Two thousand years ago, a  Roman merchant ship was sailing across the Mediterranean Sea  when something went wrong.

Just off the western coast of Sardinia,  the boat sank beneath the waves, condemning its sailors and cargo to the sea floor. Onboard were plenty of clay jars,  dishes, and other artifacts.

Maybe a Roman ghost or two. But the ship’s real prize was  more than 30 metric tons of lead that had been processed into a thousand ingots. And while the ingots’ original  destination has been lost to history, their story was far from over.

These bars were destined to  serve a purpose far greater than anyone in the Roman  republic could ever conceive. Without the loss of that cargo,  we’d be unable to run an experiment that hopes to answer fundamental  questions about reality. Because in the 21st century, that  shipment of ancient Roman lead is protecting the coldest cubic  meter in the known universe.

A cubic meter where scientists are hunting for what might be the rarest  event in particle physics. If they find what they’re looking for,  we might finally understand the outcome of a cosmic war that ended 13.7 billion years ago. This is a very weird, but true story  of two different fields of science, archaeology and cosmology, colliding.

I’m here to tell you how this ancient  Roman shipwreck could help explain why you, and I, and everything else  in the universe are here at all. [♪ INTRO] Our story begins just a bit after  the Roman Empire crumbled to pieces, when neon legwarmers were in  fashion and Who Framed Roger Rabbit was the highest grossing film at  the North American box office. People loved that movie! It was 1988, and about 10  kilometers off the Sardinian coast, scuba divers were investigating the sea floor, searching for shipwrecks and the  artifacts that they might contain.

In doing so, they stumbled  upon an ancient treasure. Twenty eight meters beneath the waves,  hidden among the sand and seaweed, they spotted the unmistakable outline of a ship. And from the looks of the clay jars  on board, it was Roman in origin.

Now, Roman shipwrecks are actually pretty  common throughout the Mediterranean. At their height, both the democratic  Roman Republic and the subsequent Roman Empire dominated the sea’s  European and African shores. They laid claim to every harbor  from Gibraltar to Turkey.

And when you’re that big,  you’re gonna lose a few boats. This particular shipwreck  was found two kilometers east of a tiny island called Mal Di Ventre. Which might amuse some of you  Italian speakers out there, because it translates to “stomachache”.

But that’s actually a likely mistranslation from the original Sardinian  name, meaning “bad winds”. Which may contribute to  stomachaches…and also to shipwrecks. For more information, though,  archaeologists needed to take both a figurative and a literal plunge.

And that is when things  started to get interesting. After 2000 years, the sea had destroyed  much of the ship’s perishable parts, including most of its original wooden structure. But around 10 meters of the keel had  been buried below the sandy seabed.

And plenty of erosion-resistant metal  and stoneware had survived as well. From these pieces, investigators could tell  that the ship was much bigger, and much beefier than most of the others that  had been found around the Mediterranean. It was a Navis oneraria magna, a  class of sail-driven merchant ships that measured about 30 meters  long and 9 meters wide.

For comparison, that’s about the same size as nine school buses parked in a 3-by-3 grid. It was huge. At one end of the wreck, archeologists found items that the crew likely used during their journey.

There were jars used for storing  food, as well as water and wine. There was also a millstone,  which the vessel’s sailors would have used to grind their own  grain in the middle of a voyage. But in the center of the wreck, there  was an even more remarkable find.

The ship’s cargo included a thousand lead ingots, stacked as neatly as they would  have been two millennia ago. Each of these ingots was  roughly trapezoidal in shape, measuring 45 centimeters in length and  10 centimeters in height and width. In other words, like, roughly the size  of your hand and forearm together.

But because lead is so dense, these  metal blocks were 33 kilograms a pop… or about the weight of a ten-year-old child! Or, like, a German Shepherd. Or, like, 1/50th of a Kia Sorento.

So with more than a thousand of these  ingots on board, this ship was lugging around a shipment of lead that  weighed over 33 metric tons. And that explained why the wooden hull  had been strengthened in some places with nails up to 80 centimeters long! Now, to an Ancient Roman,  lead was kind of a big deal.

