Pioneer plaque

The Pioneer plaques are two golden plates, which are mounted on board of the two interstellar space probes Pioneer 10 and Pioneer 11. The plaques were made ​​in 1972 in the hope that any intelligent extraterrestrial life forms could, therefore, of the human race and its position in the universe, even if the probability is extremely low.

The plates consist of aluminum and are coated with gold. They are 229 mm × 152 mm and 1.27 mm thick.

The most striking figure on the plaque are a man and a woman. As the schematic drawings were published at that time, broke out in the U.S. a heated discussion about whether one may represent the human genitals so openly or not. Some scientists gave further be remembered that the man's hand in greeting erect could be misunderstood by aliens erroneously as an aggressive gesture.

In the background can be seen the same scale the silhouette of the Pioneer probe. To the left of the position of the sun relative to 14 pulsars and the center of the Milky Way is coded. Below is a representation of our solar system with eight planets and the dwarf planet Pluto (which at that time still had planet status ) and the itinerary of the spacecraft it. On the upper left is the representation of a hyperfine transition of the hydrogen atom.

A similar message is in its few years later launched probes Voyager 1 and Voyager 2 in the form of golden records Voyager Golden Record.

Prehistory

The fact that the Pioneer spacecraft should carry a message of humanity to himself, was originally proposed by Eric Burgess during a visit at the Jet Propulsion Laboratory during the Mariner 9 mission. He turned therefore to Carl Sagan, who in 1971 co-organized a conference in Yerevan about possible communication with extraterrestrial life forms and was thrilled by the idea. NASA agreed to the project and had three weeks to prepare a message. Sagan created together with Frank Drake, the plaque that artistic representations of it were made by Sagan's wife Linda Salzman Sagan.

Symbolism

Hyperfine transition of the hydrogen atom

Top left on the badge is a representation of the hyperfine structure transition of a hydrogen atom. Hydrogen is the most abundant element in the universe. Below the drawing is to see a small vertical line, which represents the number 1 in binary. The angular momentum transfer of the electron of the hydrogen from the state 1 ( spin up ) to state -1 ( spin down ) on the one hand describes a unit of length ( wavelength 21 cm ) and a unit of time (frequency, 1420 MHz). Both units can be used in other representations on the plaque as a benchmark, so this is universal.

Representation of men and women

On the right side of the plaque a man and a woman are shown schematically, standing in front of the probe as a size comparison. Between the two lines, which indicate the size of the woman is in binary notation the number 8 (binary: 1-0-0-0 ). Measured in the unit length of the hydrogen transition (0.21 m ) is given as a height of 8 x 0.21 m = 1.68 m.

The man's right hand raised to represent the benevolence of mankind. It can also indicate a movement of the hand like a friendly wave; also shows the illustration of how the human limbs may be moved. Originally Sagan wanted to show people holding hands, but he soon realized that an extraterrestrial intelligence could possibly understand, that this represents an intelligence rather than as two separate.

The representation of the female genitalia is not very clear, only the pubic mound is visible. Sagan and his wife, who had little time for the completion of the plaque, suspected that NASA had rejected a more detailed representation, and therefore created a compromise to be on the safe side. Another design with a more accurate representation, with a short line as a hint of a vulva was, of John Naugle, the former NASA chief scientist, rejected and deleted.

Carl Sagan himself wrote:

"The decision to omit this line, so once, because even in the ancient representation of people of the Greeks, this line was omitted. But there was another reason: We wanted the badge must submit with Pioneer 10. Looking back, we had condemned the hierarchical structures of NASA as puritanical as they are in truth. In the many discussions I had with NASA employees, up to the head of the National Aeronautics and Space Administration and the Scientific Advisor to the President, I had never heard a prudish or narrow demurrer, rather I found really great support. "

Relative position of the sun

The drawing center left represents the position of the sun compared to the center of the galaxy ( Milky Way ) and 14 pulsars dar. 15 lines to go from the same origin, with 14 lines have a corresponding binary number. These numbers indicate the rotational period of pulsars at ( frequency at which it emits radiation). Since the pulsar change their frequency over time ( this decreases), one can calculate the data about the starting of the probe. The length of the line indicates in each case the relative distance between the sun and Pulsar. A tick mark at the end of each line indicates the Z coordinate of the Galactic coordinate system. If the plaque is found, not all pulsars are visible from the location in space from. That is why so much information was given as possible, even if the information is largely redundant. This allows the determination of our sun by means of triangulation, even if only a few pulsars should be visible.

However, an indication is misleading. At the time of the frequency of pulsars " 1240 " was ( now called the " J1243 - 6423 " ) specified by 0.388 seconds, which is only three significant digits, and thus are not very accurate. On the plaque, the value is specified with 100000110110010110001001111000. A 10 binary digits rounded value ( 100000110100000000000000000000 ) would have provided an indication of the uncertainty. The affected pulsar is indicated by the long line that runs down the right. The long horizontal line that passes between people, shows the distance between the sun and the center of the Milky Way.

Solar system

On the plaque At the bottom is a schematic illustration of our solar system. Similarly, the spacecraft is shown a curve (trajectory ) indicates the way out of the probe past the Jupiter and eventually out of the solar system. Both Pioneer spacecraft (10 and 11) carry the exact same badge. Thus, the badge of the Pioneer 11 probe is inaccurate, since these also flew past Saturn and not only on Jupiter. The entire course shown and the target area thus differ significantly from reality.

The rings of Saturn can also be helpful in the identification of the solar system. The rings around the planets Jupiter, Uranus and Neptune were not known at the time of plaque creation. In addition, Pluto at that time was still one of the planets of our solar system. In 2006, however, he was demoted by the International Astronomical Union to a dwarf planet, since 2008 he is only a Plutoid.

The binary numbers in the planet give the relative distance from the sun (on the plaque are the distances for better visualization of the planets are not to scale). The counting unit here is one tenth of the orbit of Mercury.

Silhouette of the spacecraft

Behind the two men is as a benchmark the silhouette of the spacecraft located so that it is possible with their help derive the size of the people and all the other sizes. These are all well as an indication of the hydrogen definition (see above ) is present, therefore the probe and scale is not the only way to determine the units.

Criticism

Critics claim that the representations on the plaque are too anthropocentric and very difficult to understand, especially by any other life form. The plaque was created with the aim of as many important information to accommodate a very small space, there has been less attention to readability and comprehensibility. Many researchers, where the plaque was shown, could not correctly interpret all the information.