85,000-year-old Finger Bone Complicates Understanding of African Migration
smithsonianmag.com
smithsonianmag.com
This finding is only significant because of the age, but have we ever verified our dating techniques over 5k years? 10k years? What’s to say that the hot desert sun and strange weather patterns, radiation or whatever couldn’t skew the dating and mean this bone is just some traveller from a mere 1-2k years ago.
It seems further unlikely that such a bone from, 85k y/ago as they say, would be so close to the surface.
Ftn In mechanical engineering we don’t ever “trust” the calculations until they are thoroughly validated with ie strain gauges. And more often than not we discover our assumptions were wrong. So I suppose a similar thing applies here in dating science, except, it’s impossible to validate for another thousand centuries. It seems backwards to hinge all our science on it when (AFAICT) it hasn’t even been validated itself!
https://www.usu.edu/geo/luminlab/whatis.html
https://en.wikipedia.org/wiki/Luminescence_dating
I'm not an expert in the subject an I'm not an archeologist, but the method sounds good.
One of the parts is the decay of radioactive atoms. This is a very well known subject, it's very easy to model and it is not affected by pressure or temperature (unless you use ridiculous huge amounts).
The other part is about electrons trapped in the defects of crystals, and the conduction and valence band of crystals. This is also a well known subject, but it's more difficult to model. So IIUC after measuring the amount of "trapped" light they must irradiate each sample to calibrate the "trapping" ability of the material. This is not affected by usual variations of pressure and temperature. In particular the energy of the photons in sunlight is very different from the photons due to normal levels of heat. (At high temperature like more than 500°C or 900°F, that is possible near a fire, the difference between the energy of the photons is not so much and you have https://en.wikipedia.org/wiki/Thermoluminescence_dating . But the heat below a few inches of the floor under sunlight is not enough.)
As I said, I'm not an expert, but it looks like they are combining well known techniques and I guess that if you can enclose a bunch of Ph.D. students in a lab for 20 years with proper equipment, a few interesting samples and enough food, they will be able to rediscover this method.
If you want to find something shady here, I'd look at
> [Katerina] Harvati, who wasn’t involved in the research, said she would be cautious in definitively assigning the finger fossil a Homo sapiens identity due to the fact that its shape overlaps with other hominin species. [...]
Also I have no problem with the biology aspect as it is trivially verified what a human (or otherwise) bone looks like, composition etc
Buried finger in sand.
At night. (thus leaving the sand 'unbleached' as the term is used in the optical luminescence field.)
Occam's razor.
Quite a trick for some dude in a caravan 100 years ago to be able to simulate 85,000 years of radioactive decay.
I don't think it is usually the constant decay rate assumption that can go wrong. It is instead the assumption that the isotopes were being generated and deposited at the same rates way back then. This does depend on environmental factors.
Some relevant parts:
> After all, fossilization on land is very rare; the water and wet sediments of the paleolake must have offered just the right protection from oxygen to preserve the bone.
> One possibility is that, at the time, it wasn’t a desert. While the Nefud is all sand and rock today, at the time of the Al Wusta fossil, the region was a savannah, covered in lakes and rivers thanks to summer monsoons. The multitude of animal bones found in the same location, from wild cattle to antelopes, suggest that game was plentiful. The lake itself lasted year round and offered a source of fresh water, though it may have come with risks as well as rewards: many of the faunal bones bore marks of carnivores’ teeth.
------
"But researchers behind the recent Misliya discovery argue that the bone’s location on the surface rather than in the lake deposits below mean it might not correspond to that climactic period."
Yes.
> What’s to say that the hot desert sun and strange weather patterns, radiation or whatever couldn’t skew the dating
Lots. For a start - only one of those would possibly affect the outcome of testing and would also be detectable.
> It seems further unlikely that such a bone from, 85k y/ago as they say, would be so close to the surface
Your incredulity doesn't affect the outcome one way or another and unless you want to dispute the fact that artifacts that are much older are often found on or close to the surface it's not based in any way to the real world.
