NASA’s Europa Clipper spacecraft, which will head to Jupiter’s icy moon Europa in October 2024, will carry a laser-etched message celebrating humanity’s connection to water. The message pays homage to past NASA missions that carried similar messages.
As president of Extraterrestrial Messaging Intelligence, or METI International, I helped design the messaging in Clipper along with linguists Sheri Wells-Jensen and Laura Buszard-Welcher, two members of our board of directors. METI International is a scientific organization dedicated to transmitting powerful radio messages to extraterrestrial life.
We collected audio recordings in 103 languages and figured out how we could turn them into waveforms that visually represent those sounds. His colleagues at NASA etched these waveforms into the metal plate that protected the spacecraft’s sensitive electronics from Jupiter’s harsh radiation.
I also designed another part of the message that visually depicts the wavelengths of the components of water because water is crucial to the search for intelligent life in the universe.
Engraving messages on spacecraft is not a new practice, and Clipper’s message fits into a decades-old tradition started by astronomer Carl Sagan.
In 1972 and 1973, two Pioneer spacecraft set out for Jupiter and Saturn, carrying metal plaques bearing scientific and pictorial messages. In 1977, two Voyager spacecraft set out for Jupiter, Saturn, Uranus, and Neptur carrying gold-plated copper phonograph records. These recordings included mathematics and chemistry lessons, as well as music, photographs, the sounds of the Earth, and greetings in 55 languages.
water words
Because water is essential to life on Earth, searching for its presence elsewhere has been key to many NASA missions. Astronomers suspect that Europa, where Clipper is headed, has an ocean beneath its icy surface, making it a prime candidate for the search for life in the outer solar system.
Part of the Clipper message includes the word water in 103 languages. We started with audio files collected online, but then we needed to analyze them and come up with an output that could be engraved on a metal plate. I went back to some of the techniques I used in some of my early psycholinguistic research investigating how emotions are encoded in speech.
The 103 spoken words we recorded represent a global snapshot of linguistic diversity on Earth. The outward-facing side of the clipper plate displays words as waveforms that track changing sound intensity as each word is spoken.
Every person we recorded saying the word “water” on the waveform had a connection to water. For example, the lawyer who contributed to the Uzbek word for water, “suv,” organizes a music festival every year in Uzbekistan to raise awareness about the desertification of the Aral Sea.
“aigua,” the native Catalan word for water, hunts for exoplanets and discovers potentially habitable planets orbiting other stars.
Drake Equation
Clipper’s message also pays homage to astronomer Frank Drake, the father of SETI (Search for Extraterrestrial Intelligence), by bearing the formula that bears his name, the Drake Equation. Using scientific data and some best guess hunches, the Drake Equation estimates the number of extraterrestrial civilizations in the galaxy currently sending messages to the universe.
One widely cited estimate puts the number of these extraterrestrial civilizations at one-tenth of a person’s average lifespan in years. For example, if civilizations survive for a million years, there should be approximately 100,000 civilizations in the galaxy. Even if they last only a century on average, scientists would estimate that there are about 10 of them.
Radio astronomers study the universe by examining the radiation emitted by chemical elements in space. They spend most of their time mapping the distribution of the most abundant chemical in the universe: hydrogen.
Hydrogen emits radiation at a specific frequency, called the hydrogen line, that radio telescopes can detect. During Project Ozma, the first modern-day SETI experiment, Drake looked for artificial signals at the same frequency because he thought scientists on other worlds might recognize hydrogen as universally important and broadcast signals at that frequency.
water hole
As our team developed our water words message, I realized that the message would only make sense if discovered by someone who was already familiar with the content written on the plate. The Drake Equation will only make sense if someone already knows what each of the terms in the equation means.
The Europa Clipper will hit Jupiter or one of its other moons, with Ganymede or Callisto being the leading candidates. But if for some reason the mission changes and it survives this fate, then in the distant future people with a completely different cultural background and different language traditions may be able to bring it back as an ancient artifact thousands of years later.
To make sure we had at least a part of the message that a distant future scientist could understand, I also designed a pictorial representation of the frequency Drake used for Project Ozma: the hydrogen line. We etched this into the Clipper plate along with a frequency called the hydroxyl line.
Hydrogen (H+) and hydroxyl (OH-) combine to form water. Scientists call the frequency range between these lines a “puddle.” The puddle represents a portion of the radio spectrum where astronomers conducted the first SETI experiments.
We imaged the hydrogen and hydroxyl lines in the clipper message using wavelengths. The metal plate also contains diagrams showing what hydrogen and hydroxyl look like at the atomic level.
We hope that future chemists will recognize these chemical compounds as components of water. If they do this, we will have succeeded in conveying at least a few basic scientific concepts across time, space and language.
Waveforms allow our team to connect messages on both sides of the Clipper plate. On the water words side, over a hundred words are depicted as waveforms. On the other side, the wavelengths of hydrogen and hydroxyl, components of water, are etched into the plate.
METI International funded my collection and arrangement of water words, as well as my design of hydrogen and hydroxyl lines, providing them free of charge to NASA.
When designing Europa Clipper’s message, we need to consider the importance of water on Earth and why astronomers feel so compelled to seek it beneath the icy crust of Jupiter’s moon Europa. The spacecraft is planned to enter Jupiter orbit in April 2030.
This article is republished from The Conversation, an independent, nonprofit news organization providing facts and analysis to help you understand our complex world.
Written by Douglas Vakoch California Institute of Integral Studies.
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Douglas Vakoch does not work for, consult, own shares in, or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond his academic duties.