Ancient Egyptian Mysteries

Researchers using the Large Hadron Collider at CERN say they’ve recently discovered a new exotic form of subatomic particles called tetraquarks. They exist for just fractions of a second, so they’re hard to spot and study. But, luckily, University of Cambridge physicist Harry Cliff, is working on the experiment that discovered them, as he described to Chris Smith...

Harry - Very simply a tetraquark is a particle made of two quarks and two antiquarks. So, sort of four objects inside it basically, hence the tetra. It probably requires a bit of unpacking though, because well, you might ask what's a quark? Well, every atom has a nucleus, and you probably know that the nucleus is made of protons and neutrons. And we've known for more than half a century now, that protons and neutrons are made of three quarks each, bound together. Until recently we only knew of combinations of quarks that came in threes, or in pairs. So tetraquarks are a whole new class of particle that we didn't know about until relatively recently.

Chris - It's funny, isn't it? Because the reason we call atoms atoms, is the Greek word tomos means cut. And atomos means can't be cut down further. So initially scientists thought atoms were the smallest possible things. And then people realised that atoms have got things inside them, protons and neutrons, and thought they were the smallest things. And then people like you started smashing things together at very high energies and realised that those tiny things inside atoms, have actually got tiny things inside those. Those are the quarks.

Harry - Yeah, that's exactly right. And there was this big mystery in the 1940s and 1950s, when in particle colliders and in astrophysics experiments, people were discovering all these new subatomic particles, with all strange names. They're all usually, with Greek letters, like omegas and deltas and lambdas, and it was called the Particle Zoo. No one really understood what these particles were, and it was eventually realised you could explain this huge number of different particles, as being combinations of basically six different types of even smaller particles called quarks. So that's our most up-to-date understanding of the basic ingredients of matter today.

Chris - Why don't these things hang around for very long though?

Harry - Basically it's to do with the forces that bind them together. So actually there's only one particle made of quarks, as far as we know, that's completely stable and that's the proton. So that's the thing that's inside every atom. And that is a good thing that the proton's stable because if it wasn't, well, you know, every atom would disintegrate. But anything apart from the proton basically is unstable. It can always collapse, and it can either sort of break apart, or annihilate with itself and turn into other particles. So these things, because they're bound together, but not in a way that allows them to exist for any length of time. And they very quickly disintegrate into other sets of particles, which we then detect in our experiments.

Chris - Are they therefore a real and important part of physics? Or do you think they're just an artifact of the fact that you have, in an unnatural way, slammed particles together? You can detect these things transiently, but because they disappear, they play no part in genuine physics, or do you think they really do have a role to play in the way that the universe works?

Harry - Well, they tell us something about one of the four forces of nature. So we know about four forces, gravity, the electromagnetic force, something called the weak force, and the strong force. And the strong force is the force that holds the nucleus together, holds quarks together. But the strong force is really mysterious. Despite being, you know, a force we've known about for ages. It's really hard to understand, and it's very hard to make predictions using our theory of the strong force. So we can't really work out in advance, how quarks come together, and what combinations are allowed and which ones aren't allowed. So discovering new particles like these tetraquarks tells us something about the way this strong force interacts, and as one of the four basic forces in nature, that's a really important thing to get a deeper understanding of, and has impacts on the rest of our understanding of particle physics as well.

A new video game simulation is being published by a company called Slug Disco. It models the evolution of life in a realistic underwater world. You put basic starting creatures into the water, and then create the environment in which they will live. You then watch as they evolve and adapt to their environment, and to each other, just as Darwin described. It’s called Ecosystem, and the Naked Gaming Podcast’s Chris Berrow caught up with its creator, Tom Johnson...

Tom - It's kind of inspired by some research that was done in the nineties at MIT, by a guy named Karl Sims, and he was working with virtual evolution. So the idea is that you have these creatures that are actually a bunch of boxes joined together, basically. And they have virtual brains that are basically pipeline computers. So they take in visual input, auditory input, stuff like that. They do a bunch of processes. And then as an output, they apply torques at all their various joints. So they kind of move around just like we do. So unlike a normal game, the creatures aren't necessarily playing like an animation that an artist made, they're actually contracting joints at each joint that they have. And so the idea is that if you take a bunch of these creatures, just like totally random ones, with random brains and random bodies, and you throw them in the ocean, most of them will just kind of flail around, right. They'll just be moving their hands and arms, or their limbs, and not going anywhere, but a few will probably get a little bit. And if you let the ones that move the furthest have the most children, then after enough generations, you will actually have creatures that can actually swim. So in that sense, it's like a true evolution game, because the physiology is driven by the function. And so the premise of the game is basically that you shaped this environment and then, you sort of throw in these creatures and they adapt to all the different niches that you create

Chris B - How do you model something like that? Because I know that there are existing models for evolution, but how did you actually design that into a game context? Because that strikes me as probably the most difficult thing.

