Would it be possible to detect an industrial civilization in geological record?

https://arxiv.org/abs/1804.03748

by notional • 6 years ago

156 178 6 years ago

arxiv.org

notional• 6 years ago

Article by the authors of this paper,

https://www.theatlantic.com/science/archive/2018/04/are-we-e...

hn_throwaway_99• 6 years ago

I admit I did not read the entire publication, but, at least at face value, this seems somewhat absurd to me. Within the past couple hundred years humans have built massive structures in cities that should last for many millions (hundreds of millions?) of years.

I mean, Manhattan may be under water in 100 million years (or, much sooner), but all those gigantic steel, concrete, plastic and glass structures aren't just going to dissolve.

digitaltrees• 6 years ago

Wouldn’t glaciers grind them to dust?

ChuckMcM4• 6 years ago

I would guess that glaciers would encapsulate the skyscrapers and dislodge them from their foundation, and when they receded leaving a huge pile of steel and concrete. Even if that was later encapsulated by magma, future geologists would have to wonder about metal 'veins' that were so structured and why part of the rock was basalt and another part was an exceptionally hard and dense form of limestone.

Note to self. Don't speculate on HN. Got it. :-)

lmilcin• 6 years ago

There is better argument and it is surface natural resources.

We know, that before industry took off we had huge amount of natural resources almost lying on the ground. Now many of crucial resources have to be dug from huge depths or recovered from dilute sources.

I can't imagine a previous industrial civilization leaving huge amount of resources available on the surface. Almost by definition, industry is about scaling and efficiency and it always look to get to the results as quickly as possible.

api• 6 years ago

Depends on time frame. Plate tectonics will reset things quite a bit over truly vast time scales.

Over shorter time scales this argument mostly holds, though one can imagine an intelligence with technology but with less expansionary drive and conspicuous consumption than humans. This intelligence may use resources more slowly.

a1369209993• 6 years ago

To be fair, industrial-level civilization (engines, mass production, etc) doesn't actually require large, reinforced concrete structures[0].

That said, the answer to TFA's question is "almost certainly yes, unless they deliberately tried to conceal geological evidence of their existence, and probably even then".

0: nor vice versa, technically, though the logistics of using pre-industrial steel as building material would be prohibitive. see https://news.ycombinator.com/item?id=24591216

gus_massa• 6 years ago

The steel doesn't last too much, this link claims only 1200 years. https://www.quora.com/How-long-can-stainless-steel-last-for#....

I'm not sure about that number, but the ancient the bronze swords are better conserved than the steel ones.

Plastic will get washed away, and glass may get crunched and be difficult to find.

The rest of the concrete has a longer lifetime.

matchagaucho• 6 years ago

The Authors seem to be saying a visit to a barren planet shouldn't be written off as "no life".

Evidence of civilization could be just below the surface.

divbzero• 6 years ago

It sounds like “gigantic steel, concrete, plastic and glass structures aren’t just going to dissolve” really depends on timescale, and geologic timescales are far beyond our typical experience.

From the Atlantic article by one of the authors: [1] [2]

When it comes to direct evidence of an industrial civilization—things like cities, factories, and roads—the geologic record doesn’t go back past what’s called the Quaternary period 2.6 million years ago. For example, the oldest large-scale stretch of ancient surface lies in the Negev Desert. It’s “just” 1.8 million years old—older surfaces are mostly visible in cross section via something like a cliff face or rock cuts. Go back much further than the Quaternary, and everything has been turned over and crushed to dust.

[1] https://www.theatlantic.com/science/archive/2018/04/are-we-e...

[2] https://news.ycombinator.com/item?id=24601382

nabla9• 6 years ago

In periods of 100s of millions of years whole continents disappear or move around, new layers of rocks are formed and old layers are buried. The Rocky Mountains formed just 55 - 80 million years ago.

Cities disappear completely. Concrete and glass becomes rock (again), steel is oxidized and is just layer of iron ore. Plastics degradate and breaks into nanoparticles.

As the article speculates, most evidence would be likely something like synthetic biomarkers in deep sea sediments. Traces of industrial chemicals not produced naturally. Wrong chirality in some organic chemicals. Transuranic elements.

friendlybus2• 6 years ago

Some zircons have been dated back to the hadean era, when the earth was forming. Any information for building something that sticks around long term would be contained in them.

analyte1232• 6 years ago

There are plenty of places within a two hour drive or train ride from NYC where you can see gigantic steel concrete and brick structures that are less than 150 years old well into the process of dissolving. If you live in prosperous cities and don’t have to maintain property, it’s understandable how you can be unfamiliar with the relentless processes of rust, melt-freeze weathering, erosion, storm damage, how quickly vegetation grows, and so on.

ncmncm8• 6 years ago

Every time this pops up on HN, people post insisting that it won't all go away, that the skyscrapers will, somehow, still be there.

