Our Celestial Trinkets, and What They Say about Us
published during a waxing crescent moon.

Outbound from Pluto, a postage stamp flies at 32,000 miles per hour. Printed on it are an illustration of an orb—a planet, but generic—and the words “Pluto: Not Yet Explored.” The stamp is a cheeky, defiant message carried on the New Horizons spacecraft, whose second act following a successful reconnaissance of Pluto is the flyby of an object in the Kuiper Belt. After that flyby is complete, scientists will look for another object to explore, and maybe another, and when the spacecraft runs out of fuel, New Horizons will continue flying across the galaxy, unhindered for hundreds of millions of years, if not forever. As such, the words “Pluto: Not Yet Explored” will almost certainly outlast the human race, if not the planet Earth itself.

Since 1959, humankind has sent forth spacecraft whose non-scientific payloads amount to part messages-in-bottles, part emissaries. These spacecraft operate on lifetimes only scarcely imaginable. They might pack power sources able to sustain operations for fifty years, but once their missions conclude, the time capsules within will continue operations, of sorts, for eons, the ultimate extended mission: that of ambassador, that of commemorator. Spacefaring craft on trajectories beyond the limit of the solar system bring messages from Homo sapiens, a species long gone. Spacecraft, meanwhile, that have landed on other worlds will survive as tiny undisturbed monuments to a race of beings that would not be confined to a single planet.

Celestial Trinkets

Photograph of Charles Duke’s family on the lunar surface. Credit: NASA

If ever these objects are discovered by some intelligent alien life, what a warped understanding of humanity these beings will take away. David Clarke, the celebrated British archaeologist, once described his field as “the discipline with the theory and practice for the recovery of unobservable hominid behavior patterns from indirect traces in bad samples.” Our spacecraft and the celestial markers left behind are this description’s apotheosis.

Consider what today rests on the moon. When astronaut, Charles Duke, walked on the lunar surface as part of Apollo 16, he left behind a family photograph of he and his wife and two grinning young boys. Forty-five years later, the Dukes are still married, and their boys have given them nine grandchildren. Few things in life are harder than marriage and parenthood—to say nothing of astronaut selection and training!—and yet Duke did it, all three taken as far as life allows. Regardless of how Duke’s life might have unfolded back home, however, what a message he left for eternity! Humanity will come and go—one day the top of the food chain, the next an asteroid-induced cosmic memory—and yet forever and ever, the Dukes will smile, love planted in their hearts, at the Milky Way above. This is how humans behave.

Celestial Trinkets

Illustrations and annotation of the Pioneer plaques. Credit: NASA

Due west of the Duke family, whose image enters immortality, protected from war, fire, and the ravages of the elements, is a place called Fra Mauro, where landed the mission Apollo 14. It was here that Alan Shepard, the first American in space, stepped from the lander, Antares, and became the only member of the Mercury 7 to also walk on the lunar surface.

Few at NASA knew what secret mischievous activity Shepard had in store.

“Houston,” he told mission control one day from the lunar surface without warning, “you might recognize what I have in my hand is the handle for the contingency sample return; it just so happens to have a genuine six iron on the bottom of it. In my left hand I have a little white pellet that’s familiar to millions of Americans. I’ll drop it down. Unfortunately, the suit is so stiff, I can’t do this with two hands, but I’m going to try a little sand trap shot here.” With that, he became the first human to

With that, he became the first human to play golf on another world, describing one of the balls he struck as going “miles and miles and miles.” (Confirming also the joke that real golfers have two handicaps: one for bragging and one for betting; the ball actually traveled 200 yards or so.) Whether the story survives the test of time—that depends on how far humans go—those golf balls, possessing little practical use, tell the universe that we played games, and thus felt joy and sought a kind of communal, meditative relief.

Years earlier still, when the Soviet Union crashed Luna 2 onto the moon’s surface, it became the first nation to place an object on another celestial body. The “spacecraft”—this term was still new at the time, shiny and exotic, first appearing in quotes in the New York Times—likely vaporized on impact, though it did good science on the way down, and carried within its spherical hull two of what looked like chrome soccer balls. Each constituent pentagon that made up the soccer balls had (and if they survived, has) embossed on it the Soviet coat of arms on one side, and what translates to “USSR January 1959” on the other. The orbs were designed to explode outward on impact, sending Soviet shields in all directions. So it would go, the first artifact of the human being, a non-native, non-invasive species.