> In mechanical engineering we don’t ever “trust” the calculations until they are thoroughly validated
And neither does the science around these dating techniques. In fact they're usually better supported than any engineering is.
> It seems backwards to hinge all our science on it when (AFAICT) it hasn’t even been validated itself!
And here's the thing: You're incredibly misinformed and that's why it makes no sense to you.
Given that the results of most if not all engineering can be directly tested, this seems unlikely.
I don’t care who supports what in engineering. If you put a dozen [gauges, potentiometers, accelerometers] on a truck and drive it for 1,000,000km varying conditions and the data matches up with the cross derivation for each instruments relation to the other, it is no longer a case of “who supports” -> it is either _fact_ or not and completely indisputable.
But it doesn’t become “supported” data for dropping said truck out of a plane. That’s lunacy - a dozen things not accounted-for in the normal model will occur.
Our models might hold for a few thousand years, maybe even 10k .. but how many times have we dated an >20k year artifact under varying conditions and been able to validate it without relying on another model?
Or as they would say about FEA, crap in, crap out (even though multiple models may agree, none are validated in such a method).
Not really. You're all over the place. I don't know why you think engineering is some kind of special branch that is not susceptible to the model breaking down even after repeated testing? Products of engineering fail all the time. Was it "bad engineering" or is "engineering bad"?
All of engineering lives up the abstract tree where you can "take things for granted" about materials, their properties and the repeatability of operation and use of things like transistors, resistors, tensile strength of beams, elasticity properties, etc. "Good engineering" takes into account tolerances and failure points. So then why do products built on these assumptions fail in the field all the time? Because engineering models are built upon assumptions that fail. You then incorporate these failure modes and get better at it. Just like everyone else.
>Our models might hold for a few thousand years, maybe even 10k .. but how many times have we dated an >20k year artifact under varying conditions and been able to validate it without relying on another model?
Because once something is validated and established, people don't waste their time re-testing it unless there is a specific reason to. Can you give a specific reason why it should be retested? What data have you produced that doesn't fit in the model? Or what changes in the model do you propose so that the new model best explains the current data? Or do you want to scrap everything? What is your reasoning?
For someone who has no expertise in the field, its rather odd you seek to cast doubt on something you don't understand, rather than asking a question that will inform your understanding.
For instance, when you dig something out if the ground, you can get a rough idea of how old it is just by looking at the layers of rock and material above and below it. We know something about how fast these layers can be deposited, and usually stuff further down is older (not always, but if the layering is disturbed there's often evidence of it). So if you find that your dating method makes no sense for objects with an obvious date range (based on where you find them) then your dating method is probably broken.
Obviously then if you take a leap over to objects that you find that you can only date in one way, you are taking a leap of faith. But in a few years, dating methods will come along that might let you test it in a different way entirely and either corroborate your first date or contradict it.
So I guess the question is what measurements are completely and absolutely independent? I don't recall in strata aging if the formation rate was alone used to determine age - so far as I recall the ages were dated by cross referencing known 'benchmarks', but then you've just created this very effect by assuming the age and then using that calibrate your method.
And for what it's worth, I am not suggesting that the dating or other methods are incorrect here. Just pointing out some possible issues in this logic.
Virtually every area of science has contributed to the modern understanding of dating. If something is fundamentally wrong in that understanding, it would be exciting to put it mildly.
And yes, there are issues as well. I could go on for hours about them. But archaeology is both an old field and a highly self-critical one. Any idea that's survived awhile is probably either "close", wrong in some very subtle ways, or extraordinarily attractive to our particular, western academia.
My teachers never pretended that quantum physics was a fully understood, concrete field. A lot of what they said was prefixed with "we don't really know if this is how it works, but this is the model".
No, they apply (or, rather, are reasonable approximations) in the specific case of objects that aren't too small, and that don't move too fast relative to each other, etc. That is, the common case, but not the general one.
We’re talking about archaeology, which is notably unconcerned with black holes or anything with a detectable de Broglie wavelength. I think that if were not going to be pedantic, and accept that we’re talking about physics as applied to Classical objects like finger bones, he’s right and there is little debate to be had. It we want to be a little pedantic we can say that QM is just about the best tested theory ever, and the rounding error left to quibble over isn’t a factor here.
