How to build something that lasts 10,000 years
When I visited Japan recently, I witnessed the 66th cycle of a ritual that began more than 13 centuries ago. I watched as Crown Princess Masako led a procession of Shinto priests carrying treasures from the old temple to the new. In Ise, they have been rebuilding the grand Jingu shrine with wood and thatch every 20 years since at least the 7th Century. As part of Shinto ritual, this not only keeps the structures intact even when made out of relatively ephemeral materials, but it allows the master temple builder to train the next generation.
最近，我去了一次日本，有幸见证了一场仪式。这种仪式1300年前就在日本出现了，如今是第66次。庆典中，皇太子妃雅子带领着一队神道教的祭司，将旧神宫里的物件搬迁到新建好的神宫之中。公元7世纪以来，伊势神宫本殿（Ise Grand Shrine）每隔20年就会依原型重建。迁宫是神道教诸多仪式之一。建筑神宫的建材很容易损坏，重建神宫，既能够保存其特色建筑的完整性，又有利于让下一代工匠学习营造技术。
Japan is also home to most of the oldest companies in the world, and has a singular affection for maintenance that allows it to sustain structures and rituals for millennia. But many other cultures have created long lasting artefacts and buildings, and each one can teach us something.
Over the last two decades, I have been working at The Long Now Foundation to build a monument-scale “10,000 Year Clock” as an icon to long-term thinking, with computer scientist Danny Hillis and a team of engineers. The idea is to create a provocation large enough in both scale and time that, when confronted by it, we have to engage our long-term future. One could imagine that if given only five years to solve an issue like climate change, it is very difficult to even know where to begin because the time scale is unreasonable. But if you reset the scale to 500 years, even the impossible can start to seem tractable.
在过去的20年里，我和恒今基金会（Long Now Foundation）合作，同计算机科学家希利斯（Danny Hillis）以及一个工程师团队一起，要建造出一座具有纪念碑意义规模惊人的“万年钟”，以警示人们注重长远考虑。我们的理念是铸造一座规模巨大、时间跨度很长的钟，当面对它时，会激起人们为长远未来考虑的想法。我们可以想象，要是在5年之内解决气候变化这样的问题，是十分困难的，因为时间跨度太小。但如果把时间跨度调整到500年，那么即使是最不可能的事情，也开始变得容易处理。
Building a 10,000-year machine required diving into both history and the present to see how artefacts have lasted. While we can slow the workings of the clock itself down so that it only ticks as many times in 10,000 years as a watch does in a person’s lifetime, what about the materials and location? Over the last 20 years I have studied how other structures and systems have lasted over time, and visited as many of them as I can. Some sites have been conserved by simply being lost or buried, some have survived in plain sight by their sheer mass, others have had much more subtle strategies.
Few human-made objects or organisations last more than a handful of centuries, much less millennia. Stories, myths, religions, a handful of institutions, as well as some structures and artefacts have lasted this long. Most of these were not built with the intention of extreme longevity, but are accidents of history. More recent efforts such as nuclear waste sites, genealogic repositories and seed vaults, are being designed explicitly to last for thousands – or even hundreds of thousands – of years. There are a series of lessons we can learn from the past and present, ranging from material science and engineering, to the ideological. I will cover several of these as well as discuss how they have influenced our work on the 10,000 Year Clock.
Lost & found
Some of the most unique and meaningful objects from history have survived not by intention, but by being lost and then found at an opportune moment. The Dead Sea Scrolls, the Rosetta Stone, and the Antikythera Device never would have made it to modern times without first being lost. The Antikythera Device has been of particular interest to me because it was also a planetary clock of sorts – centuries ahead of its time. It was discovered as chunks of oxidised gearing in a 2,000 year-old shipwreck near Antikythera, Greece.
历史上一些最独特、最有意义的文物，之所以能够保存下来，并不是人们刻意为之。相反地，人们曾经将其遗失了，在偶然的机缘之下又找了回来。比如：死海古卷（Dead Sea Scrolls）、罗塞塔石碑（Rosetta Stone）和安提基奇拉机械装置（Antikythera Device）等，如果没有开始的遗失，它是不可能保存到现在的。安提基奇拉机械装置对我有着特别的意义，因为它也是一个行星钟，而且它十分超前，领先那个时代几个世纪。人们在希腊的安提基奇拉附近发现了一艘2000年前的沉船，船上大量已经氧化的传动装置，就是后来的安提基齐拉器械装置。
No similar device has ever been found from that era. Its workmanship and understanding of gearing and celestial events are remarkable in that many of the ideas and mechanical principles would not be seen again until Europe emerged from the dark ages 1,300 years later. In addition, it would have taken many iterations to build such a device, so it is a further mystery that we don’t have any other examples of devices like this. Clearly the only reason this one survived was because it was lost. But even after being found, it languished for decades in storage before X-ray studies revealed its true complexity and purpose as a working astronomical model.
