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An Ancient Roman Shipwreck May Explain the Universe
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00:002,000 years ago, a Roman merchant ship was sailing across the Mediterranean Sea when
00:05something went wrong.
00:06Just off the western coast of Sardinia, the boat sank beneath the waves, condemning its
00:11sailors and cargo to the seafloor.
00:14On board, there were plenty of clay jars, dishes, and other artifacts, maybe a Roman
00:18ghost or two.
00:19But the ship's real prize was more than 30 metric tons of lead that had been processed
00:24into a thousand ingots.
00:26And while the ingots' original destination has been lost to history, their story was
00:31far from over.
00:32These bars were destined to serve a purpose far greater than anyone in the Roman Republic
00:37could ever conceive.
00:38Without the loss of that cargo, we'd be unable to run an experiment that hopes to
00:43answer fundamental questions about reality.
00:47Because in the 21st century, that shipment of ancient Roman lead is protecting the coldest
00:52cubic meter in the known universe.
00:55A cubic meter where scientists are hunting for what might be the rarest event in particle
01:01physics.
01:02If they find what they're looking for, we might finally understand the outcome of a
01:05cosmic war that ended 13.7 billion years ago.
01:10This is a very weird but true story of two different fields of science, archaeology and
01:15cosmology, colliding.
01:16I'm here to tell you how this ancient Roman shipwreck could help explain why you and I
01:21and everything else in the universe are here at all.
01:25[♪ INTRO ♪
01:28Our story begins just a bit after the Roman Empire crumbled to pieces, when neon leg warmers
01:34were in fashion and who framed Roger Rabbit was the highest-grossing film at the North
01:38American box office.
01:39People loved that movie.
01:41It was 1988, and about 10 kilometers off the Sardinian coast, scuba divers were investigating
01:46the seafloor, searching for shipwrecks and the artifacts that they might contain.
01:50In doing so, they stumbled upon an ancient treasure.
01:54Twenty-eight meters beneath the waves, hidden among the sand and seaweed, they spotted the
01:58unmistakable outline of a ship.
02:00And from the looks of the clay jars on board, it was Roman in origin.
02:04Now, Roman shipwrecks are actually pretty common throughout the Mediterranean.
02:08At their height, both the Democratic Roman Republic and the subsequent Roman Empire dominated
02:12the sea's European and African shores.
02:15They laid claim to every harbor, from Gibraltar to Turkey, and when you're that big, you're
02:20gonna lose a few boats.
02:21This particular shipwreck was found two kilometers east of a tiny island called Mal di Ventre,
02:25which might amuse some of you Italian speakers out there because it translates to stomach
02:30ache.
02:31But that's actually a likely mistranslation from the original Sardinian name meaning bad
02:34winds.
02:35Which may contribute to stomach aches, and also to shipwrecks.
02:39For more information, though, archaeologists needed to take both a figurative and a literal
02:43plunge.
02:44And that's when things started to get interesting.
02:48After 2,000 years, the sea had destroyed much of the ship's perishable parts, including
02:52most of its original wooden structure.
02:55But around 10 meters of the keel had been buried below the sandy seabed, and plenty
03:00of erosion-resistant metal and stoneware had survived as well.
03:04From these pieces, investigators could tell that the ship was much bigger and much beefier
03:10than most of the others that had been found around the Mediterranean.
03:13It was a novice honoraria magna, a class of sail-driven merchant ships that measured
03:18about 30 meters long and 9 meters wide.
03:21For comparison, that's about the same size as nine school buses parked in a 3x3 grid.
03:26It was huge.
03:27At one end of the wreck, archaeologists found items that the crew likely used during their
03:31journey.
03:32There were jars used for storing food, as well as water and wine.
03:35There was also a millstone, which the vessel's sailors would have used to grind their own
03:41grain in the middle of a voyage.
03:43But in the center of the wreck, there was an even more remarkable find.