Tom - Yeah. It took a lot of work. And in fact, when I first started, it would actually take a full day just to get an evolution, just to get a creature that can kind of swim. It was a very sort of experimental process, because it doesn't map quite cleanly to an existing game. There's not some well-established tradition that I could kind of follow in, and copy, you know? So to some extent there's a big element of creativity to it, that you kind of have this fish tank, except that the fish are morphing to your tank.

Chris B - What are some of the other factors that are at play here?

Tom - There's a couple of other ones. One that I did recently was a creature vision system. So in addition to their physical body shape, their skin colouration and pattern, and stuff like that also evolves. And it's sort of encoded in their DNA. And so when creatures are preying on each other, they have a vision simulation. So in order to actually see a creature, if it's green against the green background, it's harder to make that out. Like the better it fits to that, the harder that creature is to see, because for example, a bunch of foragers that have no predators anywhere don't actually really need camouflage. And so they may end up more like the, you know, the birds of paradise, right? Like the classic ones with the incredibly ornate, because it's better for mating, right? If you have the best shiniest, whereas if there's a bunch of huge sharks swimming around looking for you, then suddenly you don't want to be the most ornate, beautiful purple fish, but you want to be the one that looks just like the dirt.

Chris B - I'm presuming that if you were to in real life, create an environment, that exactly the same thing wouldn't happen every time. Like, you know, you might suddenly find that actually, you know, some creatures with shiny wings or whatever would start to become very prominent. But then if you ran it again in real life, you might find that actually camouflage became the way to go just for no reason, just because that's sometimes what happens with evolution. Does that happen in the game as well? Or is it very much if you were to chuck the same thing in the same environment, it happens the same way.

Tom - There's quite a bit of variation, just because of random features and even how creatures are reacting as part of their environment is the other creatures, in a sense. There's a decent chance, at least if you set the pressures just right, that you could probably get a camouflage to statistically occur more frequently. One of the main goals for the game was that I wanted to sort of make sure that it could actually reproduce, as much as I could, the amount of variety that you see in life. So I think I would have been a little disappointed if like, you always got the same handful of things. And for that reason, they often tend to come out looking like little monsters. You get a lot of very alien looking things. But there's probably a decent chance that if you threw some microbes into the ocean and Earth, you may not necessarily get fish again. You know, you might not get things that look exactly like the fish that we're used to.

The first of the mysteries we’re going to look at are the pharaohs - the Kings and Queens of Egypt. We have reasonably good chronological records for the later periods of ancient Egypt, but, as you go back further, the records get more murky. This is made worse by the fact that new pharaohs had a habit of making their mark by demolishing the paintings and monuments of their predecessors. Tom Higham is an archaeological scientist at the University of Oxford and author of the new book ‘The World Before Us: How Science is Revealing a New Story of Our Human Origins’. He’s been involved in a project to figure this out...

Tom - Yes, absolutely. What we see quite often is that new pharaohs came to power by virtue of plotting or coups, and they overthrew their predecessors. And once they'd done that, in an attempt to establish their own legitimacy, they would go back and rub out evidence for their predecessors in the form of temple inscriptions, papyri, and so on. And in fact we see this to this day: Hosni Mubarak's image - and that of his wife - was systematically removed by court order in Cairo following the Arab spring. So it's something that we see again and again.

Chris - And this presumably creates something of a puzzle, because although they wrote things down and we knew who lived when in relation to whom, if we haven't got physical things to tether to particular eras or people, it makes actually understanding that timeline that much more difficult!

Tom - Indeed. And this is part of the problem. I mean, we often think about ancient Egyptian chronologies as being absolutely precise and robust. But as you say, there are gaps in the record, and there are periods where pharaohs tried to rewrite history for themselves and eliminate the evidence for other people. And when you visit Egypt and you see the walls of temples and so on, you can see where, often, there has been destruction, and people have subsequently pecked out evidence for cartouches identifying different rulers and pharaohs. So as you go back in time, we have problems identifying precisely who ruled when, and for how long.

Chris - How are you trying to get underneath this then, and basically write history the right way, rather than the wrong way that people have sought to manipulate the record?

Tom - One thing that we can do is we can use radiocarbon dating. And radiocarbon is a method that was developed in the late 1940s, so it's a long established tool, and it basically revolves around the fact that all of the carbon that we and all living organisms uptake has a tiny proportion of radioactive carbon, or carbon-14. And this radioactive carbon is constantly replenished until death. When an organism dies, the amount of radiocarbon slowly begins to degrade away and disappear. And what we know is the rate at which that disappearance occurs: we know that every five and a half thousand years, half of the amount of radiocarbon disappears. And so by measuring the remaining radiocarbon in an archaeological bone or piece of wood, we can get a date for it.

