNIVERSAL TIME (UT)
A time standard based on Earth’s rotation, used in astronomy and navigation.

ATOMIC CLOCK
The most accurate timekeeping device, using atomic vibrations to measure time precisely.

CHRONOMETER
A precise timekeeping device used for navigation.

GNOMON
The part of a sundial that casts a shadow.

SUNDIAL
A device that tells time by using the position of the Sun’s shadow.

EPOCH
A reference point in time used to calculate celestial positions.

SOLSTICE
The point when the Sun reaches its highest or lowest position in the sky, marking the longest and shortest days of the year.

EQUINOX
The time when day and night are nearly equal in length, occurring in March and September.