03:46The ship's cargo included a thousand lead ingots, stacked as neatly as they would have
03:52been two millennia ago.
03:54Each of these ingots was roughly trapezoidal in shape, measuring 45 centimeters in length
03:58and 10 centimeters in height and width.
04:00In other words, like, roughly the length of your hand and forearm together.
04:04But because lead is so dense, these metal blocks were 33 kilograms a pop, or about the
04:08weight of a 10-year-old child, or like a German shepherd, or like a 50th of a Kia Sorento.
04:14So with more than a thousand of these ingots on board, this ship was lugging around a shipment
04:17of lead that weighed over 33 metric tons.
04:21And that explained why the wooden hull had been strengthened in some places with nails
04:25up to 80 centimeters long.
04:27Now, to an ancient Roman, lead was kind of a big deal.
04:30Along with their Greek neighbors, they mined and smelted so much of this stuff that evidence
04:35of this industry can be found as a layer of pollution in ice cores thousands of kilometers
04:41away in Greenland.
04:42It was actually one of the first metals that humans learned to extract from an ore, in
04:46this case, a mineral called galena.
04:48And it has a lot of properties that make it worth figuring out how to extract it.
04:52Lead is soft and easy to work with, but at the same time, it's durable and doesn't
04:57corrode easily.
04:58Plus, galena is also full of silver, which has its own uses.
05:02So even if you're trying to mine for silver, you end up with lead as a by-product.
05:05Bonus.
05:06In fact, Rome had such easy and abundant access to lead that at one point, policymakers had
05:12to step in and restrict how much was being produced.
05:16But despite that abundance, before the Maldiventre discovery, archaeologists had only managed
05:20to find a few lead ingots on shipwrecks scattered around the Mediterranean.
05:24So this find instantly became the biggest load of ingots ever recovered from the ancient
05:30world.
05:31Daniela Salvi, one of the lead archaeologists who investigated the wreck, told us in an
05:35interview that the discovery was of huge importance to Roman studies.
05:39By studying the unique construction of this merchant ship, which had been specialized
05:42for carrying such heavy loads, we can learn a lot about Roman engineering.
05:46But what about the lead itself?
05:48Unfortunately, we cannot know for sure exactly what the Romans had planned for this particular
05:52shipment.
05:53The metal's physical properties made it useful in a wide variety of products—coins,
05:57anchors, and slingshot ammunition, to name a few.
06:00Romans even used lead to line their aqueducts and build a network of water pipes that brought
06:05a reliable source of water to an enormous territory.
06:08That probably made the water somewhat toxic sometimes, but give them a break, it was 2,000
06:13years ago, and we were using lead in water pipes not that long ago ourselves.
06:17We might not know what these ingots were destined to become, but there is something we do know
06:21just by looking at them.
06:23Each one bears an inscription stamped on the top of it.
06:26And while that text might seem to us to be a nonsensical string of letters, it is actually
06:31telling us who cast it.
06:33For example, this one is shorthand for the Societas Marci et Caeo Pontianorum.
06:37In other words, it was made by a company owned by two Romans named Marcus and Gaius Pontinellius.
06:43Their company produced the majority of the ingots in this shipment—over 700 of them.
06:47And a subset of those ingots are also stamped with the letters P-I-L-I-P, which researchers
06:52believe is a tribute to a deceased servant called Philippus.
06:56Meanwhile, there are a bunch of stamps corresponding to other men in the lead manufacturing business,
07:01like Quinto Appio and Planio Russino.
07:04Professor Salvi told us this is invaluable information that paints a picture of both
07:08the entrepreneurs of the time and the powerful families that were involved in metal mining
07:13and trade.
07:14Together, these ingots tell us about how the Roman Republic managed its mines within its
07:19territory—that they were run by private individuals, as opposed to being directly
07:23run by the state.
07:25The inscriptions also help us narrow down exactly when this ship made its final journey.
07:30Because the names that the manufacturers use tell us that they identify as Roman citizens.
