5 Apocalyptic Messages We’ve Sent to Our Distant Descendants

5 Hunger Stones Warn That Famine Approaches

In the old days, simple changes in the year’s weather patterns defined how you would live. If drought kicked in, crops would fail, and you would go hungry. People would die. If you received a healthy level of rain, crops would thrive, and now, well, you’d probably still go hungry, and people would still die, but you wouldn’t be as hungry, and not as many would die, so it would be a time for celebration.

In Central Europe, many communities had a way of marking droughts. They would carve a message into a rock in a river. During a good year, or even a good century, no one would see the rock. Then, sometime in the distant future, the river would shrivel, and the stone would appear. Perhaps (reasoned those who carved the stone) people all the way in the future wouldn’t even know the danger dryness poses, until they see the hunger stone. 

The oldest stones go back almost a thousand years. A newer one in a Czech town bears the following message: Wenn du mich siehst, dann weine. Translated, it says, “If you see me, then weep.” These stones weren’t just about despair, however. A later message, added during a 1938 drought, reads, “Girl, don’t weep and moan, if it’s dry, water the field.” Another stone tells people that droughts needn’t last forever. “When this stone goes under,” it says, “life will become more colorful again.”

We’ve seen a bunch of these stones become more visible recently, thanks to a major drought in Europe — one that’s not just the worst in a century but maybe the worst in 500 years. If it’s any consolation, we perhaps don’t need to panic in quite the same way someone did on seeing a hunger stone in 1473. Thanks to better trade, preservation and agriculture, Germans today aren’t starving to death like people back then did, even at lower water levels. Plus, thanks to wider entertainment options, we’re also much better equipped to ignore incoming disasters, if we so choose. 

4 A Song in a Germ

But maybe drought won’t wipe us out. Maybe someone will finally solve world hunger, by finally setting off nukes and killing the hungry and the full alike. No humans will survive. But you know who might? Deinococcus radiodurans.

Deinococcus radiodurans (which we’ll call “Conan the Bacterium” going forward, for simplicity) is an especially hardy kind of bacteria. It shrugs off freezing temperatures and UV light. Harsh chemicals and acids similarly do nothing to it. It doesn’t dry out. And when powerful radiation hits, not only does Conan survive, it also doesn’t seem to mutate. Long after all our records are wiped, this bacteria’s genome will remain intact. 

As a result, scientists have carried out serious experiments into storing data by manipulating nucleotides in Conan specimens. As generations pass, even asexual organisms’ genes change due to mutations, but Conan has a way of repairing any that kick in. This defense would even cause it to repair messages that we insert, but we invented a marker on the bits we edit to prevent this. 

One MIT poet ciphered his poetry into DNA and stuck it into Conan. Other scientists, meanwhile, chose verses of a different kind: They chose the lyrics to “It’s a Small World.” Because if these messages do outlive our species, we want whoever reads them to suffer as we did. 

3 Beware of Radiation, People Who Don’t Speak Language

While a sufficiently powerful dose of radiation might wipe us all out, we also have to consider the effects of radiation that are not apocalyptically dangerous, just very dangerous. Such as, say, heavy nuclear waste, stuff like neptunium and americium, some of which will remain radioactive for hundreds of thousands of years. We store such waste in deep caverns under New Mexico. We can seal those caverns up tightly when we’ve filled them. But that might not stop a sufficiently enterprising future archaeologist from spelunking and bringing the stuff home to serve as soup. 

We need to label the site. Perhaps by burying many copies of this design in the dirt, so whoever digs through that ground is bound to run into them:

However, what if by the time people reach these markers, the world has forgotten what those radiation symbols mean? And what if they don’t read English — well, that’s why other markers use other languages, but what if the hypothetical speaker doesn’t speak any language we know now? If they don’t, that’s what the scared faces are for. But facial expressions, while slightly more universal, are still open to interpretation. Maybe those people are excited, or horny. Even in the three decades since this marker was proposed, those faces have attained an unwanted meaning (it’s called a “pointing soyjak,” and if you’ve never encountered that meme, you’re lucky). 

If we use pictograms, they must transcend language, as in this next proposed design. Knowledge of radiation symbols, distances and words would help you understand it. But even if you know none of that, you should still be able to see someone drilling and releasing something that kills them, right?

Oral tradition, meanwhile, has the potential to outlive any written message. In 1972, Hungarian linguist Thomas Sebeok suggested creating a system whereby a small academic elite would know the truth about the nuclear site and would pass the knowledge down through an intellectual oligarchy. Restricting this knowledge would seem to work against the purpose of perpetuating it, but marking the information as precious would encourage the Atomic Priesthood to never forget it. These priests would be in charge of telling the common people to avoid the site, without explaining just why. 