No, they won't. Look at any place in the world where there are mesas. All of the land around the mesa used to be level with the top of the mesa. It has all eroded away, and in only a few million years.

So, the metals will corrode, collapse, and wash away. The stone will erode away. The concrete will erode away. The radioactives will decay. It will all end up as a millimeter-thick layer on the sea bottom, one of thousands of millimeter-thick layers with nothing to call attention to itself. Microplastics will abound, but somebody needs to be looking for them in exactly that layer, the way we found iridium at the K-T boundary layer, after specifically looking. There is a huge overabundance of platinum (parts-per-billion) in layers only 12900 years old, just discovered in the past decade, and only because we are really interested in that layer. (It was the start of the 1300-year Younger Dryas cold spell whose end is the start of the Holocene Epoch.)

Will anything last? Big mining and quarry pits will fill in, but recognizably. Big mine tunnels will fill in or collapse, but recognizably. A rectangular mine shaft dug down through a thousand meters of sedimentary rock will have no other explanation.

Some structures will be buried, instead of eroding away. Those will be deep underground, and then might be exposed again through subsequent erosion or uplift. Again, a brick chimney found buried will have no other explanation, though people will try.

Strictly speaking, one is all you need, but some people ("people"?) need more convincing.

imglorp• 6 years ago

Has anyone methodically looked for artificial materials like microplastics in the geological strata?

Retric5• 6 years ago

Yes, in that people try and identify what’s there. No, in that it’s not expected to find evidence of a prior advanced civilization. The prior existence of oil as an easily recoverable resource is a strong indicator that nothing like our civilization existed in the last several million years.

opportune• 6 years ago

We know about the KT extinction layer (which contains a lot of iridium, a potentially extremely useful but rare metal) but attribute it to meteorite ejecta. It also coincided with large scale climate and environmental changes. That's the only candidate I know of as a non-geologist.

saltedonion• 6 years ago

Is total human/intelligent species population not a prerequisite for industrialization. If so, we would expect to see a lot of fossilized remains, which we have not seen.

ncmncm8• 6 years ago

We have found exactly one (1) skeleton of a Clovis person, the dominant human culture of North America for several centuries, right up until exactly the start of the Younger Dryas cold spell, only 12900 years ago.

pmiller22• 6 years ago

Those people need to watch a few episodes of the TV series Life After People. Watching it, and realizing that everything around us would literally start to fail in a matter of days without us as its caretakers, really brought home the impermanence of everything. Skyscrapers are certainly not going to outlast ancient cave dwellings. In a matter of a couple hundred years, I would be surprised if a single skyscraper was still standing without us to keep it up. I’ve seen unmaintained buildings falling a part after a mere decade of disuse; a skyscraper lasting for a century or two would be extremely durable on the scale of modern buildings.

friendlybus2• 6 years ago

Nobody is building for the super long term, we expect on some level that new will replace the old at some point.

This man is trying to build a clock to last 10k years. https://longnow.org/clock/

jlawson2• 6 years ago

I wonder how long the Egyptian pyramids would last.

reachfortheskyy• 6 years ago

For what it's worth, the Spivey Building is almost 100 years old and it's been abandoned since the '50s.

https://en.wikipedia.org/wiki/Spivey_Building

St. Louis has a lot of cool abandoned architecture, although you might want to be careful wandering around East of the river.

I wonder how many cities have abandoned towers that became historical places thanks to longstanding traditions of not being able to afford a demolition.

Veedrac2• 6 years ago

This argument disproves fossils.

E: To be pedantic, it only disproves most fossils.

TeMPOraL6• 6 years ago

And, as predicted by the argument, the fossils don't abound, and to find them you have to start digging.

jandrese2• 6 years ago

At one level yes, most everything built will disintegrate with time, but we have fossilized footprints from dinosaurs. An industrial society disappearing without a trace seems unlikely. Although the vast majority of the evidence would be lost there will always be traces left if you know what to look for.

withinboredom2• 6 years ago

The thing is, it’s probably unbelievable when you do find evidence. https://archaeology-world.com/200-million-year-old-shoe-prin...

ALittleLight2• 6 years ago

The dinosaurs lived for a couple hundred million years. An industrialized society might last a few thousand.

pmayrgundter3• 6 years ago

I strongly agree with this take.

I've been working on a paper comparing the effects of the Anthropocene to mega catastrophes in the geologically recent past. In addition to the Younger Dryas Impact (12kya), there's the Oruani (26kya) and Mt Toba (77kya) eruptions. From my calculations, it seems the climate change from each of these dwarfs any actions humans are currently capable of, namely petrocarbon burning and also total nuclear war.

I'm also critical of the account given to these events in the IPCC reports.

