Cosmos 11: The Persistence of Memory

by Shane L. Larson

One of my all time favorite books is the 1952 novel “City” by Clifford D. Simak. It is a yarn spun of a distant future where humans have utterly vanished from the planet, and the Earth is inhabited by an intelligent society descended from our domesticated canine friends.  The dogs regale their young pups with tales of the websters (humans) who once inhabited the world.  After the telling of the tales, the pups are always full of questions: “What is Man? What is a city? What is a war?”  As their elders calmly tell them, “There is no positive answer to any of these questions.”

It is a curious thought, to look at our civilization, and ask what some future generation might ask of us if they had nothing but our cities to look at.  It is a question we often ask ourselves when encountering the constructions of civilizations that have utterly vanished from the annals of history.  Staring at the crumbling remains of ancient buildings, massive temples and pyramids, and monolithic stones, we ask ourselves questions: “Why are these here? What was this for? Who were these people?”

Imagining a distant future without us has become a cottage industry, with striking images by excellent, modern artists, imagined against the backdrop of our greatest cities, such as Chicago (L) or New York (R).

As scientists, when we look at the crumbling remains of lost civilizations, we try to let our minds imagine how it happened.  When I stare into the ruins of a society long since vanished from the Earth, such as the Anasazi of the American Southwest, the Tiwanaku of western Bolivia, or even the ancient Romans, I often wonder what happened near the end?  Did they know their civilization was crumbling, that it would soon be subsumed by the slow and steady march of time?  What did the people think and do as their society was collapsing around them?

(L) The Cliff Palace at Mesa Verde, one example of an abandoned Anasazi city [National Park Service image] (R) The Kalasasaya and lower temples at Tiwanaku. At equinoxes, the sun shines into the Ponce Monolith, aligned in the main door. [Image from Wikimedia Commons]

A typical household bookshelf (this is one of mine) contains a wide variety of books — the collected knowledge, wisdom, and imagining of our civilization, gathered and preserved on paper and capable of surviving into the far future.

But today, unlike 2000 years ago, books and paper and writing abound. In addition to those who diligently secure the knowledge of the human species in scholarly works, there are tremendous amounts of other information being captured by a species that has become enamoured with the written word.  Bookstores abound, and books are produced and sold in massive numbers. Journalling and daily writing are a common and well regarded activity.  People collect, hoard, and use notebooks and fountain pens. Families, libraries, and city councils make and bury time-capsules full of books, newspapers, messages, and artifacts for future generations. I would love to slip into hibernation, and emerge several centuries in the future, to see what survives, and what our descendants think of us after sifting through the surviving scraps. 

A family time capsule my wife and I made in 2000. We picked the 2017 opening date, guessing that any potential children we might have would be in elementary school, and interested in artifacts of the past. Our daughter will be 10 years old when we open this time capsule. The suspense is killing her!  🙂

Imagining how to store information, so our memory persists and is understandable in the future brings three immediate questions to mind: What would we want the future to know about us? What will the future think about us? And how do we get a message (that can be understood) from us to them?

It is a fascinating mental puzzle to me, to try and imagine how best to speak to someone far removed from you in time, if not also in space and culture. Consider this blog.  The post you are reading lives now, in this moment.  Will WordPress and web-browsers and Unicode-8 exist 400 years from now? Probably not. All this will be lost, faded back into the ethereal fabric of the Cosmos.  For the moment, these words are organized into well-ordered bits of data, stored and represented as a few fleeting photons of light that leap from the surface of your tablet to the retina of your eye, where they are transformed into electrical impulses deep in the furrows and cores of your brain. But eventually it will be gone; the memory circuits will be loose silicon atoms in a landfill, perhaps. When I’m 107, I may remember writing this, but when I return to star-stuff, those memories will become unorganized electrical and thermal energy once again, lost forever. Maybe, on a forgotten and dusty shelf, someone will find my hardback copy of Carl Sagan’s Cosmos, the pages somewhat yellowed with age,and obviously well-thumbed, but still readable. They will scan the words, and wonder what it was like to live today, in the age where we were first exploring the Cosmos beyond Earth. But this blog, this personal exploration of Carl Sagan’s Cosmos, will be lost forever.

