1. Ancient civilization enters industrial and post-industrial era.
2. Carbon levels rise, so do global temperatures.
3. In a desperate attempt to save themselves they try geo-engineering by slamming a massive asteroid in the too hot and thus unpopulated area of Yucatan.
4. Goes wrong.
I can see it working as sci-fi novel
Which means maybe we should be a bit more careful about bleating our existence out into the universe these days...
"We've been sitting in our tree chirping like foolish birds for over a century now, wondering why no other birds answered. The galactic skies are full of hawks, that's why. Planetisms that don't know enough to keep quiet, get eaten".
- bacteria with engineered enzymes for recycling (https://news.ycombinator.com/item?id=16856246) mutate/go wild and wipe out most/all traces of civilization
- what we can find today is just slightly elevated levels of whatever these bacteria mostly ignored.
https://pubs.geoscienceworld.org/gsa/geology/article-abstrac...
“Fifty-six million years ago, Earth passed through the Paleocene-Eocene Thermal Maximum (PETM). During the PETM, the planet’s average temperature climbed as high as 15 degrees Fahrenheit above what we experience today. It was a world almost without ice, as typical summer temperatures at the poles reached close to a balmy 70 degrees Fahrenheit. Looking at the isotopic record from the PETM, scientists see both carbon and oxygen isotope ratios spiking in exactly the way we expect to see in the Anthropocene record. There are also other events like the PETM in the Earth’s history that show traces like our hypothetical Anthropocene signal. These include an event a few million years after the PETM dubbed the Eocene Layers of Mysterious Origin, and massive events in the Cretaceous that left the ocean without oxygen for many millennia (or even longer).”
Also, how long would it take for the oceans to reabsorb that oxygen? Do the current records follow these expectations?
Perhaps there are proxy signals? For example, there's ocean re-oxygenation faster (or slower?) than expected? Could a species that required more oxygen tip the scales?
Plus, it’s possible that some hypothetical dino civilization mastered bio-degradable materials early on before taking to the stars ;-)
Invasion of the Space Dinos!
http://tardis.wikia.com/wiki/Dinosaurs_on_a_Spaceship_(TV_st...
Wasn't the article more meaning "the oldest part of the earths crust, that's still on the surface"?
eg everything else has been buried, or destroyed, via other geological processes
“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 farther than the Quaternary and everything has been turned over and crushed to dust.”
The article is in no way stating the oldest bit of the Earth's crust is 1.8 million years old. Crust has a specific meaning, the chemically differentiated rocks at the surface i.e. everything but the very very rare bits of exposed mantle. Oldest oceanic crust is <200 Ma, oldest continental crust dates to the Hadean (4.4 Ga, if you set the bar at only zircons).
Bones are common, fossils are formed by a relatively rare geologic process. Fossilization supplants slow to rot organic material with stone, embedding it in the strata, in just the right conditions. It's unclear to me what (if any) industrial rememants would become fossilized and if they'd be recognizable as such.
Going past a few tens of thousands of years, fossils start to either be of very large things, or of very large communities of small things.
I'd be surprised if any future scientists could find even a single piece of modern jewelry a million years from now.
Granted the coral fossil in the living room is many small animals, but it’s not a big object.
But typically those are extracted from deposits with lots of similar pieces, like the three-foot-long slab of fossilized seabed I had. Professionals might carefully carve something like that up and turn it into lots of small fossils of fish, but they all came from the same chunk of rock.
That's what I meant by "large communities of small things".
So, it's possible that some bunker of physical storage of wealth, with gold bars for instance, will survive a hundred thousand years longer than most of the rest of our civilization. Or, maybe one of our many many landfill deposits will end up with just the right conditions to preserve for a long time the preservable stuff. But I don't think bits of gold jewelry will just be sifted out of the dirt.
Come to think of it, the best bet for evidence of our civilization a million years from now are currently the bits we've left behind on the moon, and Musk's roadster! (The latest calculations have a 6% chance of it crashing back to Earth within the next 3.5 million years -- but it will continue to swing back around every hundred years or so until then.)
Take Mesoamerican gold for instance: only about a thousand years have passed since much of it was made by humans, but it's still considered a rare and valuable archaeological find. (Granted, it was produced in smaller quantities than today.)
Gold is melted by fires; gets scattered and buried by a million years of bioaccumulation; seas move, rivers appear or disappear, continents drift a little, climate changes, glaciers come and go and further destroy evidence.
Google is feeding me a lot of really dumb stuff at the moment when trying to come up with numbers, but I'd guesstimate that most traces of our civilization would be buried a hundred feet below the surface after a million years' time. That makes it pretty difficult to find small things.
There is some hope though! It's thought that the melting process was done in Spain so as to allow a reliable royal assay, if so then some of the ships that sank in the trade may have holds full of crushed and squashed precious artefacts.
I can find one not-great reference suggesting that carbon fiber items are expected to be in landfills for on the order of hundreds of years -- not very long in geological scales. Steel rusts and degrades spectacularly easy, and a lot of the steel we've produced is exposed to conditions helping it along.
