11 ms·

This is one of my all-time favorite “what if” questions. Some years ago a friend of mine coily posed this same question to me: What does humankind make that wou

This is one of my all-time favorite “what if” questions. Some years ago a friend of mine coily posed this same question to me: What does humankind make that would survive 60 million years into the future, and if some other advanced industrial civilization had existed 60 million years ago, how would we know? 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!

ianai 9y ago
He’s not too far off what this article suggests as a marker of civilization in the past. But they have positives! “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).”
- chiefalchemist 9y ago
  What happens to the atmosphere when you suck all the oxygen out of the oceans? 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?
jules 9y ago
Wouldn't you find human artifacts all over the place even 60 million years from now? We have fossils much older than that, so wouldn't many many objects like gold wedding rings be around 60 million years from now?
- dorchadas 9y ago
  I don't think any of that would necessarily be indicative of civilization, though.
- i_am_nomad 9y ago
  Yes, absolutely. The article is borderline clickbait. If there were a technological civilization on Earth in the past, we would have detected it by now. Concentrations of radioisotopes, industrial ceramics, signs of large excavations in the fossil record... those are just a few.
  - coldtea 9y ago
    Those are just few that presuppose it would have to be an industrial civilization at our level ("concentrations of radioisotopes")...
  - thaumaturgy 9y ago
    Radioisotopes decay; which isotopes are you thinking of that have half-lives of millions of years and would be found in detectable quantities? (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.)
    - garmaine 9y ago
      Radioisotopes decay, but it is the ratio that is important. We know, for example, that a natural (we assume?) nuclear reactor occurred in Africa 1.8bn years ago due the different isotopic concentration of uranium deposits from that era.
maxerickson 9y ago
Here's the paper: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/36/5/355/29701/combustion-of-fossil-organic-matter-at-the https://pubs.geoscienceworld.org/gsa/geology/article-abstrac...
- peatmoss 9y ago
  That’s the one! I was hoping someone would be interested enough to fact check me :-)
deleted 9y ago
[deleted]
wklauss 9y ago
> Not a bad contribution to science starting from a sci-fi premise! 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
- elorant 9y ago
  If you write it, I'll buy it.
- vivekseth 9y ago
  This reminds me of the movie Snowpiercer
- sudhirj 9y ago
  As far as geo-engineering goes, I think what they'd be wanting to do is cause a super-volcano or three. You really don't want to be pulling asteroids down - just a couple of finely place nukes will do. Get a volcano going, put a few tons of sulphur in the air and you have a nice cooling effect. Just be careful of the unintended tsunami. Should probably just evacuate Iceland and keep popping the volcanoes until it's cool again.
  - chiefalchemist 9y ago
    Is there any theory that suposes this might happened, on a small scale, and the temps (and crust) warm? Could that loosen things up, so to speak, and trigger more volcanic activity?
- justinclift 9y ago
  Perhaps the asteroid was just an asteroid mining operation gone horribly wrong, or some form of planet killing warfare?
- snowwrestler 9y ago
  Maybe the Earth-based technological civilization attracted the attention of a space-faring civilization, who dropped an asteroid to wipe out the Earth civilization (successfully, as it turns out). Which means maybe we should be a bit more careful about bleating our existence out into the universe these days...
gedy 9y ago
I'm confused though - the oldest fossils are 3-4 Billion years old? Is the hypothesis that we just haven't stumbled on creatures of this time?
- peatmoss 9y ago
  Sure, the KT event isn’t the result of ancient civilization, there's nothing saying we couldn’t have had civilization at some other point in time, or that didn’t leave a record noticeable to us from that time.
- trentnix 9y ago
  They cremated their dead for fear their decaying bodies would corrupt the Earth (or their karma or their gods or whatever). And voila, they're gone.
  - aalleavitch 9y ago
    This is implausible; you're assuming that every civilizational stage from every point in this hypothetical species development would have had the same burial practices? 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.
robotomir 9y ago
What about the ring of debris in geostationary orbit? Will that decay in 60M years?
- jobigoud 9y ago
  And the stuff at the Lagrange points, assumedly in rather stable orbits.
  - rgbrenner 9y ago
    To answer both of your questions: none of that stuff will be in orbit in 60m years. 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.
    - acover 9y ago
      Could you move in a moon orbit?
      - rgbrenner 9y ago
        Same problem. I don't think it could be in orbit. 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.
    - pocketstar 9y ago
      >none of that stuff will be in orbit in 60m years. where will it go? it wouldn't have the drag or the delta-v to reenter. i think the parent meant geostationary altitude, but "geostationary" orbits are "relatively" cyclically stable. most significant perturbations, you mentioned some, are all <100 year cycles. If there was another spacefaring civilization >60m years ago i think there would be evidence, in orbit.
yourapostasy 9y ago
> What does humankind make that would survive 60 million years into the future, and if some other advanced industrial civilization had existed 60 million years ago, how would we know? 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-defines-a-stable-orbit https://astronomy.stackexchange.com/questions/19658/what-def...
IncRnd 9y ago
Interesting. Thank you for that. 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.
- peatmoss 9y ago
  Yup, my undergrad journalism profs would be moritified. In my defense, it was early and I was still working on my first coffee.
  - IncRnd 9y ago
    If I had a penny for each time I used the wrong word I'd be riff.
justinator 9y ago
What about artifacts on the Moon?
- valuearb 9y ago
  Long since buried by moon dust.
  - justinator 9y ago