Do you think the loss of information in today’s age is unlikely?  Try finding something on Geocities — it is estimated that 38 million webpages vanished when it shut down in 2009. Where are the 97 lost episodes of Dr. Who? Information can and does disappear, even in our digital age.  How often do you back up your hard drive? Do you have a copy of every email you’ve sent and received (Stephen Wolfram has his)?  Can you still read the report on life in Rhodesia (now Zimbabwe) you wrote in high school using WordStar? 

The lack of WordStar, the computer it can run on, and a floppy disk drive that can read a 5-1/4” floppy disk means all that you wrote in that report is virtually gone, lost forever.  Technology creates the ability to collect, store, and distribute information; but when the technology becomes obsolete the information becomes endangered.  I’m pretty sure in our family time capsule, there is a VHS tape.  I haven’t owned a VHS player since around 2006, a scant 6 years after I closed up the time capsule!  How am I going to play that tape back???

But the truth is, no matter how carefully we preserve our technology, and strive to make it readable by some distant future generation, it will all be lost eventually.  Because someday, all stars die.  When they do, they destroy the planets around them, and all record of the life and civilizations that may have existed there.  Someday, around 5 billion years in our future, the last day of the Earth will dawn.  The Sun, having exhausted its supply of hydrogen deep in its core, will be on its way to the grave. It will have swollen to enormous size, swelling until it swallows the entire inner solar system during its “red giant phase.”  When that happens, the Earth will be no more.  It has happened to billions of stars before the Sun, and it will happen to us.  When those stars that came before the Sun died, did the galaxy lose some impossibly ancient civilizations?  Does there perhaps exist some persistent memory of them, drifting among the stars?  And if there is, can we possibly hope to understand how those memories are encoded?

I often daydream about a distant future, thousands if not hundreds of thousands of years in the future, where our distant descendants sail the stars. Still not far from us in evolutionary terms, our imagined future descendants will be far separated from us in time, farther than we are from our ancestors who walked the Nile Delta or the Indus River Valley a few thousand years ago. It is improbable, but not impossible, that they may stumble across a ancient hulk drifting among the stars — a device of intelligent design, cast out among the stars by some ancient, long lost civilization.

Taking it amidships, they will quarantine it.  Like us, our descendants will be good at figuring things out — science and engineering are tools that will have allowed them to overcome many challenges, and led them to the stars.  The intriguing device will be scanned, examined, and prodded from afar. Once they are convinced it is safe, they’ll approach it up close, touch its surface, and see how it is constructed. It is only then they will discover a great wonder — bolted to the side, obviously meant for intelligent eyes, is a message. It is not written in any language that they will recognize, but it is clear it is meant to be decoded — a message from the builders.

What will a message found drifting on a lost hulk in space look like? If we stumble on a message, will we be able to decode it?

Science and engineering teams will be brought in, together with linguists, technologists, and mathematicians. They will uncover a code, a simple cipher built around fundamental numbers related to hydrogen, the most common substance in the Cosmos. Following the simple, encoded instructions, they will find sounds and images, and a great mystery. The languages are foreign to their ears, the messages meaningless; but there is music — stunning music; and images, probably of the builders and their far-away world, cloudy and water shrouded.  But the builders are us.  The device is one that you and I are intimately familiar with. We call it Voyager 1, and the message is known as the Voyager Interstellar Record.  But to our distant star-faring progeny, it will be a long forgotten artifact, unknown in the fragmented historical records they have from their past.

It is not impossible that our descendants will have forgotten us, and possibly forgotten the world they even came from.  Consider our own distant past. Some of the oldest known artifacts from our ancestors are pieces of jewelry, made from mollusk shells between 90,000 and 100,000 years ago. We know nothing about the people who made those artifacts, only that they were deliberately made; all other knowledge of them is gone, lost forever.

Someday the knowledge of us could similarly be lost forever, but some small and incomplete memory of us will persist.  Buffetted by the quiet tradewinds of the galaxy, the two Pioneer and two Voyager spacecraft will spend the next billion years sailing the interstellar voids, far outliving their creators, bearing only the merest scrap of memory about who and what we are.

As of this moment, the Pioneer and Voyager spacecraft are the only artifacts of our civilization, the only memory of us, that will definitely persist beyond the death of the Sun.

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This post is part of an ongoing series, celebrating the forthcoming science series, Cosmos: A Spacetime Odyssey by revisiting the themes of Carl Sagan’s classic series, Cosmos: A Personal Voyage.  The introductory post of the series, with links to all other posts may be found here:  http://wp.me/p19G0g-dE