In 1984, two philosophers, Françoise Bastide and Paolo Fabbri, proposed what they called the Ray Cat solution. We could genetically engineer cats to change color when they encounter radiation. They would act as living Geiger counters, and this species would outlast any mechanical Geiger counter we now build. Then, we’d just have to cultivate a tradition by which everyone knows that when a cat changes color, you must flee this dangerous area. 

Like most scientific thought experiments involving cats, it’s possible this was meant as more of an illustration than a practical suggestion, to show how to combine tangible changes with “intangible socio-cultural components.” It’s still been the most popular suggestion among nonscientists. This song, from 2014, is an example of one way to keep the fear of color-changing cats alive:

Slightly less weird, and also still not implemented, was the idea to reshape the landscape here to look inherently hostile. Just blowing up a bunch of boulders with dynamite on the surface would give the impression that something weird happened here. Or we could lay down one enormous, terrifying slab of pure black stone. Spikes, concluded one report, are universally feared. We could build giant spikes coming out of the ground, or just moderately sized spikes in multiple directions, to form a Landscape of Thorns.

The fear, though, is that our distant descendants might dismiss any warning as irrational superstition rather than a genuine hazard. Think of how often our own archeologists stumble on some 5,000-year-old coffin with warnings to leave our hands off, and immediately reach for their crowbars. We’re a curious species. This may lead us to fry to death in radioactive goo, but it’s also why we’ve accomplished so much. Hey, maybe we can create some oral tradition about the dangers of curiosity. Maybe something involving a cat. 

2 Japan’s Anti-Tsunami Warning

“A home built high is children’s relief,” reads the following stone tablet. “Remember the calamity of the great tsunamis. Do not build any homes below this point.”

This stone was laid down in 1933 in the village of Aneyoshi in Japan. The generations who saw it did follow its advice. The 2011 tsunami saw 100-foot waves hit that prefecture, and some 20,000 people died in total. But in Aneyoshi, people only lived in homes above the stone, and they all survived. Aneyoshi survived a tsunami in 1960 as well, while tsunamis had destroyed the village multiple times before the stone was erected.

Other stones like this are older. Some were carved thousands of years ago. “If an earthquake comes, beware of tsunamis,” says one, simply. “Always be prepared for unexpected tsunamis,” reads another. “Choose life over your possessions and valuables.”

We have other ways of passing this knowledge down now. But following the 2011 tsunami, the Japanese guild of stone masons revived the practice, creating even more warning stones and setting them down. So, good news. Masons really do take it on themselves to control the world. 

1 A Satellite That Will Crash in 8 Million Years

Orbiting the Earth, at an altitude of 3,600 miles, is a satellite called LAGEOS-1. It contains no power source, no communication equipment and no moving parts. It’s just a big ball covered in reflectors, made of glass and germanium. It’s up there so we can shine lasers on it, measure how long they take to come back and calculate exactly where we are. 

“Hold on,” you might say. “I already know where I am. I’m right here! And if I’m in one of the Satellite Laser Ranging sites that use LAGEOS, I definitely know where I am.” True, but by bouncing lasers off LAGEOS, we can track our position even when the ground we’re on moves, with respect to some fixed position (other Earth landmarks are also moving). We measure tectonic plate movements this way, measure if each day gets a few nanoseconds shorter and check out if the planet’s axis suddenly decides to go rogue on us. 

LAGEOS is high enough that it avoids most of the particles that hit lower satellites, slowing them down. Even so, it won’t orbit stably forever. NASA predicts that it will fall back down to the planet’s surface in around 8 million years. We don’t know just who’ll be around to see it land, but for whoever does, we stuck a plaque on there, designed by Carl Sagan. It looks like this:

That bottom image shows LAGEOS falling. Those are the continents, as we predict they’ll look in 8 million years — hopefully, this plaque’s unnamed recipient will recognize those. The middle image shows LAGEOS going up, and shows the continents as they exist now. The top image? Those are the continents from 270 million years ago. 

We date the images using binary, and the legend at the top of the plaque attempts to teach binary notation, as well as depicting the passage of one year. We designate our time as year 0. Eight million years in the future is (about ) 2 to the 23rd power, as shown in binary by that 1 followed by all those zeros. 270 million years ago is 2 to the 28th power. Eight million years might sound like an impossible length of time, but on a planetary scale? It’s not really that long at all. The Earth will still be here. 

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