Along with their Greek neighbors, they  mined and smelted so much of the stuff that evidence of this industry can be  found as a layer of pollution in ice cores thousands of kilometers away in Greenland. It was actually one of the first metals  that humans learned to extract from an ore. In this case, a mineral called galena.

And it has a lot of properties that make  it worth figuring out how to extract it. Lead is soft and easy to work with. But at the same time, it’s durable  and doesn’t corrode easily.

Plus, galena is also full of  silver, which has its own uses. So even if you’re trying to mine for  silver, you end up with lead as a byproduct. Bonus!

In fact, Rome had such easy and abundant  access to lead that at one point, policymakers had to step in and  restrict how much was being produced. But despite that abundance, before  the Mal di Ventre discovery, archaeologists had only managed  to find a few lead ingots on shipwrecks scattered around the Mediterranean. So this find instantly became  the biggest load of ingots ever recovered from the ancient world.

Professor Donatella Salvi, one of the lead  archaeologists who investigated the wreck, told us in an interview that the discovery  was of huge importance to Roman studies. By studying the unique  construction of this merchant ship, which had been specialized  for carrying such heavy loads, we can learn a lot about Roman engineering. But what about the lead itself?

Unfortunately, we cannot know for sure exactly what the Romans had planned  for this particular shipment. The metal’s physical properties made it  useful in a wide variety of products: coins, anchors, and slingshot  ammunition, to name a few. Romans even used lead to line their  aqueducts, and build a network of water pipes that brought a reliable source of  water to an enormous territory.

That probably made the water somewhat  toxic sometimes, but give them a break! It was 2,000 years ago! And we were using lead in water  pipes not that long ago ourselves.

We might not know what these  ingots were destined to become, but there is something we do  know just by looking at them. Each one bears an inscription  stamped on the top of it. And while the text might seem, to us,  to be a nonsensical string of letters, it is actually telling us who cast it.

For example, this one is shorthand for  the Societas Marci et Caio Pontillienorum. In other words, it was made by  a company owned by two Romans named Marcus and Gaius Pontinelius. Their company produced the majority  of the ingots in this shipment.

Over 700 of them! And a subset of those ingots are  also stamped with the letters PILIP, which researchers believe is a tribute  to a deceased servant called Phillipus. Meanwhile, there are a bunch of stamps corresponding to other men in  the lead manufacturing business.

Like Quinto Appio, and Planio Russino. Professor Salvi told us this is invaluable  information that paints a picture of both the entrepreneurs of the time, and the powerful families that were  involved in metal mining and trade. Together, these ingots tell us  about how the Roman Republic managed its mines within its territory…that  they were run by private individuals, as opposed to being directly run by the state.

The inscriptions also help us  narrow down exactly when this ship made its final journey, because the  names that the manufacturers use tell us that they identify as Roman citizens. That was only possible when urban Italian tribes got representation in the Roman Republic. We know when the law that granted them  that right was passed (it was 89 BCE), so we know the ship must have met  its fate some time after that.

And yet, there are still a lot of pieces  missing from this 2000-plus-year-old puzzle. Salvi says that archeologists don’t  know where this shipment was headed, whether a delivery of this size was  a one-off or a regular occurrence, and ultimately, what caused the ship to sink. But, because the ingots were still neatly  stacked on the remains of the hull, the ship must have sunk straight down.

And there didn’t seem to be any  major damage to the hull, either. So it’s possible that the region’s famously  ‘bad winds’ could have destabilized the heavy load, causing the ship to  take on water and dip beneath the waves. But some archeologists think  there is another possibility.

During the first century BCE, the  Roman Republic was in turmoil, with several civil wars  raging across the territory. I mean, throw a dart at a timeline and  you’re going to hit some Roman Turmoil. But things were particularly  bad during that period.