It seems unbelievable to me that the climate change debate isn't considering these more, so I'm still debugging the numbers and research. But happy to take comments from anyone who's interested!

https://docs.google.com/document/d/1yo9yHMfEnEepefDCRdar-B-4...

ncmncm8• 6 years ago

Previous catastrophes did not vent the millions of tons of hydrofluorocarbons into the atmosphere that we will, that break down into a greenhouse gas thousands of times as potent as CO2. (We thought switching from CFCs to HFCs would save us. Joke's on us!) The total of HFCs currently in circulation, eventually leaked or vented, will produce as much greenhouse effect as all the CO2 currently in the atmosphere. (A sharp minority of the responsible people collect it for disposal.) So, it's not just CO2.

The US is supposed to switch from HFCs to something else around 2024. A lot of companies are switching to propane refrigerant ahead of time because it's cheaper, and worry about it igniting has dissipated, vs. looming ecological catastrophe.

BTW, to my knowledge the Greenland structure has not been reliably dated, nor even confirmed to be a bolide crater (although it seems like one). YD bolide impact seems pretty secure, though.

Temperature change might be a relatively minor effect of the CO2 concentration peak. Ocean acidification causing a collapse at the base of the food web, as marine animals become unable to fix calcium to make shells, might be more important.

ancientworldnow• 6 years ago

The earth is warming at a rate of four Hiroshima bombs per second [1] primarily because of human actions. I haven't read your document but it sounds like you're grossly underestimating our energy output.

[1] https://archive.thinkprogress.org/earths-rate-of-global-warm...

neffy• 6 years ago

I think you're right, if you take the extreme events that have happened on this planet - and arguably the ice ages themselves also belong there, human activities haven't yet produced anything of that magnitude.

The question is how many more years do you want to give it until we do. These are huge slow systems we are looking at, at the point there is clear evidence around us that disaster is on the horizon, it is already several decades too late to do anything about it.

bufferoverflow2• 6 years ago

Some structures should survive millions of years in dry buried conditions. Like bank vaults made of thick stainless steel buried in Arizona.

yongjik• 6 years ago

Forget skyscrapers, instead consider this: footprints. You likely made millions of them in your life. How many of them still exist? Approximately zero. It's hard to think of something more ephemeral.

Yet dinosaur footprints have been fossilized. They're found all around the earth.

I'm sure our civilization has already created a gazillion things more permanent than them.

jlawson2• 6 years ago

Yeah, but consider the base rate. Even if the things we create are more permanent that footprints, there are just so many footprints that some of them, by unbelievable triple-corner case coincidences, end up here for us. Even if the chance per footprint is really low, there are so many of them made over the course of hundreds of millions of years that it doesn't matter. Our 100 year industrial history is nothing compared to that.

rmtech3• 6 years ago

If someone starts looking they will find this layer containing plutonium-244 (which is made by nuclear explosions, 80 million year half life) and microplastics, and yeah that will make it pretty obvious. But I think you're right that if it was even 5 million years in the future you would really have to be looking for it.

yxhuvud3• 6 years ago

I strongly doubt microplastics would survive heat and pressure well enough to not revert back to oil/gas/coal.

tobinfricke• 6 years ago

Abstract: "If an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record. We then propose tests that could plausibly distinguish an industrial cause from an otherwise naturally occurring climate event."

jakeogh• 6 years ago

Excellent yt chan: vlad9vt, just pictures of artifacts and structures set to music https://youtu.be/EHFe10dp0L4

AareyBaba• 6 years ago

Evidence for ancient machining technology : Saw cuts, tube drill holes etc https://youtu.be/6KUDu40BC5o?t=1197

ffhhj2• 6 years ago

A highly responsible civilization that achieves space fairing tech could rebuild its environment, leaving a clean planet as a gift for future species to emerge, and move to the stars. Sort of artifical-creationism, but phycally achievable, it's a matter of civilization goals.

Zhenya• 6 years ago

Why would they spend resources doing this?

ffhhj2• 6 years ago

Maybe morality, madness, a form of art, investment, or just-because-we-can...

TeMPOraL6• 6 years ago

To give the next species a chance to grow?

While a stretch as a motivation, the Uplift saga by David Brin has this as a core point: ecology and biodiversity is important for all the species in these books; planets are leased and used for a while, and then lain fallow to let them regrow and potentially spawn more sentient beings that could then (be helped to) join the galactic community.

foxdev• 6 years ago

Otherwise you get species popping up later to find the device one of your people left that kills you in the plane of existence you transcended to.

https://en.wikipedia.org/wiki/Stargate%3A_The_Ark_of_Truth

mjevans• 6 years ago

Related, I highly recommend the videogame Outer Wilds, which notably includes a 22 min timeloop, and, related to this I'll add a tiny spoiler; an extinct civilization that was responsible enough to not wreck the ecology of a world that could have intelligent life in their future.

pmiller22• 6 years ago

I’ve always loved this paper, for its particular combination of heterodoxy and emphasis on testable hypotheses. There are so many things we don’t know about past human civilizations that have left non-geological markers (who were the “Sea People,” the full story of Petra, tons of undeciphered ancient scripts, etc.) that it doesn’t seem terribly strange that an industrial civilization could have bloomed, died, left few traces, and what traces they did leave are the kind only a geochemist or paleoclimatologist might notice.