Chris - But people must've done that; given this technique is coming up for its hundredth birthday, as you're saying, they must've already done that with all the artefacts we have from ancient Egypt.

Tom - Yeah, they did. But what we found was that there was a sort of mistrust of radiocarbon methods, because it hadn't properly been applied in the past. Instead, people had just dated anything really; they dated old pieces of charcoal and wood from temple complexes, which often predated the use of that wood in those complexes of temples, and graves, and so on. And this is a really key point in radiocarbon: we have to select good material that date as closely as we can to the date of the archaeological event we seek to understand.

Chris - I see. So if, for instance, I wanted to know how old my wheelbarrow was, but I inherited it from my granddad, I would get a false date because it's not a new wheelbarrow. Whereas if you go for something which can't be inherited, or can't be recycled, as it were, you potentially have got a much more fine grained - if you'll excuse the pun, because I was thinking of things like cereal grains and things...

Tom - Absolutely. So what we did was we went back to these burial contexts that contained independent historical evidence from the Egyptian chronology. So for example, we found evidence in the form of inscriptions on the side of the grave, in which that person died during the seventh year of the reign of King Joseph, for example. And then in that grave, we would find short-lived pieces of grain, and floral wreaths in the form of funerary materials, and so on. Those are the things we focused on dating in order to kind of crack the problem of when these things happen in the past.

Chris - That would give you a nice, neat timeline for that murky period back in history. When you assembled that timeline, did you then discover that in fact, things that we thought we understood well were in fact wrong, and we had it wrong all along?

Tom - We didn't find that in the recent period, because of the fact that we have a pretty good understanding of that historical record. So we didn't find major differences there; in fact, that was one of the things that gave us confidence that we were getting things right. But as we moved back through time, back through the Middle Kingdom and especially into the Old Kingdom, we found that our date estimates were much earlier than we thought previously. And they were about a century earlier than previous estimates had put forward. So that was quite an important conclusion to reach. Also, we found that the period before the domestic periods - the period of the Egyptian state and its formation - we found that this happened much more quickly than had happened in similar cases of state formation in places like the Middle East and Africa. And so that was also a very interesting thing, because it showed that the Egyptian state began very quickly, from pastoralists and people that were moving around the landscape, from a period where they then started to grow crops and to be more sedentary, and live in the same place. And shortly after that, state formation happened and we get pharaohs, we get institutions, we get writing, and so on and so forth.

One of the mysteries concerns a long lost city, called Punt, which was hugely significant as a trading partner of the ancient Egyptian civilisation. Unfortunately, while they wrote a lot about Punt, the Egyptians didn’t say exactly where it was, so archaeologists have hit a dead end trying to understand how that ancient trade operated. Now, that might be about to change thanks to a breakthrough involving animals that the Egyptians kept as pets and went to Punt specially to purchase - baboons! They also mummified them, meaning specimens of those pet baboons exist in museums and, critically, still carry a chemical fingerprint of where they came from originally, putting Dartmouth College’s Nate Dominy on the scent of where Punt might have been, as he told Chris Smith..

Nate - There are two mysteries, a mystery wrapped in a mystery. And the first involves baboons because baboons have a very large distribution across Subsaharan Africa. And generally across Africa, baboons are disliked. You rarely see baboons in any kind of statuary or carving or any kind of handicraft. Egypt, however, is the big exception because when you look at the entire arc of Egyptian history, you see that baboons have been revered, they've even been deified. They've been elevated into the Pantheon of Egyptian gods. So it's really quite a striking reversal to the general patterns across Subsaharan Africa. The puzzle for someone like me, who studies primates, is that baboons never lived in Egypt. The Holocene fossil record, which is the period of time of modern human habitation and agriculture and complex societies, is entirely devoid of any evidence of any primate whatsoever - let alone baboons.

Chris - Have we got physical specimens of baboons from that geography nevertheless? They must have encountered them because they defied them.

Nate - That's right. So we find baboons buried in human contexts. They were deliberately buried. The oldest evidence looks like it might've been a zoo. One young baboons is buried with a young person about age 12 or 13, suggesting status as a pet. And then at later periods, we get Royal mummification where the animals were actually wrapped in linens and interred in Royal tombs in the Valley of the Kings. And then in a still later period, during the Roman and Greek period, we get the period of animal cults where baboons and many other animals were mummified on a practically industrial scale. You get tens of thousands of animals being mummified during that period.