And it meant a lot of attacks on Roman boats. With such a gentle descent to the sea  floor, some researchers think that this merchant ship was deliberately sunk by its  crew, after something like a pirate attack, to stop an enemy from seizing  this extremely precious cargo. And if that’s the case, we  owe the crew of that ship our deep appreciation for their sacrifice.

Because nobody got their hands on that cargo until long after the fall of the Roman Empire. But it wasn’t just modern archaeologists  who wanted these ancient ingots. Researchers in a completely  unexpected field also did.

And those scientists hope to use them to solve one of the universe’s biggest mysteries. This SciShow video is supported by Babbel. Babbel is one of the top  language-learning apps in the world, with 14 different languages at your fingertips.

Including Italian, which  comes in handy for this video. With Babbel’s help, you wouldn’t  need us to translate Mal Di Ventre into stomachache, because  you’d know that already. Also, everything we learned  from Professor Donatella Salvi was sent to us in an email written in Italian!

So knowing multiple languages can come  in handy when you least expect it. You can learn through a wide  variety of lessons that prepare you to have practical conversations about  travel, business, relationships, and more. There are also several subscription  plans for you to choose from, including a lifetime subscription.

And I know a lifetime is a long commitment,  but you can cut that subscription short and get all of your money back in the first 20  days if you find out it’s not your thing. When you sign up using the link  in the description down below, you can get up to 60% off. According to our best theories of the early  universe, we shouldn’t actually exist.

And by “we” I don’t just mean you and me. I also mean the Earth, and the  Sun, and all of the other stars, and neon leg warmers, and Kia Sorentos,  and black holes, and neutron stars. Everything!

This mystery is, of course,  far older than any shipwreck. It all started shortly after  the beginning of time itself, when the universe was in its Jessica  Rabbit

Era: young and indescribably hot. The universe had expanded and cooled  just enough to let some of its energy transform into matter and  antimatter for the very first time. In an infinitesimally small amount of time, basically all of the stuff  that would ever exist was born. But there’s a problem.

Whenever a particle of matter  and its antimatter twin meet, they annihilate one another. In a literal flash of light, their  mass gets converted into energy, and rejoins the cosmic pool from whence it came. So if matter and antimatter  are produced in equal amounts, which is what the laws of physics tell us,  and they’re destroyed when pairs meet up, the total amount of matter and antimatter  in the universe should be… none.

But you may have noticed that’s not the case. Otherwise we wouldn't have hotdogs. From our observations of the universe, it appears the ratio of matter to  antimatter wasn’t exactly one-to-one.

It was more like one billion  and one to one billion. In other words, for every one billion  matter-antimatter pair annihilations that happened in our baby universe, there was  somehow one matter particle left over. And eventually, those leftover matter  particles came together to make every single star and planet and YouTuber  Author CEO Sock Salesman.

That’s me. But we don’t know how or why this happened. It’s one of the biggest outstanding  questions in particle physics right now.

And scientists think the answer could lie with some of the most elusive  subatomic particles of them all. They’re called neutrinos. You can think of them as cousins to a more recognizable subatomic  particle, the electron.

But unlike electrons, neutrinos  don’t have an electric charge. They’re also waaaaaay less massive, which is something because  electrons aren’t exactly hefty. Put these two facts together, and you get a unique group of particles that  almost never interact with other matter.

In fact, as you are watching this, trillions of neutrinos are streaming  through you without a single side effect. They can pass through an entire  planet as if it isn’t there. Now, that means that there’s  nothing for you or I to worry about, but scientists have to worry about  capturing them to learn how they work.

So despite physics predicting that  neutrinos existed about a century ago, we’re still lacking some pretty  basic information about them. Like, we still don’t know how much mass they have. So I can’t even tell you how  many Kia Sorentos they weigh.

We know it’s not nothing, but beyond  that it’s kind of anyone’s guess! Another big question is whether or not a  neutrino can act as its own antiparticle. Now this is where we’re going to get  a little more particle physics-y, so please stick with me!