stephc_int13• 6 years ago

If we can detect traces of life (fossils) I am pretty sure we can detect traces of many of the artefacts produced by an industrial civilization.

crispyporkbites• 6 years ago

I don’t know much about detecting traces of ancient civilisations, but I can definitely detect traces of someone who didn’t read the paper in your comment.

aurizon• 6 years ago

What areas on the earth have already endured for 65 million, 100 million,200, 300, 400, 500 million years already without changes? Obviously many areas have been subducted via plate tectonics and after volcanic transformation at depth would leave no artifacts. Would you find gold rings on dinosaur fingers? Gold watches? We know gold can endure, and if these prior saurian techies had adornments, they may end up in sediments that can endure. How to find them? Catscans and MRI imaging could show dense metallic residues in some cases. So far there have been scans done on a few fossils, but if they were not looking for residues of artifacts, such residues may not have attracted attention. Funerary buildings? Pyramids are only a few thousand years old and many millions would turn them to dust on the surface, and subducted ones = melted away. There has been time for a 200 million year old race to be very very hard to find - except on the moon's surface? If there was a moon project 200 million years ago, would gradual meteoric impacts over this time period have buried them beyond finding? Direct impacts would have destroyed them utterly. Indirect impacts gradually bury the surface of the moon with impact scattered rock powder. We know the moon is deeply cratered and has a deep coating of impact dust. Metal landers would endure and gradually get some feet of accumulated dust, but various metal detectors would find them - but a huge area would need to be searched. I assume good dino-engineers would use aluminum and titanium instead of steel/iron, so ferrous metal detectors would not work. Even good detectors of conductors are good for only a few feet. So we may never find evidence of the war between the warlike dinosaurs of earth versus the Insectoids of Ganymede - that was won so decisively by the insectoids 65 million years ago with their impactor...

sunstone• 6 years ago

Sure if they were fond of atmosperic testing of nuclear weapons.

Animats2• 6 years ago

The oldest hard-rock mountains are 1.5 billion to 3.5 billion years ago. Those include some heavily mined areas, such as the Appalachians, If a previous civilization had been into serious mining, we'd probably have seen evidence of that by now. There may be nothing left of the mine, but an area without the good stuff and the remains of a big rubble dump would be interesting.

Conversely, a concentration of rusted metal is not likely to occur naturally.

phendrenad2• 6 years ago

Wouldn't metal dissolve over thousands of years? I'd be on the lookout for plastics.

Animats2• 6 years ago

You'll get rust, but huge piles of concentrated iron oxide in a low erosion zone are not found much in nature.

nobody9999• 6 years ago

Wouldn't metal dissolve over thousands of years? I'd be on the lookout for plastics.

That's not a bad idea, but finding synthetic isotopes[0] with extremely long half-lifes[1] (e.g., Tellurium-128) would clinch the deal.

[0] https://en.wikipedia.org/wiki/Synthetic_radioisotope

[1] https://en.wikipedia.org/wiki/List_of_radioactive_nuclides_b...

samatman3• 6 years ago

That, and the real smoking gun: landfillite.

Some significant fraction of landfills are going to fossilize into a pretty distinctive sedimentary rock. I don't know what it would look like, but it would have, like, fossil Barbie dolls in it.

I don't think we'd have missed all of them if they existed. We could postulate an industrial civilization which just didn't make landfills? But we've only got ours to go on, and we really like burying trash. If our hypothetical forbearers were anything like us, we'd know about them.

tsomctl• 6 years ago

I don't think so. Landfills are a source of many important minerals and energy. I'm convinced that we'll be mining ours in the next couple of centuries.

justinclift• 6 years ago

Don't plastics degrade into (effectively) petroleum oil or similar stuff on a geologic time scale?

rbrbr• 6 years ago

Isn’t a much easier way to look around our planet and search for satellites of past civilizations? Or even on the moon where everything lasts much longer. Long after we and everything of us is gone from this planet moon vehicles and other devices which were left there will likely still be there unless a meteorite hit them.

yissp• 6 years ago

I don't think satellites stay in orbit for very long - like a few decades at the very most.

treis• 6 years ago

Depends on their orbit. LEO will see drag from the atmosphere and will fall from orbit relatively quickly. Geostationary satellites will orbit basically forever.

rtsil• 6 years ago

Depends on the orbit. Elon's roadster on its heliocentric orbit has a predicted half-life of 15 million years (1)

The moon has been on orbit around the earth for billions of year and will probably remain on orbit forever (whatever "forever" means).