The other lesson learned for our 10,000 Year Clock project is that mechanical objects are much better at self-documentation for a future archaeologist than electronic ones. You could imagine if they had found a modern electronic device at the bottom of the Mediterranean after 2,000 years, it would be almost impossible to determine the intentions of its silicon circuits. This is one of the main reasons that we are building a large mechanical device. Even if only parts of it survive the entire 10,000 years, it is likely that people could determine its purpose and even repair it if needed.
Cities are defined by churn. Cities themselves can often thrive for more than 1,000 years, but the contents within them turn over with each passing decade. For every urban artefact that has lasted over a millennium, there are countless more that were destroyed by war, civic changes, or accidents. Remote places generally have created much more opportunity for long-term survival. Spectacular sites like Petra and Machu Picchu were most certainly preserved due to their distance from modern cities.
Remoteness can also lend a more mythic presence to a site. Several winters ago I travelled to the Global Seed Vault located in Svalbard, the most northern permanently inhabited place on Earth at 78 degrees latitude. The vault was designed to last for over 1,000 years as a backup repository of the world’s crop seeds. However, in building it, the designers failed to realise how much it would capture the imagination of the world. It was not designed for visitation, and they found themselves telling dignitaries who travelled there from around the world that they could only see the outside of it. In the case of our trip we had timed it to one of only two times a year they open the vault to deposit seeds. As I signed the guest book I saw the names of previous delegations that included people like Jimmy Carter and Ban Ki-moon, I realised that the remoteness of the site made it only more interesting to the outside world.
Remote sites also require intention and time to reach rather than being a “drive by” location. Travelling to a specific destination means that people who visit it get transition time as they voyage there, and most importantly on their way back. For the 10,000 Year Clock site we have selected a site in far West Texas that is many hours from airports and that will require a day of hiking to visit. Since the clock project is meant to change the way people think about time, the remote site gives both anticipation and time to process the visit, making the isolation as crucial to the mythic qualities as it is to preservation.
Many of the best preserved artefacts probably spent most of their time underground. The subterranean environment protects them from sunlight and generally keeps a very stable temperature. The rise and fall of temperature accelerates oxidation and aging. In fact, when manufacturers do rapid aging tests for materials, it is done largely through cycling temperatures up and down (and chemical effects, which we will get to next).
The ornate tombs of Luxor, Egypt, cave paintings such as Lascaux in the Les Eyzies valley of the Dordogne in southwestern France, and even delicate artefacts such as the Dead Sea Scrolls were all preserved underground for thousands of years. It is no wonder that modern efforts of preservation such as the Global Seed Vault, nuclear waste repositories and archives are all built beneath the surface.
There is, however, one serious drawback to trying to preserve things underground – water. I have visited nuclear waste sites in the US and Europe, the Global Seed Vault, and the Mormon Genealogical Archive – and in every case they are fighting a losing battle to keep water out. Over centuries and millennia, water will always find a way in. The only successful mitigations of water I have seen are when it is redirected rather than blocked. The ancient rice paddies of Asia are a testament to the effectiveness of carefully directing water over thousands of years.
Building the 10,000 Year Clock underground is important not only for preservation, but for timekeeping as well. Temperature change causes metals to expand and contract, requiring clever and imperfect schemes to keep devices like pendulums at the same length, and therefore keep regular time. The less temperature change a mechanical clock experiences, , the more accurate it will be. However, after witnessing the struggles with water at nearly every underground site I have visited, we had to think very carefully about how we tackle it. Our underground site is built at the top of a mountain in order to minimise the area of drainage that can collect water, but we still assume that water will get in. To address this eventuality, we angled every underground surface away from the clock and made sure that water would not be trapped anywhere and could escape at the bottom of the site. If we can’t stop the water, we can choose where to direct it.