    I'm unclear why they would be buried, there's no Moon-wind storms as far as I know. 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.
    - antisthenes 9y ago
      Long poles anchored everywhere around the moon. 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!
    - cfadvan 9y ago
      Moon artifacts would be there for a very very long time, and yes there would be no burying, techtonic activity, or oxidizing. Only impact events and solar wind really change the moon, the former is rare now and the latter insignificant. Evidence of a human presence on the moon will be there for potentially at least a billion years. The footprints might last that long, and actual artifacts made of metal (including gold) surely will.
yoda_sl 9y ago
Over 20 years ago, I read a good sci-fi story which I would love to see in a movie; the book is “The Ice People” by Barjavel (French author). Article on Wikipedia: https://en.m.wikipedia.org/wiki/The_Ice_People_(Barjavel_novel) https://en.m.wikipedia.org/wiki/The_Ice_People_(Barjavel_nov... Highly recommended! At least from my recollection!
- srge 9y ago
  Excellent book
SideburnsOfDoom 9y ago
> if some other advanced industrial civilization had existed 60 million years ago, how would we know? 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/S2213305416300029 https://www.sciencedirect.com/science/article/pii/S221330541... Also: "Human impact has created a 'plastic planet'" https://www.sciencedaily.com/releases/2016/01/160127083854.htm https://www.sciencedaily.com/releases/2016/01/160127083854.h... http://www.newsweek.com/theres-even-more-plastic-ocean-floor-its-surface-292715 http://www.newsweek.com/theres-even-more-plastic-ocean-floor... https://www.theguardian.com/environment/2017/feb/17/tiny-plastic-pellets-found-on-73-of-uk-beaches 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.
- snowwrestler 9y ago
  I have a hard time believing plastics will persist as plastics. It doesn't take much heat to denature most plastic, and geologic sediments tend to experience a good bit of pressure and heat over time.
  - SideburnsOfDoom 9y ago
    I doubt that they will be the same after a few million years, no. But what kind of rock will it make? Won't it be unlike anything else?
    - HankB99 9y ago
      Aren't plastics hydrocarbons? Would the hydrogen be driven off (cracked) leaving something like coal. 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?
ajross 9y ago
> What does humankind make that would survive 60 million years into the future 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.
- danmaz74 9y ago
  But I suppose that the weird isotope distribution caused by nuclear reactors affects areas so small, that they would be incredibly unlikely to be detected?
  - ajross 9y ago
    It's not like you can smell it, but these things exist (from natural fission chain reactions, not progenitor civilizations!) and have been discovered: https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
darkerside 9y ago
I'm sure it's a dumb question, but it's a genuine one. How do we know that the Yucatan crater is from an asteroid, and not from some kind of man-made explosion created by an advanced civilization?
- Hussell 9y ago
  Basically: because it has a lot of characteristics in common with all the other, better preserved, asteroid craters we know of. So our hypothetical advanced civilization would have to have deliberately mimicked all the little details of an asteroid impact, not just created a big explosion using some other method. That's possible, of course, and if they did it well enough we'd never know. But it seems much more plausible that it was an asteroid impact.
  - saratogacx 9y ago
    Maybe they had started asteroid minding and in an attempt to bring one into local orbit, it went horribly wrong.
- ianai 9y ago
  Bomb explosions look fundamentally different from meteorites. Both may be modeled by modern tech.
- BurningFrog 9y ago
  It's definitely an asteroid. What we can't know is if someone aimed it there.
analogmemory 9y ago
Fun fact, Yucatan means "I do not understand". https://en.wikipedia.org/wiki/Yucat%C3%A1n#Origin_of_%22Yucat%C3%A1n%22 https://en.wikipedia.org/wiki/Yucat%C3%A1n#Origin_of_%22Yuca...
- perl4ever 9y ago
  The page provides several alternatives, ending with "the Chontal Maya people refer to themselves as the Yokot'anob or the Yokot'an, meaning "the speakers of Yoko ochoco." Thus Yucatan most likely derives from Yokot'an." 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 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.
samstave 9y ago
"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." 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 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-beneath-Western-United-States/3701487004861/ 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.
AlexCoventry 9y ago
You might enjoy Marooned In Real Time, in which a few humans accidentally persist 50 million years past the seeming annihilation of the rest of the human race.
DoreenMichele 9y ago
One of my favorite sci fi stories posited that the civilization was centered on the land that is currently Antarctica and the disaster that destroyed it shifted the earth, moving that continent to the South Pole. Prior to the event, it was a lush South American style landscape. Maybe we are just looking in the wrong place for our evidence. ;)
Razengan 9y ago
If you love fictional settings based on such concepts, check out Numenera [0]: A "hyper sci-fi" set a billion years in the Earth's future, after at least 8 great civilizations have come and gone, leaving the planet covered with the effects and remnants of incomprehensible technology. Also has a computer RPG [1] by some of the people behind Planescape: Torment. [0] http://numenera.com http://numenera.com [1] https://www.gog.com/game/torment_tides_of_numenera https://www.gog.com/game/torment_tides_of_numenera
nine_k 9y ago
We dig up numerous and various animal remains from dozens of millions of years ago. Some are pretty well preserved. 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.
wharfbanger 9y ago
Hi Peter, 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-extinction-of-the-dinosaurs-was-very-unlikely/545378/ https://www.theatlantic.com/science/archive/2017/11/the-exti... We need to have a beer some time and catch up!
- peatmoss 9y ago
  I hope it was okay to share your story! It's honestly one of the most inspirational science research stories I know of. Turning sci-fi into science speaks volumes to your creativity and intellectual capacity to run an idea to ground.