(1) https://www.mdpi.com/2226-4310/5/2/57

Frost1x• 6 years ago

I'd say the moon would be an obvious candidate to look at, though no guarantees.

redisman• 6 years ago

That’s where you hide the first obelisk

theossuary• 6 years ago

Well, according to Mass Effect, we should really be looking at mars

viach• 6 years ago

Maybe be the remains of ancient civilizations could be found on orbit? Satellites can stay on geostactacionary orbit for a very long time. Some of them are sent to the "graveyard orbit" the radius of which was the same for Earth even millions years ago. Did anyone actually compared the number of objects there with the number of satellites we made?

titzer3• 6 years ago

FTA: "The likelihood of objects surviving and being discovered is similarly unlikely. Zalasiewicz (2009)speculates about preservation of objects or their forms, but the current area of urbanization isless than 1% of the Earth’s surface (Schneider et al., 2009), and exposed sections and drillingsites for pre-Quaternary surfaces are orders of magnitude less as fractions of the original surface.Note that even for early human technology, complex objects are very rarely found. For instance,the Antikythera Mechanism (ca. 205 BCE) is a unique object until the Renaissance. Despiteimpressive recent gains in the ability to detect the wider impacts of civilization on landscapesand ecosystems (Kidwell, 2015), we conclude that for potential civilizations older than about 4Ma, the chances of finding direct evidence of their existence via objects or fossilized examples oftheir population is small. "

These people have clearly never been to the beach--any beach. The oceans are absolutely chock full of our garbage and it is being deposited not only on the ocean floor, but on every shoreline the world over, where much is ground up and still more silted over. Plastic trash wafts the world over. Everything from beer cans to glass bottles to cars to aircraft are strewn through the entire industrialized world, in forests, creeks, and backyards. We have landfills the size of small towns. There are thousands of shipwrecks all over the oceans. Bazillions of items will be fossilized and preserved, and the odds of stumbling over something just digging anywhere will be very high.

This article is completely full of shit. Humans have left their mark and our junk is going to be here, fossilized, for eternity. If we've discovered hundreds or thousands of fossilized dinosaurs from over 100 million years ago, when there might be only a few thousand such skeletons even to be found, there's a damn good bet that someone is going to find one of the tens of billions of beer cans or beer bottles that are lying around, even if only a tiny fraction survive the aeons.

kadoban• 6 years ago

You've provided a good argument that it's obvious _right now_ from our junk that we live here, but what of that do you expect to last, and how long? Pick a type of object or two and let's look into how they are expected to last and what they'll look like.

Fossilization isn't a universal process, there's no such thing as a fossilized beer can.

kevin_thibedeau• 6 years ago

Anything corrosion resistant that ends up entombed in geologically stable strata will stick around. There will be lots of anamolous ceramic and glass mixed in with the fossilized human bones strewn about.

Andrew_nenakhov• 6 years ago

Thing is, unlike dinosaur bones, beer can or bottle can't survive for aeons.

metiscus• 6 years ago

but styrofoam lasts forever /s

For sufficiently short values of forever.

titzer3• 6 years ago

Sure they can, if surrounded by stable strata in the same way that dinosaur bones were. In fact, beer cans can bottles won't be broken down by natural biotic processes; they just need to be protected from erosive forces.

user4682• 6 years ago

There are changes in the geological record that are still unexplained, these could be signs of an older civilization.ld

"The Younger Dryas was a period of rapid cooling in the late Pleistocene 12,800 to 11,500 calendar years ago. It followed closely on the heels of a dramatically abrupt warming that brought the last Ice Age to a close (17,500 calendar years ago), lasted for about 1,300 years, then ended as abruptly as it started. The cause of these remarkably sudden climate changes has puzzled geologists and climatologists for decades and despite much effort to find the answer, can still only be considered enigmatic."

https://wattsupwiththat.com/2012/06/19/the-intriguing-proble...

monkeydreams• 6 years ago

You are posting a climate-change denying site as your source for this? Consider me incredulous.

Edit: From my quick perusal, the warming for the Younger Dryas period is not mysterious at all. The main theory is that there was a sudden cooling due to the failure of the Atlantic meridional overturning circulation around 12,900 BC. This cooling was then rapidly reversed back to the median warming trend about 11,700BC.

ncmncm8• 6 years ago

You have just pushed the mystery back a step. What caused the failure of the Atlantic meridional overturning circulation? What reversed the failure 1200-odd years later?

Evidence for a bolide strike producing a huge meltwater pulse, to start the process, is accumulating, coinciding with extinction of 30+ genera and the sudden end of the Clovis culture. Another strike at the Holocene boundary is less well supported; but we do need a cause.

dboreham• 6 years ago

There would be a thin layer of highly compressed shoes.

thaumasiotes• 6 years ago

Considering we can measure Roman metal production by the pollution it left in ice deposits in Greenland, I'd have to say "yes".

timoth3y• 6 years ago

It more convincing to look at it the other way.

It's not what such civilizations would have left, but what they would have taken.

