Bad Plumbing? There Goes The Empire

IRA FLATOW: This is Science Friday. I’m Ira Flatow coming to you today from the studios of KMUW in Wichita, Kansas. How do you judge the state of the economy? Well, new homes, housing starts is always one indicator, and now that economic indicator has been adopted by historians. Researchers have discovered that the rise and fall of the Roman Empire can actually be seen through its plumbing, sort of, like it’s housing starts. Joining me as we plunge into the world of ancient pipes, as well as other short subjects in science, is my guest Annalee Newitz, Tech Culture Edtor for Ars Technica. Welcome back.

ANNALEE NEWITZ: Hi, thanks for having me.

IRA FLATOW: So the Romans were a big fan of their plumbing systems. I mean, how did researchers use this to track the rise and fall of the empire?

ANNALEE NEWITZ: It’s a really interesting story, because we’ve known from written records and archeology that the Romans used lead pipes. And this group of researchers in France wanted to know how many pipes they’d had at what times, how extensive was the pipe system. And so the way that they did it was to use a technique that’s often used in geology, which is that they took soil cores from one of the ancient Roman harbors called Ostia. And all of the pipes in the city basically dumped out into the harbor, kind of, the way sometimes happens today.

And they took the soil sample, and they were able to see layers of lead that corresponded to periods in the Roman Empire when there was a lot of economic growth. And so the more lead they saw, the more pipes they speculated were in use during that period of time. And they saw a lot of really interesting patterns.

IRA FLATOW: So they could tell how healthy the economy was or how well they were doing at any period?

ANNALEE NEWITZ: Basically as the pipe system expanded, what it meant was that the empire was spreading, because they got lead from the colonies in Europe. So they had to have an extensive trade network, and also maintaining a huge system of pipes is incredibly expensive. And there’s actually this fantastic treatise that was written by a Roman water commissioner in the early part of the first millenium. His name was Frontenis, and he talked extensively about how there were all these troubles with maintaining the pipes. They had to recycle all of the pipes, and, of course, the ever present problem of water piracy.

IRA FLATOW: Of course. But does this shed any new light on that old theory that the fall of the Roman Empire was caused by lead poisoning? You know what I’m talking about.

ANNALEE NEWITZ: Yeah, there was a very popular scientific theory in the 80s that because the Romans had these extensive lead pipe networks, that Emperor Claudius, for example, had lead poisoning, because he was known to have had a lot of physical disability, and he had speech impediments. And so this doctor theorized that maybe he had lead poisoning. However, since that time, since the 80s when this article was published, a number of researchers have debunked that claim.

So I think consensus now is that probably there was not enough lead in the water to result in any kind of significant lead poisoning, and as I was saying earlier, the more we see of the pipes, the more indication we have of economic growth and prosperity in the empire. So it’s really the pipes are correlated with the rise of the empire rather than the fall of the empire.

IRA FLATOW: Interesting. Let’s move on to your next story. This is, kind of, cool also where researchers figured out how Neanderthals were able to make tar. Why is that important? So Neanderthals were making about 200,000 years ago in Europe, which is long before homosapiens ever had access to tar technology. So you can think Neanderthals for inventing tar. And the thing that’s really fun about this research is that the researchers did what’s called experimental archeology, which means they tried to use the tools available to Neanderthals at the time, which was basically stones, wood, fire, ashes, the ability to dig holes, things like that, and they tried to recreate how they would have made tar.

And what they discovered was that it was actually relatively easy. They made it from birch bark, and it’s the kind of thing that many different groups of Neanderthals probably stumbled on, because they were heating birch up in the fire. And they would have found that if birch was exposed to heated embers, that eventually it would, kind of, extrude this like black sticky goo which was perfect for using to make tools. Because they were making compound tools that were two or more components like a rock stuck to a stick, a very carefully carved rock. And so having a little bit of adhesive in there really improved the performance of the tool.

IRA FLATOW: We were talking about this in the office the other day, and we were reminded of the Brea Tar Pits in Los Angeles. And there must have been other naturally occurring tar pits. Why didn’t they– why don’t we think they got them from nature?

ANNALEE NEWITZ: Well, we have evidence that they were making tar all throughout Europe, and naturally occurring tar pits are not everywhere. So there may have been some that stumbled on tar pits and kind of connected the dots, but it’s much more likely that this was a technology that they stumbled on basically through heating up birch bark. And we know that that would not have been available to homo sapiens back in Africa. There just wasn’t birch available to them. So it’s likely that Neanderthals made this great innovation partly out of luck, but partly because they were really smart.