Chris - So therefore if you've got evidence of these animals being deified in that particular geography, you've got evidence of specimens of them being brought to that geography, but there's no evidence that they were naturally there, this argues that any baboons that are there were brought there by human activity and therefore the question must be from where?

Nate - Precisely. And the Egyptians, they have written records of importing baboons into Egypt. They have paintings and reliefs on their temple walls and tombs showing the importation of baboons from a distant place. And they tell us that place - the place was Punt. And that's the other mystery is, where was Punt?

Chris - So there's lots of references to a place, but that place no longer exists, and we don't know where it is?

Nate - Right. Historians have argued about Punt because it was terribly important because the Egyptians, typically when they wanted resources, they might go to war to get those resources. We know the Egyptians went to war with the Nubians, they went to war with the Hittites. But with the Puntites, they sent emissaries, they sent ambassadors, they sent diplomats. This was a very important trading partner for the ancient Egyptians, primarily because the Puntites produced very valuable incense that the Egyptians used for religious purposes. So the Egyptians were highly motivated to travel great distances to go to Punt for these exotic luxury goods, including baboons.

Chris - So how can you use our knowledge of baboons to work out where Punt is then?

Nate - Baboons are a really great animal system for this question because baboons drink water every day. And the water in your environment reflects the rainfall, and the chemical composition of water evaporates at different rates. And so when animals are drinking water on the landscape, they incorporate those chemical signatures, the oxygen stable isotopes in the water, and that incorporates into their bones and in their teeth and in their hair. And so you get this geographic fingerprint of where an animal has been living based on the kind of water and food it's been ingesting.

Chris - But what about if you do what you said, which is that there's evidence that there were animals being held in captivity in Egypt, will you not then see the signature of Egypt rather than the signature of where the animal came from written into those ratios?

Nate - Yes, that was a great risk of the project, that long-term captivity would produce a geographic signature associated with living in captivity in Egypt. And so we use different tissues, hair, bone teeth, which integrate drinking water and food over different intervals of the animal's life, and a large number of animals. For example, the baboons that we studied that were at the Petrie Museum in London, those animals uniformly showed us a signature that was consistent with a lifetime living in Egypt. And so we think the Egyptians may have had a husbandry program, they may have been breeding them in captivity. But we got very lucky - there was one animal at the British Museum that showed us a signature in the teeth that showed a distinctly foreign signature. It was unambiguously non-Egyptian.

Chris - So in order to work out where Punt must have been, are you reasoning then that if you triangulate the origins as written down in the teeth and other specimens of these baboons, that Punt must be somewhere relatively equidistant from these places, or close to where a lot of these animals were originating from, that that would give you a narrowed geography for where Punt was likely to be?

Nate - Exactly. So the Egyptians tell us that Punt was East and South of Egypt, and they tell us that you could reach it by land or sea. Problem is that East and South of Egypt - still a lot of open possibilities! And so what we can do is we can take baboons living in all of those competing areas - Somalia, Eritrea, Ethiopia, Yemen, Sudan, Uganda - we can take that baboons living in those areas now, and we can look at their chemical signatures and create a chemical map, if you will, of that region. And so then we can match the mummified specimens that are present at the British Museum to populations in those areas. And the great thing about our analysis is we could definitively rule out some places, and we showed a very strong match to animals living in Eritrea and Somalia today.

Chris - That would be, therefore, the most likely place where the animals were sourced from, but do not just think that it could just be that was a good hunting ground, and they were transported from there to wherever Punt was?

Nate - That's right. Punt was both a kingdom and an emporium on the coast. So there was a market town or port. And so we think the Egyptians would have pulled their ships up to the port and they may have purchased or traded for animals that were there in the port city. But the animals may have been sourced from farther inland, and that makes sense. We think the Puntites knew their market, they knew their consumers. And so they would have gathered animals from farther inland and brought them for trade with the Egyptians.

Chris - So how much narrower is the search for Punt now in the wake of what you've done?

Nate - Much narrower. For 150 years, scholars have been debating about the possibility of the Arabian peninsula. So Yemen has always been a strong contender for the location of Punt. Some authors have put it in Mozambique or Uganda. We can rule those places out. And we can say definitively that it was somewhere in Africa, on the horn of Africa, probably in Eritrea and Somalia. We can't distinguish between those two places, which are the two contending places that most scholars agree on.

Chris - And is there any way to nail it well and truly?

Nate - Yes, I think so. I think if we can turn to ancient DNA, maybe turn to some of the other tissues that were coming out of Punt, if they all start to point in the same place and corroborate each other, then we'll really have something. And obviously archeology is where we need to go. It'd be nice to dig in some of those areas. And if we can find the remains of these ancient places that'd be the clincher.