According to the Standard  Model of Particle Physics, which is the theory that scientists rely  on to understand the subatomic world, every matter particle has its  own antimatter counterpart. For example, you’ve got protons and antiprotons. Electrons and antielectrons.

Each twin in a matter-antimatter  pair has the exact same mass, but the opposite charge. Neutrinos, though, are neutral, so does  that mean they don’t have antiparticles? NO!

Turns out, charge is just  one piece of the anti-puzzle. There are other properties  that I had never heard of… things like “Lepton Number” and “Helicity.” Offscreen: It’s helicity!

Hank: Oh, it’s helicity. And those are also opposite in anti-particles. So anti-neutrinos are very much a thing. In fact, don’t look now, but your body  is currently emitting antineutrinos!

No, really. Don’t look. You won’t be able to see them.

Weirder than that, though, back in  the 1930’s an Italian physicist named Ettore Majorana hypothesized that a  neutrino could act as its own antiparticle. Such dual-acting particles have come  to be known as Majorana particles. If scientists discover that neutrinos  truly are their own antiparticle, for reasons that get pretty  complicated pretty fast, it could explain why our  universe is filled with matter.

However, Majorana’s hypothesis was just that. A hypothesis. And he made it in the early  days of particle physics.

Although the field has made  a lot of strides since then, it has not made much progress on neutrinos. But we may finally be on the verge of  having proof that Majorana was right. Deep beneath the Apennine  mountains in central Italy, physicists created an experiment.

Its name was CUORE, which is Italian for heart. But of course it is also an acronym, short for Cryogenic Underground Observatory for Rare Events. And part of CUORE’s mission is  to observe a hypothetical event in particle physics called  neutrinoless double beta decay.

Basically, there are a few ways that  unstable atoms release particles on their way to becoming stable atoms. Most of these forms of radioactive  decay are garden variety and well understood by physics. But neutrinoless double beta decay?

Never been witnessed. And here’s where you’re gonna  have to trust us on two things because the science is … intense. First, neutrinoless double beta  decay would require neutrinos to be their own antiparticle.

And second, neutrinos being their own antiparticle could have led to the accumulation  of matter in the early universe. It is a multistep process. I’m told that it is very complicated.

Though if any of you out there are  craving an episode on leptogenesis, and right-handed neutrinos,  and the see-saw mechanism, there is an internal debate going on at  SciShow over whether we should cover it. So if you want to know, let  us know in the comments. But remember, neutrinoless double  beta decay itself is hypothetical.

It’s never been observed before,  which means if it does happen, it’s an extraordinarily rare process that needs an extraordinarily large and  sophisticated experiment to detect it. So before CUORE was able to get up and running, scientists had to start with some  early, scaled down proof of concepts. Basically you’d need a lump of  radioactive material, and a detector that is sensitive enough to spot when  antineutrinos are and are not present.

So starting in the 1980s, experiments  featured radioactive samples weighing just a few hundred grams. That’s just a few Costco hot dogs. And over the decades, this got  scaled up to over 700 kilograms inside the full-scale CUORE facility.

For the radioactive element, the  team went with Tellurium-130… not only because it undergoes  the kind of decay they needed, but because it does so with a  really clear energy signature that will shine a beacon on any missing neutrinos. But it isn’t one massive block of the stuff. Instead, CUORE houses nearly  1000 Rubik's cube-sized blocks of tellurium oxide crystals that have  been arranged into 19 neighboring towers.

There’s a lot of weird units in this video. If neutrinoless double beta  decay does happen, then… again, for very complex reasons… the surrounding tellurium oxide cubes would heat up by a very small  but very specific amount. And that is why each crystal has an extremely sensitive thermometer on the surface.

It’s also why each crystal needs to be kept at an incomprehensibly frigid temperature. And by incomprehensibly, I mean  it’s about 270 times colder than the depths of outer space! It is the coldest cubic  meter in the known universe.

Like, literally, if there is a colder spot  in the universe, it’s because aliens made it. But the technique we use to  create it is surprisingly simple. You know how when you get a cup  of coffee or like, a bowl of soup that is just scalding hot, and you cool  it down by blowing over the top of it?

