2,000-year-old 'celestial calendar' discovered in ancient Chinese tomb

Wooden slips marked with Chinese characters that relate to the traditional Tiangan Dizhi astronomical calendar.

Archaeologists in China have unearthed a mysterious set of rectangular wooden pieces linked to an ancient astronomical calendar. The artifacts were discovered inside an exceptionally well-preserved 2,000-year-old tomb in the southwest of the country.

Each of the 23 wooden slips is about an inch (2.5 centimeters) wide and 4 inches (10 cm) long and displays a Chinese character related to the Tiangan Dizhi, or "Ten Heavenly Stems and 12 Earthly Branches" — a traditional Chinese astronomical calendar established during the Shang dynasty, which ruled from about 1600 B.C. to about 1045 B.C.