Our early civilizations found easily accessible deposits or tin, copper, gold, etc that would have been depleted if another advanced civilization had existed in the past 10 million years or so.

ksdale• 6 years ago

"Depleted" in this case would just mean mined, transported, and made into something. It doesn't seem farfetched to imagine that, say, an electronics factory would be reduced to an easily accessible deposit of copper or gold in a few million years.

nitwit005• 6 years ago

It depends how long the civilization is around. A lot of metal could end up impractical to mine. You can recycle metals, but little chips are being lost to wear and corrosion over time. We're slowly spreading small amounts everywhere.

Some of that would be theoretically be recoverable with a lot of effort and energy, but some of it will basically be gone. No one is going to get back small bits of metal fallen off ships into the deep ocean.

oh_sigh• 6 years ago

Tin was actually very hard to find. Which is a huge problem for civilizations that wanted to be a part of the Bronze age. Most of the tin used in Europe and western Asia was mined from just a few places in England, France, and Spain. if you find an Assyrian weapon from the 12th century BC in northern Iraq, it shouldn't surprise you if you find it was forged with tin mined in Cornwall.

74ls00• 6 years ago

IIRC tin was one of main motivating factors for the Roman invasion of Britain

cozzyd• 6 years ago

Oil, especially, would probably be less common if there was an ancient industrial civilization.

yxhuvud3• 6 years ago

If there was one involving humans, sure. Involving dinosaurs (or earlier)? No. Oil is constantly reforming and the oil we drill today wouldn't have formed back then. Sure, we suck it up a LOT faster than the replenish rate or the rate of natural reintroduction of fossilized carbohydrates into the circulation, but over geological timespans oil has a best-before date. Eventually there will be fissures (due to land movement or erosion) and it would end up being released onto the surface in one way or another.

lazyjones• 6 years ago

Our early civilizations found easily accessible deposits or tin, copper, gold, etc that would have been depleted if another advanced civilization had existed in the past 10 million years or so.

Perhaps they also found remains of other advanced civilizations and axploited those?

10 million years is nothing in geological terms.

jccooper• 6 years ago

Yes, over geologic time, nearly anything has no chance of survival. And, yes, the lifetime of such a civilization may be a window that is, geologically, basically invisible.

But an industrial civilization makes a LOT of stuff, and much of that is quite durable and easily recognizable as artificial, and is likely to be scattered all over the planet.

Given that there are places that preserve tracks over 300 million years old, and fossils, well, up to 4 billion years old, I have a hard time imagining that a worldwide civilization that's producing and using aluminum and titanium and ceramics and all sorts of other stuff on a wide basis would not leave something recognizable in basically all the available fossilizing environments. We might not ever find fossils of the species, but are we really not going to find anything from the million refuse dumps and cities and industrial facilities and whatnot, or millions of miles of roads, or the multi-billions of accidental losses bound to be all over the world?

Not to mention objects in high orbit or on the lunar surface, which is a whole other thing.

You have to posit a really limited civilization before I believe it.

JoeAltmaier3• 6 years ago

It wouldn't take a complex material to recognize a previous civilization. Their civil engineering activities would give them away completely.

Archaeologists can read worked surfaces with amazing skill. E.g. a bed of pebbles could be a lake bed, a road surface, a floor inside a building, a foundation, and there's ways to distinguish them.

Unless the soil was erased/reformed completely there would be a record of almost any activity, from digging a post hole or trench, to building a wall then removing it again then dumping construction waste into the hole then plowing it under. All are different from 'native' soils deposited by random processes.

Geologic time is not enough to erase evidence of worked soils. Not unless it gets scrubbed to the bedrock and redeposited. And even if that happened some places, it wouldn't happen every place. And its fair to say today, that our civilization has been pretty much every place.

sjy4• 6 years ago

Geologic time is certainly enough to erase evidence of worked soils. It spans billions of years, the destruction and formation of continents, and multiple global mass extinctions. Archaeology concerns only the last few million years of hominid activity.

sjy4• 6 years ago

The paper addresses this objection in section 1.3: “That this paper’s title question is worth posing is a function of the incompleteness of the geological record … The oldest extant large-scale surface is in the Negev Desert and is ~1.8 Ma old. However, pre-Quaternary land-evidence is far sparser, existing mainly in exposed sections, drilling and mining operations. In the ocean sediments, due to the recycling of ocean crust, there only exists sediment evidence for periods that post-date the Jurassic (~170 Ma).”

ardit332• 6 years ago

that is disingenuous... and is just word playing with definitions.

Most mountains in Europe have surfaced with the last 10-20 mill years, and they have turned earth around to the point that you routinetly find marine fossis in top of 2000m mountains.

If any civilization was around, it would have left a mark somewhere, and mountains would be a great place to spot them.

BTW: According to most scientists, the oldest mountain range on Earth is called the Barberton Greenstone Belt and is found in South Africa. It's estimated that the range is at least 3.2 billion (yes, billion!) years old.

candiodari2• 6 years ago

Yeah but I bet there's, even now, like 80-90% (guess) of the planet that don't have a single manmade object on them.