If we want to be super pedantic we can point out that the “common” case on the scale of the universe is ultimately quantum-gravitational and therefore subject to physics that is not understood. Of course that majority is at distance scales we can’t access, or at energies or seem since the first second after the Big Bang. In that very very pedantic case you’re just as wrong as he is, but I think you’d rightly argue that it’s a pointless distinction in context. I’d agree with you.
[1] Standard physics isn't really up for question. Newtons Laws still apply in the general case.
All science is up for question, stuff that isn't questionable isn't science.
What you state reminds me of the scientists in the 1900s saying all science had been discovered.
If you haven't already, you should read Asimov's essay: The Relativity of Wrong (http://chem.tufts.edu/answersinscience/relativityofwrong.htm)
The sentiment you are expressing is very tempting, but it doesn't give credit to the knowledge we have actually acquired.
It's difficult to discern between the many levels of partial knowledge (as all knowledge is partial), but it's what we must do.
Direct, completely unmediated observation is not the only way to acquire knowledge. It is definitely a very good method. However, we humans are also incredibly good at finding clever, credible ways of inferring things from indirect clues.
Even inside human history, we make various guesses about when various events take place. The extant records that we use to date any particular item or event lead us, in many cases, to a best guess. How accurate this guess is - well, who really knows.
Quite often, there is conflict over when or even if certain events have occurred in the past. This is the nature of the lack of easily obtained records of the past. Even when there is extent documentation available, there is still conflict.
I take all the prognostications of dates in the far past as a guess, since we don't really know.
> However, we humans are also incredibly good at finding clever, credible ways of inferring things from indirect clues.
We are not as clever or even credible in a lot of what we do as humans. We are far too biased and political even in the fields of science and technology. That is just a part of our nature. If you looked at all the controversies over the last, what, 300 years, or we could look back over the last 2500 years and we'll see this rear its head many, many times.
I have stated the position that we should not be concerned that we are certain, but put in the efforts to keep investigating all areas for insight and further knowledge. It really doesn't matter if our models are incomplete and wrong as long as we keep moving forward. It's when we are certain that we lose the ability to move forward. In many areas in science (even in technology) we have become "certain" that our theories and models are correct. This is a problem and we need to address this.
[1] http://discovermagazine.com/2016/jul-aug/scientific-dating-m...
> The uranium-thorium method is often helpful for dating finds in the 40,000- to 500,000-year-old range, too old for radiocarbon but too young for K-Ar or Ar-Ar.
But I am by no means what you might classify as qualified or moderately familiar in this field.
Also it seemed to rely a lot on calibrating to the "known" date of ancient egyptian artifacts, which were in turn originally dated using the bible. Ie, if a radioisotope date from an artifact with a "known" date disagreed with that, it would be rejected.
I remember this guy being an important player: https://en.wikipedia.org/wiki/Joseph_Justus_Scaliger
Maybe I am just remembering it wrong or didn't look hard enough...
From what you wrote, it's both.
Since you seem to know a lot about it, can you pick one artifact (I don't think it should matter much which one) and outline all the data available for it?
Like... really basic research would get you further along in your studies. I see what you mean by “didn’t look hard enough”.
Please start there, I think you’ll see see more detail than I could hope to provide in one HN comment.
For a given date given based on dendrochronology I wanted to know who collected the samples, how many were collected, which were included in the final dataset (why and why not), the software used to align the rings with other dendrochronologies, get to see those samples that were rejected, etc.
The scientists in the featured article used a number of dating methods and the article specifically mentions Uranium–thorium Dating. Either way - the whole point of most of the quotes from the team is that they are verifying the data (and collection, and results, and so on) and aren't sure yet.
What you're describing is called "peer review" and any results will certainly include most - if not all - of the information you ask for.
Your Wikipedia link does not say anything like what you are stating.
You can have a series of cold summers with no growth or warm winters with continuous growth. Either can lead to many years -> 1 ring. Or you can have multiple warm/cold periods in one year in which case you can have 1 year -> many rings.
