A disco ball
, mirror ball
, glitter ball
, or ball mirror
is a roughly spherical
object that reflects light directed at it in many directions, producing a complex display. Its surface consists of hundreds or thousands of facets
, nearly all of approximately the same shape and size, and each having a mirrored
surface. Usually it is mounted well above the heads of the people present, suspended from a device that causes it to rotate
steadily on a vertical axis
, and illuminated by spotlights, so that stationary viewers experience beams of light flashing over them, and see myriad spots of light spinning around the walls of the room.
What are now called "disco balls" were first used in nightclubs in the 1920s. An early example can be seen in the nightclub sequence of Berlin: Die Sinfonie der Großstadt, a German silent film from 1927. In the 1970s, these devices were a standard accompaniment to disco music, and by the end of the 20th century, the name "disco ball" had largely eclipsed the earlier names that had been applied to the object.
Miniature disco balls are sold as novelties and used for a number of decorative purposes, including dangling from the rear-view mirror of an automobile or Christmas tree ornaments.
With the appearance of infrared networks, disco balls have found a new application, as a method of dispersing the infrared signals.
The world's largest rotating disco ball is situated in the ABC Nightclub in Glasgow, Scotland.
Pink Floyd used a disco ball on their 1987 and 1994 world tours. The disco ball used on the 1987 tour was somewhat larger than normal but nowhere near as large as the disco ball used on the 1994 tour. This particular disco ball is one of the largest in the world. 4.9 metres in diameter, it rises to a height of 21.3 metres before opening to a width of 7.3 metres, revealing a 12 kilowatt Phobeus HMI lamp. Both can be seen on the video of each tour: "Delicate Sound of Thunder and "P*U*L*S*E" during the song "Comfortably Numb".
Madonna used a 2-ton disco ball that was embellished by 2 million dollars' worth of Swarovski crystals for her Confessions Tour in 2006.
Disco balls in architectural design
The observation deck of the Fernsehturm Berlin
resembles a disco ball.