07:36And that was only possible when urban Italian tribes got representation in the Roman Republic.
07:40We know when the law that granted them that right was passed—it was 89 BCE.
07:46So we know the ship must have met its fate sometime after that.
07:50And yet, there are still a lot of pieces missing from this 2000-plus-year-old puzzle.
07:54Salvi says that archaeologists don't know where this shipment was headed, whether a
07:58delivery of this size was a one-off or a regular occurrence, and ultimately, what caused the
08:04ship to sink.
08:05But because the ingots were still neatly stacked on the remains of the hull, the ship must
08:10have sunk straight down.
08:11And there didn't seem to be any major damage to the hull, either.
08:14So it's possible that the region's famously bad winds could have destabilized the heavy
08:19load, causing the ship to take on water and dip beneath the waves.
08:23But some archaeologists think there is another possibility.
08:26During the first century BCE, the Roman Republic was in turmoil, with several civil wars raging
08:32across the territory.
08:33I mean, throw a dart at a timeline and you're going to hit some Roman turmoil.
08:37But things were particularly bad during that period, and it meant a lot of attacks on Roman
08:42boats.
08:43After a gentle descent to the seafloor, some researchers think that this merchant ship
08:47was deliberately sunk by its crew after something like a pirate attack to stop an enemy from
08:54seizing this extremely precious cargo.
08:58And if that's the case, we owe the crew of that ship our deep appreciation for their
09:02sacrifice, because nobody got their hands on that cargo until long after the fall of
09:08the Roman Empire.
09:09But it wasn't just modern archaeologists who wanted these ancient ingots.
09:14Researchers in a completely unexpected field also did, and those scientists hoped to use
09:19them to solve one of the universe's biggest mysteries.
09:24This SciShow video is supported by Babbel.
09:27Babbel is one of the top language learning apps in the world, with 14 different languages
09:30at your fingertips, including Italian, which comes in handy for this video.
09:35With Babbel's help, you wouldn't need us to translate Mal d'Aventure into Stomachache,
09:40because you'd know that already.
09:41Also, everything we learned from Professor Donatella Salvi was sent to us in an email
09:45written in Italian, so knowing multiple languages can come in handy when you least expect it.
09:51You can learn through a wide variety of lessons that prepare you to have practical conversations
09:55about travel, business, relationships, and more.
09:58There are also several subscription plans for you to choose from, including a Lifetime
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10:04Now, a Lifetime is a long commitment, but you can cut that subscription short and get
10:08all of your money back in the first 20 days if you find out it's not your thing.
10:12And when you sign up using the link in the description down below, you can get up to
10:1560% off.
10:17According to our best theories of the early universe, we shouldn't actually exist.
10:22And by we, I don't just mean you and me, I also mean, like, the Earth, and the Sun,
10:26and all the other stars, and neon leg warmers, and kioserentos, and black holes, and neutron
10:31stars.
10:32Everything.
10:33The universe is far older than any shipwreck.
10:34It all started shortly after the beginning of time itself, when the universe was in its
10:39Jessica Rabbit era, young and indescribably hot.
10:42The universe had expanded and cooled just enough to let some of its energy transform
10:47into matter and antimatter for the very first time.
10:50In an infinitesimally small amount of time, basically all of the stuff that would ever
10:56exist was born.
10:58But there's a problem.
10:59Whenever a particle of matter and its antimatter twin meet, they annihilate one another.
11:03In a literal flash of light, their mass gets converted into energy and rejoins the cosmic
11:08pool from whence it came.
11:10So if matter and antimatter are produced in equal amounts, which is what the laws of physics
11:14tell us, and they are destroyed when pairs meet up, the total amount of matter and antimatter
11:19in the universe should be… none.
11:22But you may have noticed, that's not the case.
11:25Otherwise, we wouldn't have hot dogs.
11:27From our observations of the universe, it appears the ratio of matter to antimatter
11:31was not exactly 1 to 1.