ianai 9y ago

He’s not too far off what this article suggests as a marker of civilization in the past. But they have positives! “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).”

chiefalchemist 9y ago
What happens to the atmosphere when you suck all the oxygen out of the oceans? 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?

jules 9y ago

Wouldn't you find human artifacts all over the place even 60 million years from now? We have fossils much older than that, so wouldn't many many objects like gold wedding rings be around 60 million years from now?

dorchadas 9y ago
I don't think any of that would necessarily be indicative of civilization, though.
i_am_nomad 9y ago
Yes, absolutely. The article is borderline clickbait. If there were a technological civilization on Earth in the past, we would have detected it by now. Concentrations of radioisotopes, industrial ceramics, signs of large excavations in the fossil record... those are just a few.
- coldtea 9y ago
  Those are just few that presuppose it would have to be an industrial civilization at our level ("concentrations of radioisotopes")...
- thaumaturgy 9y ago
  Radioisotopes decay; which isotopes are you thinking of that have half-lives of millions of years and would be found in detectable quantities? (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.)
  - garmaine 9y ago
    Radioisotopes decay, but it is the ratio that is important. We know, for example, that a natural (we assume?) nuclear reactor occurred in Africa 1.8bn years ago due the different isotopic concentration of uranium deposits from that era.

maxerickson 9y ago

Here's the paper: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/36/5/355/29701/combustion-of-fossil-organic-matter-at-the https://pubs.geoscienceworld.org/gsa/geology/article-abstrac...

