In units of the wavelength of the hyperfine transition of hydrogen this means 8 × 21 cm = 168 centimetres (66 in). Between the brackets that indicate the height of the woman, the binary representation of the number 8 can be seen (1000). On the right side of the plaque, a nude man and woman are shown in front of the spacecraft. Figures of a man and a woman Figures of a man and a woman Both units are used as measurements in the other symbols. Below the symbol, the small vertical line-representing the binary digit 1-specifies a unit of length (21 cm) as well as a unit of time (0.7 ns). Light at this frequency has a vacuum wavelength of 21.106 centimetres (8.309 in) (which is also the distance the light travels in that time period).

The spin-flip transition of a hydrogen atom's electron has a frequency of about 1420.405 MHz, which corresponds to a period of 0.704 ns. Symbolism Hyperfine transition of neutral hydrogen Hyperfine transition of neutral hydrogenĪt the top left of the plaque is a schematic representation of the hyperfine transition of hydrogen, which is the most abundant element in the universe.

Mean depth of engraving: 0.015 inches (0.381 mm).

Material: 6061 T6 gold-anodized aluminium.

In May 2017, a limited edition of 200 replicas engraved from the original master design at Precision Engravers was made available in a Kickstarter Campaign, which also offered laser-engraved replicas. The first plaque was launched with Pioneer 10 on March 2, 1972, and the second followed with Pioneer 11 on April 5, 1973. īoth plaques were manufactured at Precision Engravers, San Carlos, California. Additional artistic contributions were made by Jon Lomberg. Together with Frank Drake he designed the plaque, and the artwork was prepared by Linda Salzman Sagan, who was Sagan's wife at the time.

NASA agreed to the plan and gave him three weeks to prepare a message. Sagan was enthusiastic about the idea of sending a message with the Pioneer spacecraft. He approached Carl Sagan, who had lectured about communication with intelligent extraterrestrials at a conference in Crimea. The original idea, that the Pioneer spacecraft should carry a message from mankind, was first mentioned by Eric Burgess when he visited the Jet Propulsion Laboratory in Pasadena, California, during the Mariner 9 mission. The plaques were attached to the spacecraft's antenna support struts in a position that would shield them from erosion by interstellar dust. The Pioneer 10 and 11 spacecraft were the first human-built objects to achieve escape velocity from the Solar System. The plaques show the nude figures of a human male and female along with several symbols that are designed to provide information about the origin of the spacecraft. The Pioneer plaques are a pair of gold- anodized aluminum plaques that were placed on board the 1972 Pioneer Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 is intercepted by intelligent extraterrestrial life.

Gold woman with thumbs up drawing