11:33It was more like 1 billion in 1 to 1 billion.
11:37In other words, for every 1 billion matter-antimatter pair annihilations that happened in our baby
11:42universe, there was somehow one matter particle left over.
11:46And eventually, those leftover matter particles came together to make every single star and
11:51planet and YouTuber, author, CEO, sock salesman.
11:55That's me.
11:56But we do not know how or why this happened.
11:58It's one of the biggest outstanding questions in particle physics right now.
12:02And scientists think the answer could lie with some of the most elusive subatomic particles
12:08of them all.
12:09They're called neutrinos.
12:11You can think of them as cousins to a more recognizable subatomic particle, the electron.
12:15But unlike electrons, neutrinos don't have an electric charge.
12:18They're also way less massive.
12:22Which is something, because electrons aren't exactly hefty.
12:24Put these two facts together, and you get a unique group of particles that almost never
12:29interact with other matter.
12:31In fact, as you are watching this, trillions of neutrinos are streaming through you without
12:37a single side effect.
12:38They can pass through an entire planet as if it isn't there.
12:42Now that means that there's nothing for you or I to worry about.
12:45But scientists have to worry about capturing them to learn how they work.
12:48So despite physics predicting that neutrinos existed about a century ago, we're still
12:53lacking some pretty basic information about them.
12:56Like, we still don't know how much mass they have, so I can't even tell you how many
12:59kioserentos they weigh.
13:00We know it's not nothing, but beyond that, it's kind of anyone's guess.
13:04Another big question is whether or not a neutrino can act as its own antiparticle.
13:08Now, this is where we're going to get a little more particle physics-y, so please
13:12stick with me.
13:13According to the Standard Model of Particle Physics, which is the theory that scientists
13:17rely on to understand the subatomic world, every matter particle has its own antimatter
13:23counterpart.
13:24For example, you've got protons and antiprotons, electrons and antielectrons.
13:28Each twin in a matter-antimatter pair has the exact same mass, but the opposite charge.
13:33Neutrinos, though, are neutral.
13:35So does that mean they don't have antiparticles?
13:36No.
13:37Turns out, charge is just one piece of the antipuzzle.
13:41There are other properties that I had never heard of.
13:44Things like lepton number and helicity.
13:46It's helicity!
13:47Oh, it's helicity.
13:50And those are also opposite and antiparticles.
13:52So antineutrinos are very much a thing.
13:55In fact, don't look now, but your body is currently emitting antineutrinos.
13:58No, really, don't look.
14:00You won't be able to see them.
14:01Weirder than that, though.
14:03Back in the 1930s, an Italian physicist named Ettore Majorana hypothesized that a neutrino
14:09could act as its own antiparticle.
14:12Such dual-acting particles have come to be known as Majorana particles.
14:16If scientists discover that neutrinos truly are their own antiparticle, for reasons that
14:21get pretty complicated pretty fast, it could explain why our universe is filled with matter.
14:26However, Majorana's hypothesis was just that, a hypothesis.
14:30And he made it in the early days of particle physics.
14:32Although the field has made a lot of strides since then, it has not made much progress
14:37on neutrinos.
14:38But we finally may be on the verge of having proof that Majorana was right.
14:44Deep beneath the Apennine Mountains in central Italy, physicists created an experiment.
14:49Its name was CUARE, which is Italian for heart, but of course, it's also an acronym,
14:54short for Cryogenic Underground Observatory for Rare Events.
14:58And part of CUARE's mission is to observe a hypothetical event in particle physics called
15:02neutrinoless double-beta decay.
15:04Basically, there are a few ways that unstable atoms release particles on their way to becoming
15:10stable atoms.
15:11Most of these forms of radioactive decay are garden-variety and well-understood by physics,
15:16but neutrinoless double-beta decay?
15:19Never been witnessed.
15:20And here's where you're going to have to trust us on two things, because the science
15:24is intense.