peatmoss 9y ago
That’s the one! I was hoping someone would be interested enough to fact check me :-)

deleted 9y ago

[deleted]

wklauss 9y ago

> Not a bad contribution to science starting from a sci-fi premise! 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

elorant 9y ago
If you write it, I'll buy it.
vivekseth 9y ago
This reminds me of the movie Snowpiercer
sudhirj 9y ago
As far as geo-engineering goes, I think what they'd be wanting to do is cause a super-volcano or three. You really don't want to be pulling asteroids down - just a couple of finely place nukes will do. Get a volcano going, put a few tons of sulphur in the air and you have a nice cooling effect. Just be careful of the unintended tsunami. Should probably just evacuate Iceland and keep popping the volcanoes until it's cool again.
- chiefalchemist 9y ago
  Is there any theory that suposes this might happened, on a small scale, and the temps (and crust) warm? Could that loosen things up, so to speak, and trigger more volcanic activity?
justinclift 9y ago
Perhaps the asteroid was just an asteroid mining operation gone horribly wrong, or some form of planet killing warfare?
snowwrestler 9y ago
Maybe the Earth-based technological civilization attracted the attention of a space-faring civilization, who dropped an asteroid to wipe out the Earth civilization (successfully, as it turns out). Which means maybe we should be a bit more careful about bleating our existence out into the universe these days...

gedy 9y ago

I'm confused though - the oldest fossils are 3-4 Billion years old? Is the hypothesis that we just haven't stumbled on creatures of this time?

peatmoss 9y ago
Sure, the KT event isn’t the result of ancient civilization, there's nothing saying we couldn’t have had civilization at some other point in time, or that didn’t leave a record noticeable to us from that time.
trentnix 9y ago
They cremated their dead for fear their decaying bodies would corrupt the Earth (or their karma or their gods or whatever). And voila, they're gone.
- aalleavitch 9y ago
  This is implausible; you're assuming that every civilizational stage from every point in this hypothetical species development would have had the same burial practices? 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.

robotomir 9y ago

What about the ring of debris in geostationary orbit? Will that decay in 60M years?

jobigoud 9y ago
And the stuff at the Lagrange points, assumedly in rather stable orbits.
- rgbrenner 9y ago
  To answer both of your questions: none of that stuff will be in orbit in 60m years. 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.
  - acover 9y ago
    Could you move in a moon orbit?
    - rgbrenner 9y ago
      Same problem. I don't think it could be in orbit. 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.
  - pocketstar 9y ago
    >none of that stuff will be in orbit in 60m years. where will it go? it wouldn't have the drag or the delta-v to reenter. i think the parent meant geostationary altitude, but "geostationary" orbits are "relatively" cyclically stable. most significant perturbations, you mentioned some, are all <100 year cycles. If there was another spacefaring civilization >60m years ago i think there would be evidence, in orbit.

yourapostasy 9y ago

> What does humankind make that would survive 60 million years into the future, and if some other advanced industrial civilization had existed 60 million years ago, how would we know? 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-defines-a-stable-orbit https://astronomy.stackexchange.com/questions/19658/what-def...

IncRnd 9y ago

Interesting. Thank you for that. 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.

peatmoss 9y ago
Yup, my undergrad journalism profs would be moritified. In my defense, it was early and I was still working on my first coffee.
- IncRnd 9y ago
  If I had a penny for each time I used the wrong word I'd be riff.

justinator 9y ago

What about artifacts on the Moon?

valuearb 9y ago
Long since buried by moon dust.
- justinator 9y ago
  I'm unclear why they would be buried, there's no Moon-wind storms as far as I know. 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.
  - antisthenes 9y ago
    Long poles anchored everywhere around the moon. 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!
  - cfadvan 9y ago
    Moon artifacts would be there for a very very long time, and yes there would be no burying, techtonic activity, or oxidizing. Only impact events and solar wind really change the moon, the former is rare now and the latter insignificant. Evidence of a human presence on the moon will be there for potentially at least a billion years. The footprints might last that long, and actual artifacts made of metal (including gold) surely will.

yoda_sl 9y ago

Over 20 years ago, I read a good sci-fi story which I would love to see in a movie; the book is “The Ice People” by Barjavel (French author). Article on Wikipedia: https://en.m.wikipedia.org/wiki/The_Ice_People_(Barjavel_novel) https://en.m.wikipedia.org/wiki/The_Ice_People_(Barjavel_nov... Highly recommended! At least from my recollection!