And those million/billion years tracts of land that archaeologists see are like 0.0000001% (guess) of the total. Odds seem good that surviving rocks came from very boring, very pointless places.

markwkw• 6 years ago

Some tongue-in-cheek ideas: Stockpile of synthetic diamonds

A few cemeteries could make for curious fossils

Mines - some caves survived for 200+ million years. Conceivably a part of a mine somewhere could survive, with concrete structural reinforcements and parts of non-corroding tools intact

WalterBright• 6 years ago

Impressions of leaves are common in coal. Fossilized remains of industrial society would have been found by now.

filoeleven2• 6 years ago

One of my favorite quotes from Iain M. banks’ Culture series, paraphrased here since I don’t recall which book it’s in, is that technological progress is more like scaling a rock face than climbing a ladder. There is so much room for surprise and incomprehension.

I sometimes think about how vast the parameter space of our physical universe is, and if that vastness means we wouldn’t be able to recognize ancient advanced technology if it’s far enough outside of our current mode of progress.

My favorite example is handing an SD card with all of Wikipedia and the Gutenberg Project and maybe even the Wayback Machine on it to a Roman emperor. He’d look at it and might have a mild interest in the geometrical metal bits on an otherwise insignificant tiny flake of weird material. If the deliverer were to tell him that it contained millions of documents, he wouldn’t believe it.

An expert in the field of storage media could, if for some reason permitted, spend years trying to explain it to the scholars of the time. Even if the expert succeeded in convincing them, it would take an unimaginable effort lasting lifetimes to ever make use of the thing. It would not succeed. Not because those people were stupid, but because the specialization that’s needed to understand the artifact is so far away from from their cultural knowledge and capabilities as to be unreachable. Why should we expect our culture be any different?

The primary counter-argument to this is math and physics, and it’s a pretty strong one. It holds up quite well when dealing with past civilizations that are beneath or somewhere close to our current level of understanding. If you’ll permit another flight of fancy though, imagine an ancient society that figured out how to encode information in the irregularities of crystalline structures: every lame-ass quartz medallion we’ve unearthed could be the equivalent of a 10TB hard drive, and we’d never be the wiser.

I think this is pretty unlikely, but it’s good to be humble and interrogate your assumptions.

jacobr1• 6 years ago

My favourite example came from my 9th grade physics class, our textbook told a story that attempted to teach scientific method. Imagine a soda vending machine. Now imagine that I tell you that when you insert money and press the buttons, small goblins are can see what buttons are being pressed, take the money and it put it in a box, and then hand you the selected soda. The textbook even had helpful diagrams that seemed plausible (presuming you had such creatures). Now tell me why this is or isn't so ... and prove it even! How many of you have ever opened up or observed a vending machine (well, on HN I bet that number is surpassingly high, but presume you haven't). It was fantastic exercise in intellectual humility.

For your SD Card example though, I'll nitpick. Sure, just a card and explanation won't get you very far ... but I think something like an iPad (with a good power-supply) would produce enough evidence to convince them (depending upon the individual, I grant there might be some who just attributed it to supernatural forces even in the face evidence and explanation). I suspect humans in general are more willing to deal with "blackbox" technology that has practical application than most tinker types on HN would admit. Very little historical technology that was hard earned with trail-and-error has a theoretical basis known to even skilled practitioners. Even today, to most most people I know, the technology they use on a daily might as well be magic. Sure they know there some kind of "science" beyond it, but I'm also not sure they could convince me it wasn't just goblins if I demanded some theory of it worked.

throwanem• 6 years ago

I mean, one of the first major papers about supercapacitors from back in the late 50s, early 60s, something around that, included a line like "we don't know what's actually going on inside this component when we use it this way, but it sure does store a lot of energy, here's how to make one".

There's nothing shocking or unreasonable or even old-fashioned about understanding what something does before we wonder why it does it. In fact, I'm pretty sure the origin of almost all human knowledge has been precisely in questions of exactly that sort.

zaphirplane• 6 years ago

Why do you think that an old civilization with deeply held beliefs of gods, magic, seers, oracles ... etc find it hard to believe that a library worth of books has been shrunk down. There is only a small window where magic/gods was being supplanted by monotheistic dogma that is plausible. On the other hand you tell me this dot contains the total sum of knowledge and I’d be nice ... or a drop of this liquid would destroy a solar system I’d be where is the lid

mongol4• 6 years ago

What would persuade them? It would be really hard to explain how it would be possible.

eru2• 6 years ago

What people profess to believe in and how they act are two different things.

filoeleven2• 6 years ago

There’s a huge difference between belief in an artifact as holding magical powers and the expectation that you could make practical use of it.

