Hypnos comes from the name of his Latin counterpart, Somnus. (in- "not" + somnus "sleep"), as well as a few less-common words such as "somnolent", meaning sleepy or tending to cause sleep and hypersomnia meaning excessive sleep, which can be caused by many conditions (known as secondary hypersomnia) or a rare sleep disorder causing excessive sleep with unknown cause, called Idiopathic Hypersomnia. 3D model of "Bronze head of Hypnos" via laser scan of a cast of British Museum's bronze. Hypnos In Greek mythology, Hypnos (; , "sleep") is the personification of sleep; the Roman equivalent is known as Somnus. In the
14827 Hypnos the nucleus of an extinct comet that is covered by a crust several centimeters thick that prevents any remaining volatiles from outgassing. "Hypnos" is an assumed carbonaceous C-type asteroid. As of 2018, no rotational lightcurve of "Hypnos" has been obtained from photometric observations. The asteroids rotation period and spin axis remains unknown. It has a low brightness amplitude of 0.05 magnitude which indicates that the body has a rather spheroidal shape. According to the NEOSurvey carried out by NASA's Spitzer Space Telescope, "Hypnos" measures 520 meters in diameter and its surface has an albedo of 0.22 based on an absolute