The Apollo 11 spacecraft on the moon bears a plaque stating, We Came in Peace for All Mankind. So far, four spacecraft have left our solar system, and each has carried a greeting from humanity to any extraterrestrials they might encounter in their endless trek through our vast and beautiful Milky Way Galaxy, shown in my painting above. The two Pioneer ships had their iconic plaques complete with drawings of the human body, and the two Voyagers had their legendary Golden Records. I worked with astronomers Carl Sagan and Frank Drake on that last project, where we created a message describing our world in music, sound, and images crafted in a way that ETs might understand.
But NASA’s latest interstellar mission says only Made in USA. The New Horizons spacecraft, launched in 2006, continues to exit the solar system. In January, it will fly past a small icy world dubbed Ultima Thule. But New Horizons will then wander forever among the stars without a message for anyone.
It could have been different. The One Earth Message, a private initiative I started in 2012, aimed to create a 150 MB digital message intended for upload and permanent storage in the spacecraft’s onboard computer. Unlike the previous messages, made by a very small group of Americans, the OEM would have been crowdsourced, created by many people around the planet. But OEM failed to gain NASA’s support and was never implemented. Instead, the only nonfunctional cargo is a handful of context-free symbolic items that would be, to put it mildly, a challenge for any ET to understand.
Even more disappointing: All of the objects are from the United States. There is no hint there is any other culture on Earth. There are American stamps and American coins, two American flags, and a piece of another American spacecraft. All the examples of writing are in English. Unlike Voyager’s Golden Record project, these tokens are not from the entire human species. In a strange premonition of Trumpism, this spacecraft was launched representing only one nation. Nothing could be further from Sagan’s belief that spacecraft going to the stars should speak for all of humanity.
Here are the objects the spacecraft contains, how they fall short, and how ETs might interpret them (or try to).
Two CD-ROMs. One contains photos of the mission team, the other the names of space fans who sent in their names. But without some guide to the software, these will forever be unreadable. Unlike the analog format of the Voyager Records, the digital formats are impossible to decode, though ETs might conclude a laser was involved. But since the files themselves are based on arbitrary principles and without instructions (not provided), ETs can never see them. They won’t even know they are pictures. And without knowing what ASCII files are, there is no way the names could be even displayed. How frustrating for our distant alien friends 1 million years from now!
A piece of SpaceShipOne. SpaceShipOne was part of an unsuccessful private initiative in the mid-2000s to launch people to low Earth orbit. There is no particular connection to Pluto or planetary science. It’s just a nod from one mission to another. To ETs, it’s merely a simple piece of hardware, meaning unknown.
Two U.S. postage stamps and quarters. Neither the mission nor the Guinness Book in which they appear give the names of the artists for the stamps or coins, but kudos to them. Their work is going to the stars! But will any of the images on the stamps remain visible after many millennia? Cosmic rays will take their toll on most chemical dyes. Perhaps ETs can reconstruct the images from remaining traces. If so, the sunlit planets may be recognized, since ETs will certainly have seen other sunlit worlds.
They may be able to glean a bit of information from these objects. The characters on the stamp are the same as those used elsewhere, possibly a confirmation that they are language. On the coins, some words are repeated. Will the different fonts make compared identification more difficult? ETs may argue over whether the repeated word Pluto is our world’s name or this spacecraft’s destination. The edges of the stamps are scalloped, a result of detachable stamps being sold in sheets. Will ETs compare it to the ridged edges of the two coins? Will ETs guess that both are functional?
The two coins represent the states where the spacecraft was built and launched. Metal disks make durable artifacts, though ETs might wonder why they are so thick. Perhaps this is a clue to the coins having some other function. The coins are identical on one side and different on the other. Each shows George Washington, the only image of a human being aboard. Will he be recognized as a living being? At least the coin is in bas-relief, handy for blind ETs.
The coin from Maryland, home to the Applied Physics Lab that built and currently operates the spacecraft, shows the Old State House flying two flags.* Will this be recognized as a building? Is architecture universal? Will the flags provide a clue to the function of the real flag aboard? There are two sprigs of white oak—Maryland’s state tree—perhaps identifiable as a plant by ETs.