15:25First, neutrinoless double-beta decay would require neutrinos to be their own antiparticle.
15:31And second, neutrinos being their own antiparticle could have led to the accumulation of matter
15:37in the early universe.
15:38It is a multi-step process, I'm told that it's very complicated.
15:42So if any of you out there are craving an episode on leptogenesis and right-handed neutrinos
15:46and the seesaw mechanism, there is an internal debate going on at SciShow over whether we
15:50should cover it.
15:51So if you want to know, let us know in the comments.
15:54But remember, neutrinoless double-beta decay itself is hypothetical.
15:58It's never been observed before, which means if it does happen, it's an extraordinarily
16:03rare process that needs an extraordinarily large and sophisticated experiment to detect it.
16:10So before KUORI was able to get up and running, scientists had to start with some early, scaled-down
16:15proof-of-concepts.
16:16Basically, you'd need a lump of radioactive material and a detector that is sensitive
16:21enough to spot when antineutrinos are and are not present.
16:25So starting in the 1980s, experiments featured radioactive samples weighing just a few hundred
16:29grams.
16:30That's just a few Costco hot dogs.
16:32And over the decades, this got scaled up to over 700 kilograms inside the full-scale KUORI
16:37facility.
16:38For the radioactive element, the team went with tellurium-130, not only because it undergoes
16:42the kind of decay they needed, but because it does so with a really clear energy signature
16:48that will shine a beacon on any missing neutrinos.
16:51But it isn't one massive block of the stuff.
16:54Instead, KUORI houses nearly a thousand Rubik's cube-sized blocks of tellurium oxide crystals
16:59that have been arranged into 19 neighboring towers.
17:02That's a lot of weird units in this video.
17:05If neutrinoless double-beta decay does happen, then again for very complex reasons, the surrounding
17:11tellurium oxide cubes would heat up by a very small, but very specific amount.
17:17And that is why each crystal has an extremely sensitive thermometer on the surface.
17:21It's also why each crystal needs to be kept at an incomprehensibly frigid temperature.
17:27And by incomprehensibly, I mean it's about 270 times colder than the depths of outer
17:32space.
17:33It is the coldest cubic meter in the known universe.
17:37Like, literally, if there's a colder spot in the universe, it's because aliens made it.
17:42But the technique we use to create it is surprisingly simple.
17:45You know when you get a cup of coffee or, like, a bowl of soup that is just scalding
17:48hot and you cool it down by blowing over the top of it?
17:51Well, KUORI kind of does the exact same thing, except it isn't blowing air over the thing
17:56it's trying to cool down.
17:57It is blowing liquid helium.
18:00And with this technique, all of the KUORI cubes sit at a brisk 10 millikelvins, or negative
18:05273.149 degrees Celsius.
18:09But temperature isn't the only thing that the experiment needs to carefully regulate.
18:13KUORI's radioactive cubes also need to be shielded from any external sources of radiation
18:17and energy, lest the extremely rare and extremely faint signal from a neutrinous double beta
18:24decay event be completely overwhelmed by even the slightest amount of background noise.
18:30And this is the reason why the entire KUORI facility is located deep beneath the Apennine
18:34Mountains at the Grand Sasso National Laboratory.
18:38Around 1.4 kilometers of solid rock shields the experiment from the unceasing shower of
18:43neutrinos raining down from outer space.
18:45But even that isn't enough.
18:48Because here's something that you don't think about until it matters.
18:51Rocks themselves are slightly radioactive.
18:54Which means the Apennine Mountains also slightly radioactive.
18:58So KUORI needed something to protect it from the protection it was getting from the mountain.
19:04It's like if you had a shield that also, like, constantly stabbed you.
19:08Whether you are a fan of Superman or a person who has gotten your mouth x-rayed at the dentist,
19:12you are probably familiar with lead's use as a shield against x-ray radiation.
19:17But lead is good at radiation shielding, period.
19:20Because it's just made of big, heavy atoms that cluster close together.