Celestial Trinkets

Cover of the Voyager golden record. Credit: JPL

Nine other successful Luna missions were known to carry such “pennants”—proof that the Soviet Union was here. They grew in sophistication—colorful and beautifully engraved, with later pennants featuring a stellar map leading back to the Soviet Union. An alien archaeologist a million years hence could pick up a pennant from Luna-24, look up at Earth in the distance, and make out precisely where the Soviet Union once was as Asia spun into view. There is pride on these tiny shards of metal—This is who we are! This is what we’ve done! Collect our tokens of accomplishment here and come see us on the planet below! It’s all very official but somehow comes across as gleeful rather than zealous.

“This is who we are! This is what we’ve done!”

The Soviet missions to Venus would carry on the tradition, with many featuring maps of the solar system revealing the planet from which they came, and Venera 5 containing not only a map of planets orbiting the sun but a map of Eastern Europe at an approach vector. Looking down from your visiting spaceship, you would know precisely the region that sent this astounding artifact to the world next door. Maybe you would want to visit.

On our other neighbor, affixed to the much more recent rover, Curiosity, is an authentic 1909 penny, Lincoln-side out. It is used as a target to calibrate the Mars robot’s MAHLI camera. In part, this is a nod to the field practice of placing a familiar object in a photograph of a geologic feature so as to establish scale. A plaque on Curiosity featuring color swatches and lines of varying size and thickness is used for calibration as well, and at the bottom of this chart is a cartoon alien called Joe the Martian, first dreamed up by Mars geologist Ken Edgett when he was in the fourth grade. The playfulness! The practicality! Who were these human beings?

Consider Voyagers I and II, both bound for interstellar space, both in possession of “golden records” that Carl Sagan described as bottles launched into the cosmic ocean. The record covers feature illustrations explaining how the records work. It’s an ingenious artifact in and of itself: the speed of the record is explained as it relates to the time period of the fundamental transition of a hydrogen atom (hydrogen being the most abundant element in the universe). The waveform of the record’s video signals is depicted, as is the mechanism of how the scanlines of the video work. Pictured also is a drawing of what the first image on the recording should be, should it be correctly interpreted (a circle).

Celestial Trinkets

New Horizons PI Alan Stern in front of Pluto: Not Yet Explored stamp. Credit: NASA HQ

Were an extraterrestrial race to find Voyager, its best scientists deciphering our code and getting the record to play, they would find the ultimate self-portrait of humanity: the music of Beethoven and Mozart and Chuck Berry; images of food, humans, insects, and animals; whale song and samples of greetings in 55 languages; a selection of mathematics, physics, and anatomy; the structure of DNA; and such wonders of the world as the Great Wall of China and the Taj Mahal.

They would see a playful people with a sentimental streak.

Is all of this an accurate view of humankind? What would some other intelligence think of human beings with only a spacecraft and its contents from which to work? If they were able to make anything at all, they would see a species of engineers, who harnessed the resources of one world—metals, minerals, and fuels—in order to explore another. They would see a playful people with a sentimental streak. They would see a people who did all of this not to destroy, but to learn—and what deep learning they did! There’s little practical application for the understanding of cosmic rays in the interstellar medium, and yet humans did it. Extraterrestrials might look at our species in awe, reasoning that the rockets necessary to loft these spacecraft could have been used for weapons of war, and yet we built rockets instead for scientific inquiry. Human beings, the paragon of sentience! Behold what a primitive species can do when they reject conflict!

Celestial Trinkets

A copy of the Soviet pennant sent on the Luna 2 probe to the moon, at the Kansas Cosmosphere. Credit: Patrick Pelletier

How fortunate we are that the bad sample for alien archeologists was built by scientists. How sorry indeed that we do not live up to the ideal we have put forth for the universe to observe. How sad that we do not even try—that we, indeed, ridicule the very notion of artistry, of science, of expertise and knowledge for its own sake.

Perhaps, though, that is an excessively negative view of humankind born of dark times. We did, after all, produce men and women with the stuff to build these cosmic communiques. Auden’s final poem, through the prism of Voyager, Apollo, and other robots and relics resting forever, takes new meaning:


From Archaeology

one moral, at least, may be drawn,

to wit, that all


our school text-books lie.

What they call History

is nothing to vaunt of,


being made, as it is,

by the criminal in us:

goodness is timeless.

Such goodness can be found on plaques affixed to the Pioneer spacecraft, themselves timeless. Engraved on sheets of gold-anodized aluminum are, among other things, the planets of the solar system—nine in total, with Pluto proud among its celestial brethren. The argument over Pluto’s planetary status can continue until the spark of human civilization flickers and fades to black. Pioneer, though, will last forever. The science of eternity laughs at the science of today. On a long enough timeline, Pluto wins the debate.