The
Pioneer plaque contains drawings of two humans and our place in the galaxy. The spacecraft is drawn behind a human male and female for scale. The solar system appears along the lower edge. Each planet and Pluto is shown with a binary number indicating the average distance from the Sun. Distances are listed in units of 1/10th the Mercury distance. The diagram in the upper left shows atomic hydrogen, by far the most abundant element in the universe. It shows a hydrogen atom undergoing a shift in its electron energy level. This change emits electromagnetic radiation at a wavelength of 21 centimeters (8 inches), and is the most common such emission in the universe. This is used as a frequency and distance scale represented by the binary number 1. Converging lines in the left show the position of the Sun relative to 14 pulsars in the Milky Way and the center of the galaxy. Pulsars are very dense remnants of exploded giant stars, and they rotate at very stable frequencies. The frequency of each pulsar is listed in binary numerals relative to the frequency of hydrogen emission. The average human height, of approximately 168 centimeters (or 5 feet 6 inches), is listed on the right-hand side as the binary number 8 (1000, shown as | - - - ), relative to the 21 centimeter (8 inch) wavelength of hydrogen emission. Leaving the Solar System Besides Pioneer 10 and 11, three other spacecraft have reached the Sun's escape velocity and are currently moving out into the stars: Voyager 1, Voyager 2, and
New Horizons.
by Paul Ceruzzi, Nat. Air and Space Museum/Smithsonian |
Read more:Image: Smithsonian
[ed. Obviously for aliens much smarter than I am. Designed by Carl Sagan and Frank Drake (drawn by Linda Salzman, Mr. Sagan's second wife).]