I might be wrong about the emperor’s belief. I chose an SD card particularly because it looks insignificant. Getting an emperor to say “this is a sacred relic” is still a long way off from getting an emperor to say “let us endeavor to unlock the secrets of this relic.”

codeulike• 6 years ago

One of my favorite quotes from Iain M. banks’ Culture series

Its from "Matter"

Hippense cleared his throat and said, "The type of progress you guys are used to doesn't scale into this sort of civilisational level; societies progress until they Sublime - god-like retirement, if you will - and then others start again, finding their own way up the tech-face. But it is a tech-face, not a tech-ladder; there are a variety of routes to the top and any two civs who've achieved the summit might well have discovered quite different abilities en route. Ways of keeping technology viable over indefinite periods of time are known to have existed aeons ago, and just because something's ancient doesn't mean its inferior."

jula432vdf• 6 years ago

As far as we know, quasars could be fully artificial, and around them you could find some of our future friends.

and those things would be pretty outdated - ancient - technology by time we spotted them.

sjy4• 6 years ago

I’m never sure whether to trust arXiv papers outside my field, so I checked and found that the paper was published in the International Journal of Astrobiology, and the PDF is open access: https://www.cambridge.org/core/journals/international-journa...

8bitsrule2• 6 years ago

There have been many civilizations on Earth, maybe not many were industrial (ancient Egypt was clearly semi-industrial so far as lithic tooling is concerned.)

We haven't looked deep enough very much. Many of the 10-25,000 year sites are buried dozens of feet underground. If there are any previous ruins, they're probably a hundred-or-more feet down. Seaside ruins from 10k+ years ago are now under 400 feet of water and 10k+ years of sediment. We've just started to notice evidence of major changes only 13k years back ... with more on the way.

Over 100,000 years, water has scoured (and deeply buried) much of the surface. Consider the number of glaciations in the past 2M years ... each one of which has scoured the surface in northern regions repeatedly. Much farther back than that, and most geo- and bio-records are erased.

The planet's dynamics would have scrubbed almost anything before 10 million years ago. There've been 400 of those; 5 major extinctions left some traces. The scale of upheavals has been massive. How long ago did the Andes arise? It was first noticed in the 1700s that Whole sections of the Earth's surface have gone missing. https://en.wikipedia.org/wiki/Hutton%27s_Unconformity

ardit332• 6 years ago

ok... i get your point, but the major counterpoint:

as earth / plate tectonic move around, underneath earth is constantly surfaced... from dinosaur fragments, to Cambrian era mollusks found in top of mountains (due to earth's crust movement).

If there was a previous 'intelligent' civilization previous to us, they would have altered their environment to be detectable to us even today.

candiodari2• 6 years ago

Exactly. Mullusks. Think of them like ants. Almost exclusively small dinosaurs. Things that would have been everywhere, including many places civilization would never choose to go. They are things that would be much more widespread than gameboys (just giving an example).

8bitsrule2• 6 years ago

OK then let's find it. We're not really looking. Maybe it is indeed detectable, and maybe it will be hard. Maybe it's already staring us in the face, and our ideas about it are -wrong-.

We -believed- the Clovis story. Until some people -looked harder-. Plate tectonics ... laughed at. Until some people -looked harder-. Absence of evidence is not evidence of absence.

rmtech3• 6 years ago

Yes, it will definitely be possible via hundreds of different pathways, some of which they thought of in the paper and others that they didn't.

The Anthropocene layer in ocean sediment will be abrupt and multi-variate, consisting of seemingly concurrent specific peaks in multiple geochemical proxies, biomarkers, elemental composition, and mineralogy. It will likely demarcate a clear transition of faunal taxa prior to the event compared to afterwards. Most of the individual markers will not be unique in the context of Earth history, but the combination of tracers may be. However, we speculate that some specific tracers that would be unique, specifically persistent synthetic molecules, plastics, and (potentially) very long-lived radioactive fallout in the event of nuclear catastrophe.

One that they didn't mention was our artifacts on the moon which will last 100 million years or so. Geostationary and HEO satellites will stay for a while but I'm not exactly sure how long.

However if you wait 50 million years or so, most of the stuff on earth won't be obvious and you would need to check very carefully.

dvdkhlng• 6 years ago

One that they didn't mention was our artifacts on the moon which will last 100 million years or so. Geostationary and HEO satellites will stay for a while but I'm not exactly sure how long.

Erosion due to micrometeorites erodes the surface of the moon at 1mm per 1e6 years [1]. I wonder whether erosion of human-made moon artifacts will commence at a comparable rate.

Note that the hull thickness of the apollo lander is just 0.3 mm [2]. Part of the propulsion system, tanks etc. would be the components to last longest, butt 100 million years may be quite a stretch.

[1] https://mauricejscollins.wixsite.com/moonscience

[2] https://space.stackexchange.com/questions/924/what-would-hav...

rmtech3• 6 years ago

Well, 100mm is not that much, I suspect there is something in all that stuff that is at least that thick. Maybe the bags of excrement? That would be pretty funny.

Would it be possible to detect an industrial civilization in geological record?

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