19:24That's why it's so heavy.
19:25That's why half your arm's worth of it weighs as much as a 10-year-old child, or
19:28a German Shepherd, or a 50th of a Kyocerendo.
19:31This means tiny particles find it very difficult to pass through even thin layers of the stuff,
19:36either just bouncing off the atom's nuclei or just getting absorbed by them.
19:40So it's no surprise to see lead lining everywhere from nuclear reactors to, yes, your dentist's office.
19:46But there's another problem.
19:48Just like a rock can be radioactive in trace amounts, so can a lump of lead.
19:53There are several kinds of non-radioactive lead, but there is a small but significant
19:57amount of a radioactive kind, called lead-210, that is present in any that is mined from
20:03the Earth.
20:04And that stuff has a half-life of 22 years.
20:07Meaning, 22 years after you mine a lump of lead, half the radioactive stuff will be gone,
20:12and it takes another 22 years for half of that leftover half to decay, and so on and so forth.
20:18So any lead that has been mined in the last, say, hundred years will still have an appreciable
20:23amount of lead-210.
20:25Which means that modern lead is simply too radioactive to provide shielding for Kiwara's
20:31sensitive detectors.
20:32But lead from the ancient world is another matter.
20:36Lead that was processed by the Romans more than 2,000 years ago has had more than enough
20:41time to stabilize.
20:43And the stuff from an ancient shipwreck is even better, because it spent all those years
20:46underwater.
20:48Much like the Apennine Mountains protect Kiwara from neutrinos and other subatomic
20:52particles raining down from space, the Mediterranean Sea protected the ship's ingots from cosmic
20:57rays that could strike the lead atoms and generate more unwanted radioactivity.
21:03This kind of lead is so valuable and in demand that physicists have a special term for it
21:08— low-background material.
21:11But it's typically found in small quantities in things like anchors and isolated ingots.
21:16So not long after the shipwreck near Maldiventre was discovered, the Kiwara team took a keen
21:20interest in the developments.
21:23You may have noticed the very cool swimming astronaut shirt Hank is wearing.
21:27And also that I am wearing.
21:28Well, it's a reference to NASA's Neutral Buoyancy Lab, which we made an episode about
21:31back in June.
21:32The pool is so big, the water actually looks blue.
21:35You can get one of these shirts for yourself at Complexly.store, the new home for merch
21:39from all of your favorite Complexly channels.
21:41And there is currently a summer sale happening!
21:44We've got up to 50% off items like a 3D-printed kakapo from Bizarre Beasts, a false crab puzzle
21:49from Eons, and SciShow's very own orca bucket hat.
21:54Sale ends August 23rd.
21:57As fate would have it, the archaeologists who were trying to excavate the Maldiventre
22:01ship were struggling to bring it all up.
22:03With the boat and ingots sitting 30 meters below the waves, each diver could only spend
22:07about 30 minutes at the site before having to return to the surface.
22:10A project that began in 1989 hadn't made much progress in its first two years, and
22:16they needed more money.
22:18And that's when Italy's National Institute of Nuclear Physicists, which represents the
22:22Cuore scientists, approached Dr. Salvi's team with a proposition.
22:26In exchange for about 10% of the lead ingots on the ship, the Organization of Physicists
22:31would provide a cool 300 million lira to help bring up the ship's artifacts, which was
22:36about $210,000 at the time.
22:38Which might not sound like a lot, but it would be enough to keep the dives going.
22:42Now, there was no getting around what these physicists were going to do with these ingots,
22:46though.
22:47They would melt them down and create shielding for their neutrino experiment.
22:51At the time, Dr. Salvi described the decision as, quote, painful.
22:55Even though the physicists promised to claim only the worst-preserved ingots, and to assist
23:00in finding where they came from, the bars were, of course, irreplaceable.
23:05When an artifact gets preserved after archaeologists first analyze it, they can always return to
23:10it when they inevitably have further questions to ask, or new techniques to apply.