Well, CUORE kinda does the exact same  thing, except it isn’t blowing air over the thing it’s trying to cool  down, it is “blowing” liquid helium. And with this technique, all the CUORE cubes sit at a brisk 10 millikelvins,  or -273.149 degrees Celsius. But temperature isn’t the only thing that  the experiment needs to carefully regulate.

CUORE’s radioactive cubes also need to  be shielded from any external sources of radiation and energy…lest the  extremely rare and extremely faint signal from a neutrinoless double beta  decay event be completely overwhelmed by even the slightest amount of background noise. And this is the reason why the entire  CUORE facility is located deep beneath the Apennine mountains, at the  Gran Sasso National Laboratory. Around 1.4 kilometers of solid  rock shields the experiment from the unceasing shower of neutrinos  raining down from outer space.

But even that isn’t enough. Because here’s something that you  don’t think about until it matters: Rocks themselves are slightly radioactive. Which means the Apennine Mountains…  also slightly radioactive.

So CUORE needed something to protect it from the protection it was  getting from the mountain. It’s like if you had a shield that  also, like, constantly stabbed you… Whether you are a fan of Superman or a  person who has gotten your mouth x-rayed at the dentist, you are probably  familiar with lead’s use as a shield against x-ray radiation. But lead is good at radiation shielding, period, because it’s just made of big, heavy  atoms that cluster close together.

That’s why it’s so heavy. That’s why half your arm’s worth of it  weighs as much as a 10-year-old child… Or a German shepherd. Or 1/50th of Kia Sorento.

This means tiny particles find it very  difficult to pass through even thin layers of the stuff, either just bouncing off the atoms’  nuclei or just getting absorbed by them. So it’s no surprise to see lead lining everywhere from nuclear reactors to,  yes, your dentist’s office. But there’s another problem.

Just like a rock can be radioactive in  trace amounts, so can a lump of lead. There are several kinds of non-radioactive  lead, but there is a small but significant amount of a radioactive kind called lead-210 that is present in any that  is mined from the Earth. And that stuff has a half life of 22 years.

Meaning 22 years after you mine a lump of lead, half the radioactive stuff will be gone. And it takes another 22 years for  half of that leftover half to decay. And so on and so forth.

So any lead that has been mined  in the last, say, hundred years, will still have an appreciable amount of lead-210. Which means that modern lead  is simply too radioactive to provide shielding for  CUORE’s sensitive detectors. But lead from the ancient world is another matter!

Lead that was processed by the  Romans more than 2000 years ago has had more than enough time to stabilize. And the stuff from an ancient  shipwreck is even better, because it spent all of those years underwater. Much like the Apennine mountains  protect CUORE from neutrinos and other subatomic particles  raining down from space, the Mediterranean Sea protected  the ship’s ingots from cosmic rays that could strike the lead atoms and  generate more unwanted radioactivity.

This kind of lead is so valuable and in-demand that physicists have a special term  for it: low-background material. But it’s typically found in small quantities,  in things like anchors and isolated ingots. So, not long after the shipwreck  near Mal di Ventre was discovered, the CUORE team took a keen  interest in the developments.

You may have noticed the very cool  swimming astronaut shirt Hank is wearing. And also that I am wearing. Well, it’s a reference to  NASA’s Neutral Buoyancy Lab, which we made an episode about back in June.

The pool is so big the water actually looks blue. You can get one of these shirts  for yourself at complexly.store The new home for merch from all  your favorite Complexly channels. And there is currently a summer sale happening!

We’ve got up to 50% items like a  3D-printed Kakapo from Bizarre Beasts, a False Crab Puzzle from Eons, and SciShow’s very own Orca Bucket Hat. Sale ends August 23rd! As fate would have it, the archaeologists  who were trying to excavate the Mal di Ventre ship were  struggling to bring it all up.

