“Hello from the children of planet Earth.”
Nick Sagan, son of the renowned astronomer Carl Sagan, greets outer space on the Voyager Golden Records. The Voyager Golden Record isn’t just a collection of different languages but is a time capsule sent into the vast universe to convey who we are.
The Voyager Golden Record: An Interstellar Message from Earth
In 1977, NASA launched two spacecraft, Voyager 1 and Voyager 2, to explore the outer planets of our solar system. Their mission was to collect data about Jupiter, Saturn, Uranus, and Neptune by examining their magnetic fields, atmospheres, rings, and moons. Each spacecraft carried a special golden message: a 12-inch gold-plated copper phonograph record known as the Voyager Golden Record. The two identical disks were intended to share our world’s story with extraterrestrial civilizations, achieving humans’ long desire to reach out to the distant, unknown world.
How is Earth depicted?
The Voyager Golden Record is a special artwork that demonstrates Earth’s diversity. It includes 115 images representing human and natural life, as well as chemical diagrams demonstrating humanity’s scientific advancement. An array of natural sounds such as the calls of whales, the sound of rain, and the sound of a heartbeat is accompanied by human-made sounds like laughter, footsteps, and greetings in 55 ancient and modern languages.
How Would Aliens Decipher the Voyager Golden Record?
NASA has never officially confirmed the existence of extraterrestrial life; however, the Golden Record was created with the hopeful belief that an advanced civilization exists and possesses enough scientific knowledge to possibly decode its contents.
But how can creatures on distant planets actually understand our message? The cover is engraved with visual instructions explaining how to play the record. The instructions and the content are encoded in simple binary numbers, 0 and 1, represented by a horizontal and vertical line respectively. An advanced civilization would be able to convert these binary numbers into decimal numbers, which can then be translated into seconds using the hydrogen atom diagram drawn in the corner of the record.
Hydrogen is the most abundant and simplest element in the universe, which makes it apt to serve as the key to the record. Also, the diagram with lines and “1” shows the transitions of the two lowest energy states of hydrogen. This transition emits electromagnetic waves at a specific frequency of 1420 MHz, and since 1 Hz is one cycle per second, this frequency can be used as a universal reference clock.
By taking the inverse of the frequency, aliens can easily calculate the basic unit of time, which is about 0.704 nanoseconds. This can be used to decode the other information on the cover, such as the total length of the content and the playback speed. The cover also includes a pulsar map in the bottom left corner—a diagram locating our solar system’s Sun in the universe relative to 14 known pulsars, or rapidly rotating neutron stars.
Once the aliens potentially figure out the playback speed using this fundamental unit of time, they would then finally play the record and learn some essential information about Earth. Images, however, whose data is stored on the second side of the record, need to be decoded into “viewable form” by translating the visual instruction specifically for playing images. Based on the reference clock and the instruction in the upper left corner of the cover, advanced civilizations can determine that the audio wave should be interpreted every 8 milliseconds. On Earth, the Voyager Golden Record can be played at 16.5 revolutions per minute, and software programs can decode the images.
Conclusion
“This is a present from a small, distant world, a token of our sounds, our science, our images, our music, our thoughts, and our feelings. We are attempting to survive our time so we may live into yours.” — President Jimmy Carter
Today, after more than 45 years passed, both Voyager 1 and Voyager 2 are the only spacecraft beyond the solar system in interstellar space. The Voyager Golden Record is not just a scientific artifact, but a gift of peace and curiosity from Earth, reflecting humanity’s determination to communicate with the unknown.
The golden message might drift into our universe forever, but no matter the end of its journey, the record will always carry the recorded message of humans’ hope to build a better world and to leave a part of us in space.