Neither of these items is susceptible to the process of fossilization; it's that process that helps preserve some things for a long time. The stuff we make has to last that long all by itself, and we're not that good at making things yet.
We also see things trapped in glaciers, but if the timescale is large enough for all the glaciers to have melted...
(I was going to raise the same point, thinking of low-background steel and the effects of nuclear testing on our atmosphere, but after some more reading it appears that most of those isotopes decay over shorter periods or weren't sufficiently elevated to be discernible from the background, if it were being examined in the far future.)
Article on Wikipedia: https://en.m.wikipedia.org/wiki/The_Ice_People_(Barjavel_nov...
Highly recommended! At least from my recollection!
Geostationary is only stationary in relation to a specific point on earth (geo). It just means it stays above a point on earth. It requires regular minor adjustments.
L1, L2, and L3 aren't stable. L4 and L5 are... but you would still need to adjust for the earth and moon not being perfect spheres; the moon moving slowly away from earth; tidal variations; solar wind; debris; etc.
L4 and L5 would last the longest, but not 60m years.
Someone else mentioned the objects we've placed on the moon. Seems to me that those would last the longest. The moon gets hit by small meteorites daily, but nothing that would destroy what's up there.
Nuclear reactors are recognizable for their crazy isotope distributions for billions of years. Geosynchronous sattelites might be stable for that long, too. The anthropocene mass extinction is likely to show up in the fossil record, and the rapid climate change based on burning carbon out of the ground (which doesn't match the isotope mix of atmospheric carbon) will likewise be detectable from sediment.
I am giving a talk on my Masters project this week at the University of Hartford. I was doing some background reading a found this thread and your comment! Interestingly the Atlantic published article last year abut a new report (Nature Scientific Reports) that hinges on my Masters work: https://www.theatlantic.com/science/archive/2017/11/the-exti...
We need to have a beer some time and catch up!
Turning sci-fi into science speaks volumes to your creativity and intellectual capacity to run an idea to ground.
Wastes, particularly those that get everywhere such as plastics.
I am told that one long-term marker of human presence on earth at this time is that strata being laid down at present contain small pieces of plastics.
See "The geological cycle of plastics and their use as a stratigraphic indicator of the Anthropocene" https://www.sciencedirect.com/science/article/pii/S221330541...
Also:
"Human impact has created a 'plastic planet'" https://www.sciencedaily.com/releases/2016/01/160127083854.h...
http://www.newsweek.com/theres-even-more-plastic-ocean-floor...
https://www.theguardian.com/environment/2017/feb/17/tiny-pla...
edit Even though it will change over time into something other than plastic,
1) it will affect the composition of rocks being formed now
2) through sheer ubiquity, some of it is likely to enter into the fossil record.
I think that we might be more likely to find concentrations of metals left over from artifacts of civilization. If so, would these look different from naturally occuring metals?
"microplastics everywhere". http://www.bbc.co.uk/news/science-environment-43363545
"Microplastic pollution in oceans is far worse than feared, say scientists", "pervasive and persistent nature" https://www.theguardian.com/environment/2018/mar/12/micropla...
"The deep sea is a major sink for microplastic debris" http://rsos.royalsocietypublishing.org/content/royopensci/1/...
We don't know what the effect of millions of years on this debris will be, but I am suggesting that due to the fact of the human species as a geological force, most of the rocks from this era will be a bit unusual in composition.
Your best bet for metals might be gold as it is not typically reactive with water or oxygen. And as a reminder, we do sometimes find solid blobs of gold... :-)
I also agree that the I-beams would rust away, as would rebar embedded in concrete. Would they remain as identifiable shapes or would the material migrate?
Also has a computer RPG [1] by some of the people behind Planescape: Torment.
Though, I'll grant it's possible they could've been soft-bodied creatures that leave very little in the fossil record or might otherwise look ambiguous to us. A future civilization looking back on human fossils might think we lived no differently than any other Hominidae. Anatomically modern humans have been around for ~2.5 million years, if our civilization were to end in even another couple million years that would still be a fairly tiny window in which we developed the intelligence to create civilization and then went extinct. If some jellyfish species developed human-level intelligence 300 million years ago and then went extinct in the same window, it's entirely possible we wouldn't be able to recognize the difference between their fossils and those of their less intelligent ancestors/descendants.
What we can't know is if someone aimed it there.
I wonder if a swarm of artificial satellites that are little more than time capsules on various highly stable orbits, combined with radioactive markers/beacons on the moon that is arranged to somehow point towards the swarm, might survive that long? The moon's orbit is stable on the order of billions of years [1], but surface impacts might bury any artifacts we leave, so radiation is likely the only way an artifact can stand out millions of years from now.
If the swarm is a solid procession of one satellite passing near the Earth once every 50 years, then the markers' arrangement might be able to point to that intersection somehow. Bonus points if we can figure out passively-controlled, self-repairing solar sails for better detection. I haven't sketched the math yet though, so I don't know if we're talking about more satellites than we can create (would more than likely require von Neumann mining bots on an asteroid to produce, and definitely more mass than we can realistically lift at this time).
This has the advantage of letting us continuously launch updated capsules, as well as capture and update probes (like modifying a massive continuous loop) if our civilization lives that long.