23:15Once an artifact is gone, it's gone.
23:18And this was not the first time that physicists had sought low-background material from historical
23:23finds.
23:24Over the years, they've used lead from several different sources, from old church roofs to
23:28the keels from ancient shipwrecks.
23:30Because the practice involves destroying ancient artifacts and can encourage illegal salvaging,
23:35it's become fairly controversial.
23:37The team behind an experiment called Cryogenic Dark Matter Search, for example, bought their
23:41low-background lead from a company that had pulled it from an 18th century French shipwreck.
23:46But it turned out that salvage and sale wasn't entirely above board.
23:50The company wound up getting into trouble with French customs for the illegal trade
23:54of archaeological artifacts.
23:56And the United Nations Educational, Scientific, and Cultural Organization has condemned the
24:00recovery of shipwrecks for any commercial means.
24:03So yeah, you can imagine how torn Dr. Salvi and her team must have felt when the Organization
24:09of Physicists approached them with their offer.
24:12Ultimately, though, they decided to take it.
24:14The archaeologists were worried that if they took too long, the wreck might be plundered
24:18by less conscientious salvagers, in which case the artifacts would be lost to science altogether.
24:24The investigation resumed, and over the next five years, divers brought up hundreds of
24:28Roman relics.
24:30Most of the best ingots were moved to the Civic Archaeological Museum in Cabras.
24:34Some of them are still on display today, along with other artifacts from the wreck.
24:37So if you ever find yourself in Sardinia, go take a picture of them and send it to me
24:42so I can see.
24:43And making good on their promise, the physicists helped analyze the lead ingots to confirm
24:47both where and when they came from.
24:50Lead from different parts of the world has subtly different compositions, which can be
24:54measured with precision instruments.
24:56And these lead ingots had compositions that placed their origins in the Sierra de Cartagena
25:00mines in southern Spain.
25:01So even though we'll never know where the ship was heading when it sank, there's a
25:04solid chance that it left from Cartagena.
25:08That might sound like Rome was engaged in a bit of international trade.
25:11But at the time, southern Spain was solidly under the control of the Roman Republic.
25:16So these ingots helped researchers speculate that Rome preferred to extract ores from its
25:21foreign territories—in particular, Spain, Greece, Britain, and Sardinia—rather than
25:26those within Italy.
25:27Perhaps this was to preserve their own supplies in the event of another civil war.
25:31At the very least, it appears they were focused on using the bulk of this lead themselves,
25:37instead of exporting it to other foreign powers.
25:39And remember how I said that the names stamped onto the ingots tell us that the ship must
25:43have sunk sometime after 89 BCE?
25:46Well, archaeologists already knew that the Sierra de Cartagena mines were abandoned by
25:5150 BCE.
25:53So unless someone allowed a bunch of surplus ingots to sit around being useless for years
25:57and years like a 2002 Kia Sorento, we now know the Maldiventre wreck must have happened
26:03between those two dates.
26:05Narrowing it down to a 40-year window two millennia ago is practically a pinpoint.
26:10In the end, the Sardinian archaeologists were happy with the deal they struck.
26:14Over the course of seven years, they were able to excavate everything of archaeological
26:18value from the ship.
26:20But work for the Kewere physicists had just begun.
26:22In 2011, they finally obtained 120 of the ingots, melted them down, and reshaped them
26:28into a 6-centimeter-thick shield to surround their tellurium oxide crystals.
26:33Once everything else was in place, the Kewere team began making their observations in 2017.
26:37The experiment required maintaining both the coldest cubic meter in the known universe
26:43and its exceptional radiation shielding for more than five years, with scientists monitoring
26:48the detectors almost constantly.
26:50If anything was going to find out the true nature of neutrinos and matter in the universe,
26:55this was it.
26:56In 2024, the Kewere project published its latest results.
27:00And they were… initially disappointing.
27:03After several years of observations, the team had failed to find any evidence of neutrinoless
27:09double beta decay.