The Florida coin shows a 16th-century Spanish galleon, NASA’s Space Shuttle, and a strip of land with Sabal palm trees. If alien life-forms can recognize any of these, they’ll get a little idea of what else humans have made and where we live.
ETs may struggle to understand the purpose of the ridged edge of the coins. At first they might be mistaken for gear teeth, a logical explanation. As I discovered in a boring 10th-grade class, lay two quarters side by side and they make an amusing two-gear train. (Try it!) The spacecraft contains other gears aboard, perhaps even similar in size. Maybe the coins will look like spare gears? This will be a rich blind alley for ET interpreters. Coins were originally ridged to deter thieves from paring the silver edges of coins. You can also tell them apart in your pocket. ETs will only guess this if they have faced an identical problem. Maybe they have. Money, theft, and pockets may be universal. Whatever the result, one thing is undeniable: On Voyager we sent Mozart and Chuck Berry. On New Horizons we sent small change.
A nylon American flag. As an example of a fundamental human invention, fabric is not a bad choice. Cloth made it easier for our ancestors to protect skin. Clothing and fashion were not far behind, as well as diapers, carpets, sails, and the ever-useful rag. Eventually cloth hybrids would even protect spacecraft from heat and cold. New Horizons itself is wrapped in high-tech foil blankets. And fans of Douglas Adams’ classic Hitchhiker’s Guide to the Galaxy will recall that the vital equipment for interstellar travelers is a towel!
Perhaps the Maryland coin will provide the clue to the function of this flag. But there is nothing to explain the symbols, even if they remain visible after many millennia in space. The 13 stripes are a prime number, perhaps a misleading nonclue. And each five-pointed shape is unlikely to be recognized as a symbolic star, though this pentagram does have some interesting —and irrelevant—geometrical properties.
There is nothing special mathematically about 50. The array of 50 identical stars is unlikely to be language—and the stars do not appear on either stamp or coin. ETs are as unlikely to guess that there are 50 States as they are to guess that 50 is the jersey number of Boston Red Sox great Mookie Betts.
All ETs can conclude is it must have meant something to us, something important enough for it to appear twice—once on fabric and once as a decal on the spacecraft.
That brings us to the most important thing contained on the spacecraft: the ashes of Clyde Tombaugh.
Tombaugh discovered Pluto in 1930 when he was 24. He lived to see the Voyager spacecraft fly past Neptune in 1989. In a noble gesture, the mission carries some of his ashes aboard and flew them past his planet. No astronomer—no Pharaoh—ever had as spectacular a tomb.
Of course, ETs won’t know what these ashes are until they analyze any microfragments of bones and teeth that remain after cremation. How much might ETs learn, or even create, from that? In my own lifetime, I have seen the biologically impossible become real—for example, when the DNA of the extinct quagga was recovered from a desiccated skin fragment in 1984, something flat-out impossible a decade earlier.* Now there are serious conversations about using cloning to bring back extinct species. How much of Tombaugh’s DNA is recoverable? If ETs can’t even figure out an image file, cloning might seem like a stretch—but unlike JPGs, biochemistry follows laws that are universal. Amino acids and other organic molecules form naturally everywhere. But without knowing what they are cloning, ETs might well expect the ashes to come from the white oak or Sabal palm trees on the coins.
Washington’s head is the only clue to what we looked like.
If ETs could clone Tombaugh, he might be the loneliest human ever, unless they make duplicates. Perhaps some version of the great astronomer will walk again one day. He’ll wonder about these few tokens of his home planet.
The odds against it are millions to one. But the odds of New Horizons being found are at least that long. And it still might happen someday. Without any real message provided for ETs, the items described here are the only message ET will get. These few tantalizing fragments may be all that will speak for Earth. I wish we had told them more.
Correction, Dec. 27, 2018: This post originally misidentified the Applied Physics Lab as the Advanced Physics Lab. This post also originally misidentified the extinct quagga as a bird. It was a member of the horse family.