With the boat and ingots sitting 30 meters  below the waves, each diver could only spend about 30 minutes at the site  before having to return to the surface. A project that began in 1989  hadn’t made much progress in its first two years,  and they needed more money. And that’s when Italy’s National  Institute of Nuclear Physicists, which represents the CUORE scientists, approached Dr.

Salvi’s team with a proposition. In exchange for about 10 percent of the  lead ingots on the ship, the organization of physicists would provide a cool 300 million  lira to help bring up the ship’s artifacts, which was about $210,000 at the time. Which may not sound like a lot, but it  would be enough to keep the dives going.

Now, there was no getting  around what the physicists were going to do with these ingots, though. They would melt them down and create  shielding for their neutrino experiment. At the time, Dr.

Salvi described  the decision as “painful.” Even though the physicists promised to  claim only the worst preserved ingots and to assist in finding where they came from,  the bars were, of course, irreplaceable. When an artifact gets preserved  after archeologists first analyze it, they can always return to it when they  inevitably have further questions to ask, or new techniques to apply. Once an artifact is gone, it’s gone.

And this was not the first time that physicists had sought low-background  material from historical finds. Over the years, they’ve used lead  from several different sources, from old church roofs to the  keels from ancient shipwrecks. Because the practice involves  destroying ancient artifacts and can encourage illegal salvaging,  it’s become fairly controversial.

The team behind an experiment called  Cryogenic Dark Matter Search, for example, bought their low-background lead from a company that had pulled it from an  18th century French shipwreck. But it turned out that salvage and  sale wasn’t entirely above board. The company wound up getting  into trouble with French customs for the illegal trade of archeological artifacts.

And the United Nations Educational,  Scientific and Cultural Organization has condemned the recovery of  shipwrecks for any commercial means. So, yeah, you can imagine how torn  Dr. Salvi and her team must have felt when the organization of physicists  approached them with their offer.

Ultimately, though, they decided to take it. The archaeologists were worried  that if they took too long, the wreck might be plundered by  less conscientious salvagers. In which case, the artifacts would  be lost to science altogether.

Excavation resumed, and over the next five years, divers brought up hundreds of Roman relics. Most of the best ingots were moved to the  Civic Archaeological Museum in Cabras. Some of them are still on display today,  along with other artifacts from the wreck.

So if you ever find yourself in Sardinia, go take a picture of them and  send them to me, so I can see. And making good on their promise, the  physicists helped analyze the lead ingots to confirm both where and when they came from. Lead from different parts of the world  has subtly different compositions, which can be measured with precision instruments.

And these lead ingots had  compositions that placed their origins in the Sierra de Cartagena  mines in southern Spain. So even though we’ll never know where  the ship was heading when it sank, there is a solid chance that it left from Cartagena. That might sound like Rome was engaged  in a bit of international trade.

But at the time, southern Spain was solidly under the control of the Roman Republic. So these ingots help researchers speculate  that Rome preferred to extract ores from its foreign territories…in  particular Spain, Greece, Britain and Sardinia… rather  than those within Italy. Perhaps this was to preserve their own  supplies in the event of another civil war.

At the very least, it appears  they were focused on using the bulk of this lead themselves, instead  of exporting it to other foreign powers. And remember how I said that the  names stamped onto the ingots tell us the ship must have  sunk some time after 89 BCE? Well, archaeologists already knew that the Sierra di Cartagena  mines were abandoned by 50 BCE.

So unless someone allowed a bunch  of surplus ingots to sit around being useless for years and years  (like a 2002 Kia Sorento) we now know the Mal di Ventre wreck must have  happened between those two dates. Narrowing it down to a 40-year window two  millennia ago is practically a pinpoint! In the end, the Sardinian archeologists  were happy with the deal they struck.

Over the course of seven years, they  were able to excavate everything of archaeological value from the ship. But the work for the CUORE  physicists had just begun. In 2011, they finally obtained 120 of the  ingots, melted them down, and reshaped them into a six centimeter-thick shield to  surround their tellurium oxide crystals.

