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?
Wondering about this as well. INAG, but I think fossils are extremely rare relative to population. And things like wedding rings will have disintegrated after just a few million years. But still, you'd think some of them would survive under conditions similar to those that preserved dino skeletons?
That was my thinking as well, though apparently geologists are pretty pessimistic about both the survival of human artifacts and the probability that someone would find the rare oddballs that did survive.
Plus, it’s possible that some hypothetical dino civilization mastered bio-degradable materials early on before taking to the stars ;-)
"Dinosaurs on a Spaceship" was mildly disappointing given the amazing ridiculousness of the title, but "The Hungry Earth" / "Cold Blood" is a top-notch two-part episode. It feels so authentically human in both the highs and the lows.
They discuss that in the article. Essentially everything would be turned asunder by the changing of the earths crust. The oldest part of the earths crust is something like 1.7 million years.
If I'm not mistaken, Greenland has crust from over 3 billion years ago. 1.7 million years ago is nothing, I don't know where you got that number from but it is wrong.
As does much of northern Canada. However, the ancient rock, billions of old as it may be, wasn't surface rock 1.7 million years ago. It's only been surfaced since through erosion.
“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 refers to ancient surface, as in, the oldest place that we can find that has continuously been an exposed surface. The take away is that most areas don't remain stable at the surface, either they erode away, or get buried via sedimentation.
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).
All comments in a thread based on an article should be read in that context. Unless, of course, the links are never followed and we’re just here to massage each other’s preconceptions.
In Gene Wolfe's SF/fantasy tetralogy The Book of the New Sun, set very far in the future, he refers to corpses preserved by extreme means and rendered essentially indestructible and basically just cluttering up the world.
Not trying to be pedantic but the devil is in the details.
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.
Given that pillow lavas can be recognised in some eclogite facies rocks, I think a porcelain toilet would stand a good chance of remaining recognisable at all the way to granulite or eclogite facies, as long as it is not too deformed.
This is kind of the "why aren't we all buried in bones" question that YECs raise. Very little makes it into the fossil record -- fossilization is sensitive to a lot of different conditions, and then someone's gotta find it later besides.
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.
Right, I had fossils like that as a kid too, and even had a friend with a ranch in the East Bay that had an exposed fossilized seabed with lots of fossilized shells.
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.)
I had some interest in this question a decade or two back. What I found from my searches was that it was thought that some human-made ceramics were tough enough to last a million years, pretty much nothing else. How much longer, IDK. Ice sheets will wipe out large structures like the dams and pyramids, but how long will it take to destroy or scatter the remains so that they are not recognizable?
Sure, but that doesn't make it immune to the passage of time.
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.
Mesoamerican gold was looted and melted down wholesale (along with a lot more silver) by the Spanish. The artefacts were considered unchristian and so were deliberately destroyed, and this has meant that we have barely a fragment of the artistry of the Inca and Aztec.
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.
The process of fossilization by definition replaces organic material with very hard minerals. The fossils we find today are the ones that by chance have fossilized into the hardest minerals under the best conditions for preservation -- buried in the right kind of mud at the time, or by tar more recently, or in ice, or in a bed of limestone.
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.
Gold is soft but Amber is softer and we've found intact insects encased in that substance which are 230 million years old*. You wouldn't be likely to find a complete car or something in 60 million years but there will certainly be plenty of artifacts which were preserved through sheer luck. I wouldn't be surprised if most small manifactured objects would survive in archeologically recognizable form if they were accidentally lost in an anoxic environment. For example, imagine you lose your iPhone when out in a swamp. Drop a phone in something as thick as Pluff Mud, which is abiotic below the surface, and you've basically encased it in the exact kind of environment which has produces the best fossils we've yet found.
My thought is how likely is it that crustal movements would bury things too deep on that timescale? If stuff stayed near the surface, that's one thing, but would it?
We also see things trapped in glaciers, but if the timescale is large enough for all the glaciers to have melted...
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.
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.)
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.