I really Iaian Banks' idea of a civilization "restart button": deep space-resident AI-manned ships that all but just wander and hibernate within vast gulfs of vacuum, equipped with the tech necessary to reboot their civilization, and run silent all the time except when they opt-out of the service. That requires AGI and a fictional inexhaustible energy source to pull off, so we have to settle for what we can do for now.
[1] https://astronomy.stackexchange.com/questions/19658/what-def...
https://en.wikipedia.org/wiki/Yucat%C3%A1n#Origin_of_%22Yuca...
While this is marked as "citation needed", given the information provided, it seems illogical to prefer one of the other explanations just because it sounds more amusing.
Also see: https://en.wikipedia.org/wiki/Chontal_Maya which seems to at least confirm the term "Yokot'an" exists.
It is probably specious reasoning to assume that the name originated at the moment the Spanish first met the indigenous people, but it seems to be such a good story that most don't question it, even when they are debating the different possibilities.
Footprints from the Apollo missions can still be seen.
Anyways, I was thinking that the metal from the spacecraft wouldn't have gone through the weathering/oxidation that anything man-made still on earth would go through.
Even if some of them will get covered by dust and some get destroyed by asteroid impacts, the others will remain visible.
You don't get a better anoxic environment than space!
Maybe we are just looking in the wrong place for our evidence. ;)
While any particular structure has a very low probability to be preserved in 60M years, some specimens of ubiquitous artificial structures have reasonably good odds of survival. Something like a coke bottle would more likely signal a part industrial civilization.
Some years ago a friend of mine coily posed this same question to me
In this part, I think you meant coyly which has a different meaning from coily.
I am reminded of the famous talk by Richard about "where does fire come from, where does. plant get Carbon, well it gets it from the AIR, and it grabs water from the earth, and the flame that you see in fire is the energy from the sun being released!" (Paraphrasing, [0] )
so my point is, that if you look at Plant Life distribution and look at all of South America, with their dense rain-forest plant biome - you have a crap ton of plants which may have had the ability to absorb more carbon based on the Yucatan crater (gulf of Mexico) and thus thrive based on the abundance of the carbon flood that happened during this impact.
[0] https://www.youtube.com/watch?v=ifk6iuLQk28
This is the best explanation of fire/plants/atmosphere that I have ever heard.
---
Question:
Why would oil concentrations happen in the places they do over many billions of years?
So why would the seemingly devoid-of-water places on earth (Middle East) be oil rich, where, at the same time, South America also has oil rich deposits?
The idea being that they are carbon-rich underlayments that become oil under pressure.
Or, how "soluble" (for lack of a better term) is carbon in Magma. i.e. how can carbon be dealt with in a magma stream other than heat and pressure which results in oil deposits over time?
So, any geologists who can educate me would be appreciated.
This article is beginning to convince me:
https://www.upi.com/Vast-expanse-of-melting-carbon-found-ben...
estimate the amount of carbon trapped in Earth's upper mantle. Scientists suggest there's as much as 100 trillion metric tons of CO2 stored there.*
So based on this data point and the comments from Richard, I think that life is a function much like the sodium-potassium pump, and oil is a function of the subduction plate tectonics which converts carbon to oil over millennia....
We will always have oil. Just how fast can we consume vs. how fast can earth produce. Supply and demand is a. universal constant.
/speculation.
It turns out my friend had put a LOT of thought into this exact question. Enough to do a masters in geology, his work ultimately making it into a high profile journal with writeups in places like the NY Times.
He started talking to various geologists about what might survive as telltale markers of our civilization. Buildings or structures of any sort? Ha! Statues and monuments? Maybe we’d notice the odd deposit or two of minerals.
After going through a long list of candidates, he settled on carbon cenospheres. These are little balls of carbon almost exclusively made in internal combustion engines as the result of aerosolizing fossil fuels. Sixty million years ago, our love of the ICE will show up in the fossil record as a light dusting of cenospheres covering the earth—contemporaneous with massive numbers of species going extinct due to mankind’s other influence.
And as my friend was telling me his story, this is where my hair stood on end. Sixty million years ago we see a massive species extinction... and a light dusting of carbon cenospheres covering the globe.
But we also see unnatural levels of iridium at the same point. And, while it’s hypothetically possible some industrial civilization was mining iridium and blanketing the globe with it, it’s more probable that the iridium was delivered by an asteroid.
But how would you know? So my friend, as part of his research, went taking samples of his cenospheres from around the globe. What he found was interesting: namely, the further one gets from the Yucatan (where scientists had already validated there was an asteroid strike), the cenospheres get smaller. The big heavy ones precipitated out of the air closest to the Yucatan asteroid strike. Hardly likely to be coincidence.
So much for ancient civilization this time around.
However, his work rewrote a critical understanding of the KT asteroid extinction event. Namely, we previously thought most of the carbon at the KT boundary was the result of giant forest fires ignited by the strike. However we now know that the strike must have aerosolized massive oil fields under the Yucatan at that time and set them ablaze.
Not a bad contribution to science starting from a sci-fi premise!