srge 9y ago
Excellent book

SideburnsOfDoom 9y ago

> if some other advanced industrial civilization had existed 60 million years ago, how would we know? 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/S2213305416300029 https://www.sciencedirect.com/science/article/pii/S221330541... Also: "Human impact has created a 'plastic planet'" https://www.sciencedaily.com/releases/2016/01/160127083854.htm https://www.sciencedaily.com/releases/2016/01/160127083854.h... http://www.newsweek.com/theres-even-more-plastic-ocean-floor-its-surface-292715 http://www.newsweek.com/theres-even-more-plastic-ocean-floor... https://www.theguardian.com/environment/2017/feb/17/tiny-plastic-pellets-found-on-73-of-uk-beaches 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.

snowwrestler 9y ago
I have a hard time believing plastics will persist as plastics. It doesn't take much heat to denature most plastic, and geologic sediments tend to experience a good bit of pressure and heat over time.
- SideburnsOfDoom 9y ago
  I doubt that they will be the same after a few million years, no. But what kind of rock will it make? Won't it be unlike anything else?
  - HankB99 9y ago
    Aren't plastics hydrocarbons? Would the hydrogen be driven off (cracked) leaving something like coal. 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?

ajross 9y ago

> What does humankind make that would survive 60 million years into the future 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.

danmaz74 9y ago
But I suppose that the weird isotope distribution caused by nuclear reactors affects areas so small, that they would be incredibly unlikely to be detected?
- ajross 9y ago
  It's not like you can smell it, but these things exist (from natural fission chain reactions, not progenitor civilizations!) and have been discovered: https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...

darkerside 9y ago

I'm sure it's a dumb question, but it's a genuine one. How do we know that the Yucatan crater is from an asteroid, and not from some kind of man-made explosion created by an advanced civilization?

Hussell 9y ago
Basically: because it has a lot of characteristics in common with all the other, better preserved, asteroid craters we know of. So our hypothetical advanced civilization would have to have deliberately mimicked all the little details of an asteroid impact, not just created a big explosion using some other method. That's possible, of course, and if they did it well enough we'd never know. But it seems much more plausible that it was an asteroid impact.
- saratogacx 9y ago
  Maybe they had started asteroid minding and in an attempt to bring one into local orbit, it went horribly wrong.
ianai 9y ago
Bomb explosions look fundamentally different from meteorites. Both may be modeled by modern tech.
BurningFrog 9y ago
It's definitely an asteroid. What we can't know is if someone aimed it there.

analogmemory 9y ago

Fun fact, Yucatan means "I do not understand". https://en.wikipedia.org/wiki/Yucat%C3%A1n#Origin_of_%22Yucat%C3%A1n%22 https://en.wikipedia.org/wiki/Yucat%C3%A1n#Origin_of_%22Yuca...

perl4ever 9y ago
The page provides several alternatives, ending with "the Chontal Maya people refer to themselves as the Yokot'anob or the Yokot'an, meaning "the speakers of Yoko ochoco." Thus Yucatan most likely derives from Yokot'an." 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 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.

samstave 9y ago

"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." 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 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-beneath-Western-United-States/3701487004861/ 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.

AlexCoventry 9y ago

You might enjoy Marooned In Real Time, in which a few humans accidentally persist 50 million years past the seeming annihilation of the rest of the human race.

DoreenMichele 9y ago

One of my favorite sci fi stories posited that the civilization was centered on the land that is currently Antarctica and the disaster that destroyed it shifted the earth, moving that continent to the South Pole. Prior to the event, it was a lush South American style landscape. Maybe we are just looking in the wrong place for our evidence. ;)

Razengan 9y ago

If you love fictional settings based on such concepts, check out Numenera [0]: A "hyper sci-fi" set a billion years in the Earth's future, after at least 8 great civilizations have come and gone, leaving the planet covered with the effects and remnants of incomprehensible technology. Also has a computer RPG [1] by some of the people behind Planescape: Torment. [0] http://numenera.com http://numenera.com [1] https://www.gog.com/game/torment_tides_of_numenera https://www.gog.com/game/torment_tides_of_numenera

nine_k 9y ago

We dig up numerous and various animal remains from dozens of millions of years ago. Some are pretty well preserved. 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.

wharfbanger 9y ago

Hi Peter, 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-extinction-of-the-dinosaurs-was-very-unlikely/545378/ https://www.theatlantic.com/science/archive/2017/11/the-exti... We need to have a beer some time and catch up!

peatmoss 9y ago
I hope it was okay to share your story! It's honestly one of the most inspirational science research stories I know of. Turning sci-fi into science speaks volumes to your creativity and intellectual capacity to run an idea to ground.