As a result the samples that are used for dating need to be carefully chosen, and this has not been done independently of the other sources of data.
I also remember it was difficult to find the raw tree ring data (all the images they tried). What was available was only some final data on ring widths, this made me question their assessment that alignments of the various tree ring datasets could just be due to chance similarities.
Perhaps start here: http://web.utk.edu/~grissino/itrdb.htm
Deposits. Regular, periodic deposits.
>"the consistency of Nile River flooding meant their calendars are likely the most accurate"
You seem to be talking about something different now.
>"the consistency of Nile River flooding meant their calendars are likely the most accurate"
You seem to be talking about something different.
Yes the dating techniques are verified by corroborating it with a lot of other evidence such as tree rings as well as other dating methods, it's also well corroborated with entirely different fields like geology, history and physics.
As for being close to the surface, there are quite a few geological process that can come into play. There are places on earth that have fossils hundreds of millions of years old on the surface. This is not in any way remarkable.
> So I suppose a similar thing applies here in dating science, except, it’s impossible to validate for another thousand centuries
This sounds alarmingly like an argument you'd get out of Ken Ham. Are you a creationist that has trouble accepting an earth older than 6000 years? The debating style of asking seemingly probing yet actually well understood questions screams creationist (and climate change denialist) as well. You also fit the profile of creationist and climate change deniers, engineers that think they're smarter than the actually are and don't know what they don't know.
As for finds like this, despite the headline it's completely unremarkable and fits easily within what we know of human migrations: https://en.wikipedia.org/wiki/File:Human_migration_out_of_Af...
I see no evidence that you are responding in good faith to any flaws in your reasoning, you're continuing to make an argument from incredulity. So I'm sorry if you're not a creationist (not as sorry as I'd be if you were), but when you look like a duck, argue like a duck and respond like a duck I start getting that duck vibe.
How about you respond to the points in your post:
> Not to be that guy, but I’m really starting to question the accuracy of dating techniques when they publish finds like this.
Why when they publish finds like this? There is nothing extraordinary about these finds, they sit comfortably inside what we know of human migrations.
> This finding is only significant because of the age, but have we ever verified our dating techniques over 5k years? 10k years?
You're arguing against archaeology, geology, history and nuclear physics here. Do you think all these branches of science are being dishonest?
> It seems further unlikely that such a bone from, 85k y/ago as they say, would be so close to the surface.
Why do you find this surprising? There a quite a few geological process that can result in this. Nearly all fossils we find are quite close to the surface.
> The discovery is “a dream come true, because it supports arguments that our teams have been making for more than 10 years,”
Ten years of debate could be motive enough for some people to fabricate the finding.
EDIT: All that aside, assuming it is legitimate and we can trust the discovery, I definitely agree an absolutely phenomenal discovery
Andrew Wakefield: https://en.wikipedia.org/wiki/MMR_vaccine_controversy
That being said, it is extremely improbable.
I wonder how you can test that a fossil wasn't just discovered elsewhere and moved to a convenient place, if the ground composition is sufficiently similar
For instance, carbon dating and analysing the ethnic origins of the skeleton could lead you to say that you have an Australian (Australoid) fossil from 20,000 years ago.
If you found that in Northern America that would raise serious questions about where exactly it was found and if it was moved since it doesn't fit within any of our current understandings of migration patterns.
"Groucutt and the rest of the team used a number of dating methods to confirm the likely age of the Al Wusta finger. For the finger itself and the tooth of an ancient hippopotamus found nearby, they applied U-series dating. Like radiocarbon dating, the method works by looking at radioactive decay in the preserved materials. The age of the sediments around the bones was calculated using optically stimulated luminescence—a technique that reveals the last time rocks and sand were exposed to sunlight."
If dropped by a human, then that would still be evidence of the presence of humans.
Unless you're suggesting that the bird or human buried the finger in the soil without creating any signs of the soil having been disturbed.
"as a joke"
Religious rituals are just as likely, as well as being deposited with ani al droppings after becoming an unfortunate snack for some scavenger or carnivore. Also flood runoff, why not?