Once everything else was in place, the CUORE team began making their observations in 2017. The experiment required maintaining  both the coldest cubic meter in the known universe and its exceptional  radiation shielding for more than five years, with scientists monitoring  the detectors almost constantly. If anything was going to find  out the true nature of neutrinos and matter in the universe, this was it.

In 2024, the CUORE project  published its latest results. And they were … initially disappointing. After several years of observations, the team had failed to find any evidence  of neutrinoless double beta decay.

The hypothesis that neutrinos are their  own antiparticle remained unproven. And physicists were no  closer to solving the mystery of why our universe is full of matter. Every part of the experiment had worked perfectly, so this wasn’t a result of any  error or a fault in CUORE’s design.

Instead, it was an indication of how  rare this form of radioactive decay is, assuming it occurs at all. Just like with radioactive decay more  generally, particle physicists describe the time it takes for neutrinoless double beta  decay to happen using a half life. And thanks to CUORE, they  now believe its half life is at least 38 trillion trillion years.

For comparison, that’s about a million  billion times the current age of the universe. Listen, I know even that can’t help you that much. Maybe we can put it in terms of 10 year olds?

Kia Sorentos? Jessica Rabbits? It’s a big number!

But while that result isn’t particularly  helpful for solving whether or not neutrinos are their own antiparticle, or  answering why there’s matter in the universe, it isn’t like scientists have hit a  brick wall, with no plan to move forward. In fact, they’re already transforming  CUORE into its own upgraded successor. It’s called CUPID, or the ‘CUORE  Upgrade with Particle Identification’.

That’s right, the acronym has an  acronym as part of its acronym, and it is currently scheduled  to come online in late 2024. So we really did go from CUORE,  meaning “heart,” to CUPID, the guy. Who said physicists aren’t romantics?

The most important part of this upgrade  is swapping the tellurium oxide cubes out for blocks of lithium-molybdenum oxide. Which is a mouthful. But these new crystals will  be easier to monitor for any signs of that neutrinoless double beta decay.

Thanks to their different chemical make-up, the new blocks will produce a signal  that, assuming it actually happens, should stand out a lot more  against any background noise. And fortunately for archeologists,  upgrading CUORE into CUPID won’t require any additional ingots to  bulk up the pre-existing lead shield. But they might not want to celebrate just  yet, because CUPID isn’t the end game.

Neither is using Roman lead to hunt for one specific hypothetical  form of radioactive decay. CUORE’s lead shielding can  be useful for plenty of other high-precision physics experiments,  like the search for dark matter. Dark matter is, like, five times more  abundant than regular matter and antimatter, and it helps form structures on both  galactic and intergalactic scales.

But physicists have basically no clue what it is. And lest you think the only people  to benefit are theoretical physicists trying to explain the nuances of reality,  CUORE’s innovations may also find more practical applications, like in  future generations of quantum computers. In other words, physicists are  likely to need ancient lead from archeological sites for many years to come.

And while supply is an issue, a bigger  problem might be an ethical one. Physicists certainly don't want to  buy unethically-sourced material. But it isn’t always easy to trace the  provenance of low-background metals as it was in the case of  the Mal di Ventre shipwreck.

And whenever there’s demand, there  are people looking to exploit it, leading to not just unethical but  full-on illegal salvage operations. It’s clear that some formal resolution  and guidance is going to be needed. Something which archeologists  are actively pushing for.

But while we wait to see if any official  international laws get put on the books, we can look forward to the  stories told from both fields. We can admire the Roman artifacts, and  let archaeologists paint us a picture of what life was like 2,000  years ago on the Mediterranean. From a foreign national who felt a jolt of  pride stamping his name into a lead ingot, to a merchant sacrificing his boat so  pirates couldn’t profit from stolen cargo.

And we can also await the results of CUPID  and other particle physics experiments. Maybe someday soon, we will finally solve  the mystery of matter and explain how the entire universe as we know it came to be… ancient Roman lead and all. [♪ OUTRO]