27:10The hypothesis that neutrinos are their own antiparticle remained unproven, and physicists
27:16were no closer to solving the mystery of why our universe is full of matter.
27:21Every part of the experiment had worked perfectly, so this wasn't a result of any error or
27:26a fault in Kewere's design.
27:28Instead, it was an indication of how rare this form of radioactive decay is, assuming
27:34it occurs at all.
27:36Just like with radioactive decay more generally, particle physicists describe the time it takes
27:41for neutrinoless double beta decay to happen using a half-life.
27:45And thanks to Kewere, they now believe its half-life is at least 38 trillion trillion
27:50years.
27:51For comparison, that's about a million billion times the current age of the universe.
27:56Listen, I know even that can't help you that much.
27:59Maybe we can put it in terms of 10-year-olds, Kioserentos, Jessica Rabbits.
28:02It's a big number!
28:04But while that result isn't particularly helpful for solving whether or not neutrinos
28:08are their own antiparticle, or answering why there's matter in the universe, it isn't
28:12like scientists have hit a brick wall with no plan to move forward.
28:16In fact, they're already transforming Kewere into its own upgraded successor.
28:20It's called CUPID, or the Kewere Upgrade with Particle Identification.
28:25It's right, the acronym has an acronym as part of its acronym.
28:29And it is currently scheduled to come online in late 2024.
28:32So we really did go from Kewere, meaning heart, to CUPID, the guy who said physicists
28:38aren't romantics.
28:39The most important part of this upgrade is swapping the tellurium oxide cubes out for
28:43blocks of lithium molybdenum oxide, which is a mouthful.
28:47But these new crystals will be easier to monitor for any signs of that neutrino-less double
28:51beta decay.
28:52Thanks to their differing chemical makeup, the new blocks will produce a signal that,
28:55assuming it actually happens, should stand out a lot more against any background noise.
29:00And fortunately for archaeologists, upgrading Kewere into CUPID won't require any additional
29:05ingots to bulk up the pre-existing lead shield.
29:08But they might not want to celebrate just yet, because CUPID isn't the endgame, and
29:12neither is using Roman lead to hunt for one specific hypothetical form of radioactive
29:17decay.
29:18Kewere's lead shielding can be useful for plenty of other high-precision physics experiments,
29:22like the search for dark matter.
29:24Dark matter is, like, five times more abundant than regular matter and antimatter, and it
29:29helps form structures on both galactic and intergalactic scales.
29:33But physicists have basically no clue what it is.
29:36And lest you think the only people to benefit are theoretical physicists trying to explain
29:40the nuances of reality, Kewere's innovations may also find more practical applications,
29:46like in future generations of quantum computers.
29:48In other words, physicists are likely to need ancient lead from archaeological sites for
29:53many years to come.
29:55And while supply is an issue, a bigger problem might be an ethical one.
30:00Physicists certainly don't want to buy unethically sourced material.
30:04But it isn't always easy to trace the provenance of low-background metals, as it was in the
30:09case of the Maldiventre shipwreck.
30:11And whenever there's demand, there's people looking to exploit it, leading to not just
30:15unethical, but full-on illegal salvage operations.
30:18It's clear that some formal resolution and guidance is going to be needed, something
30:22which archaeologists are actively pushing for.
30:25But while we wait to see if any official international laws get put on the books, we can look forward
30:29to the stories told from both fields.
30:31We can admire the Roman artifacts, and let archaeologists paint us a picture of what
30:35life was like 2,000 years ago on the Mediterranean.
30:38From a foreign national who felt a jolt of pride stamping his name into a lead ingot,
30:43to a merchant sacrificing his boat so pirates couldn't profit from stolen cargo.
30:48And we can also await the results of Cupid and other particle physics experiments.
30:52Maybe someday soon, we will finally solve the mystery of matter and explain how the
30:57entire universe as we know it came to be.
31:01Ancient Roman lead and all.
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