One of the first material scientists I spoke to about making things that last for thousands of years offered a compelling insight: “Everything is burning, just at different rates.” What he means is that what we perceive as aging is actually oxidisation, like rusting. When we imagine materials that may last for thousands of years, most people think of stone or precious metals like gold – because they don't oxidise readily. But even bodies can be preserved for millennia if stored in the right chemical environment, as the mummies of Egypt demonstrate. Not long ago a perfectly preserved leather shoe was found in Armenia dating from over 5,500 years ago. The longevity of a material is often less about the object itself, but much more about the environment it is in. In the case of the leather shoe, it was buried in a cave and sealed in by sheep dung, thereby creating the perfect anaerobic, stable temperature environment.
But to build objects and machines that people interact with over thousands of years, we have limited ability to control that environment. People breathe the same oxygen that degrades materials, and they bring in dust on their clothes, and oil on their skin. To build a working machine that people can visit for 10,000 years, the materials themselves must be long-lasting.
Probably the best example of this are the bearings that we are using for the clock. All the rotating parts in the clock require some sort of bearing surface in order to smoothly roll with minimal friction. However, there are several problems with traditional bearings, which are usually made of a row of hard steel balls between specially-ground tracks called races. Steel or even stainless steel bearings will simply weld together if left for long periods of time, and they also undergo another process called galvanic corrosion if they are separating two metals with different electrical potential. If you have ever seen the way a penny corrodes when left on another metal surface, this is galvanic corrosion. In addition to these issues, normal bearings require lubrication – but that means regular maintenance – and can attract dirt and grit.
Over 20 years ago when I started this project in researching bearings, we found the perfect solution: an all ceramic bearing created for use in satellites and spacecraft. Made of near-diamond hard industrial ceramics, these bearings were designed to operate without lubrication in the vacuum of space indefinitely. There was only one problem: when I first heard of these bearings, they cost tens of thousands of dollars and were only used in aerospace. Over the course of our project, however, they have become more common and are now used in roller blades and fidget spinners and can cost as little as $10.
One of the more surprising strategies for longevity is actually to sacrifice some part of the object itself. We see this in nature where a lizard’s tail can break off when attacked, allowing the lizard to escape alive.
Some sites have this same quality, like the tombs in the Egyptian Valley of Kings, where the best preserved examples of carvings and colour look like they could have been finished just yesterday. When the grave robbers spent all their time stealing the gold objects out of the tombs, they thought they had extracted all the value, but they left the wall art untouched, which was rare when compared to other sites.
有的遗址也有类似的情况。比如埃及帝王谷（Egyptian Valley of Kings）的墓葬中，保存最为完好的雕刻和色彩画仿佛昨天才完成。盗墓者往往把时间花费在将金器运出墓葬上，并感觉已经将财物搜刮殆尽，把有价值的都挖出来了。然而，墓穴里的墙面艺术仍然完好无损。这与其它遗址相比是罕见的。
The jewel-encrusted walls of the Taj Mahal may also have helped preserve the structure by assuming all the value had been taken out with the gems. This poses an interesting question for the site we are creating for the clock. Should we have a relatively easy-to-plunder valuable layer that will not harm the clock if it were to be stolen?
Value and ideology
The final and greatest danger to building anything that lasts is human beings themselves. In recent years we have witnessed some of the world’s oldest sites destroyed because their values or ideology were seen as in conflict. One of the more heart-breaking of these was the Taliban’s destruction of the massive Buddhas of Bamiyan in Afghanistan. It is hard to imagine a more innocuous religious symbol than a Buddha, but it was threatening enough to the Taliban to spend weeks blasting these amazing artefacts out of the cliffs.
建造万古长存的东西，最大的威胁是人类自己。近年来，仅是因为价值观或意识形态的冲突，就有人摧毁了世界上最古老的遗迹。其中最让人心碎的是塔利班摧毁阿富汗的巴米扬大佛（Buddhas of Bamiyan）。再也没有比佛像更加无害的宗教象征了，但它却成了塔利班的威胁，让他们不惜花费数周将悬崖边令人惊叹的文物炸毁。
How do we make something of value and cultural significance that will not at some point be stolen or destroyed? This is the true question when we ask how to build something like the 10,000 Year Clock. It is not the engineering of the materials and its workings, but the civilisation around it, which we hope to shape as one that cares for both the present and the future. We hope that by building such things, they challenge us not just technically, but ethically as well. We hope that they challenge us to become better ancestors.