Emperor Cheng of Han (51 BC 17 April 7 BC) was an emperor of the Chinese Han dynasty ruling from 33 until 7 BC. He succeeded his father Emperor Yuan of Han. Under Emperor Cheng, the Han dynasty continued its growing disintegration as the emperor's maternal relatives from the Wang clan increased their grip on the levers of power and on governmental affairs as encouraged by the previous emperor. Corruption and greedy officials continued to plague the government and, as a result, rebellions broke out throughout the country. Emperor Cheng died childless after a reign of 26 years (both of his sons by concubines died in infancy; one of them starved to death). He was succeeded by his nephew Emperor Ai of Han.

Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. 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 magnetic polarity. Their number varies according to the approximately 11-year solar cycle.

Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km (10 mi) to 160,000 km (100,000 mi). Larger sunspots can be visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge.

Indicating intense magnetic activity, sunspots accompany other active region phenomena such as coronal loops, prominences, and reconnection events. Most solar flares and coronal mass ejections originate in these magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars other than the Sun are commonly called starspots, and both light and dark spots have been measured.