A sunspot is observed by Han dynasty astronomers during the reign of Emperor Cheng of Han, one of the earliest dated sunspot observations in China.

Sunspot

Temporary spots on the Sun's surface

Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite…

Science and technology of the Han dynasty

Many significant developments in the history of science and technology in China took place during the Han dynasty.

Han dynasty

Imperial dynasty in China (202 BC – 220 AD)

The Han dynasty was an imperial dynasty of China established by Liu Bang and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–206 BC) and a warring interregnum known as the Chu–Han Contention (206–202 BC), and it was succeeded by the Three…

Chinese astronomy

Aspect of science history

Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on…

Emperor Cheng of Han

Emperor of Han China from 33 BC to 7 BC

Emperor Cheng of Han, personal name Liu Ao, was an emperor of the Chinese Han dynasty ruling from 33 until 7 BC. He succeeded his father, Emperor Yuan. Under Emperor Cheng, the Han dynasty continued its growing disintegration as the emperor's maternal relatives from the Wang…

May 10

Day of the year

May 10 is the 130th day of the year in the Gregorian calendar; 235 days remain until the end of the year.