[LAUGHS]

IRA FLATOW: I’ll go with that. Let’s move on. Researchers now suspect that women were the key to spreading cultural innovations in the Bronze Age. How did they arrive at that conclusion?

ANNALEE NEWITZ: This is a great study because it was such an unexpected finding. Some researchers were looking at a large number of women who had been buried in the Lech Valley. It’s a river valley in very, sort of, southern Bavaria and Germany, and there had been continuous settlement there from the Neolithic through the Bronze Age. So, basically, this great turning point in civilization when people started to manufacture bronze. And they analyzed these skeletons of women, genetically and chemically, and found that they almost all had come from far away to live there. They were all from– they had been born in other places.

And what that suggested was that there was a common practice of exogamy, where women would marry outside of their group, out of their village, and then journey to their new family and come to live with them. And the thing that always comes up when you hear this is it makes you think, well, but maybe women– that means that they weren’t treated very well, or they were kind of forced to leave home. But, actually, the other thing they found was that matriarchal lineage was very important in these burials, and they found many generations of women being buried next to each other, often with similar kinds of grave goods. And there’s one grave they found where there were two women who may have been separated by as many as 10 generations who’d been buried together, and they knew they were the same family from analyzing them genetically. So these people very much valued women’s relatedness to each other, but they also brought women in from outside for marriage, and those women would have brought lots of different cultural innovations with them and would have helped to spread knowledge about things like making bronze, for example.

IRA FLATOW: Yeah. Could you give us any more details on what kinds of innovations we’re talking about?

ANNALEE NEWITZ: So it could have– a lot of it was probably cultural. When I said, you know, the idea that they might have helped people understand how to make bronze. They would have brought ideas about how to make new tools. They might have spread new languages. There’s still a lot of variety of dialects spoken in that river valley today. They would have brought understanding of how to make ceramics, probably what kinds of foods you could cook and how. Which, again, at that time, was really cutting edge stuff. Having ceramics, having bronze– that would have been just like having a really awesome Android phone.

And so now we know that the primary driver of cultural sharing in that area was probably from women who would come from far away and bring you information about cool new innovations, and how to mix copper with arsenic, or whatever– however they were making bronze at the time.

IRA FLATOW: Very interesting. Our last story is another wild story, so to speak. It’s not only do wild dogs vote, but they do it by sneezing.

[LAUGHTER]

ANNALEE NEWITZ: So–

IRA FLATOW: I’m not making this up, right?

ANNALEE NEWITZ: No, you’re– this appears to be true based on the evidence. So a group of researchers in Botswana went to a national park and were following a group of wild dogs around for about a year, and recorded these social gatherings that the dogs have. They travel in packs, and they have these social gatherings called rallies where one dog kind of calls the rally and then the dogs vote on whether to go hunting or stay there. And the way they vote is they make this kind of sneeze noise. It’s not like a human sneeze. It’s kind of a ‘chh’ noise, which dog owners are probably familiar with, even though these wild dogs are only distantly related to domestic dogs.

And what the researchers found– they recorded about 68 of these rally sessions, and the more sneezes they heard, the more likely the dogs were to go off hunting. Sometimes they would stay. There weren’t enough sneezes. However, if the pack leader is the dog that called the meeting, that called the rally and gave a sneeze, they didn’t need as many sneezes to get going on this hunting expedition. So some votes count more than others among wild dogs. I have never heard of that in any other species.

IRA FLATOW: I don’t know. You look at Congress, you might change your mind a little bit. Thanks, Annalee. I just want to point out that– you know that Cassini will be ending his 20 year long mission next Friday, and we’ve learned a lot about Saturn from that orbiter over the years, haven’t we? I mean that’s going to be sort of a very sad event, isn’t it?

ANNALEE NEWITZ: It is going to be sad. It’s been 20 years of a great space robot and I still remember when it first spotted waterspouts coming from Enceladus, Saturn’s moon, which was the first time that we really had an inkling that there was an ocean underneath the ice on that moon. And, you know, it’s found– we’ve learned just so much from Cassini. So I’m going to be very sad to see it go.

IRA FLATOW: Yeah, because we’re going to be doing special coverage of Cassini when it takes its final plunge. And it is slated to do it on Friday, Science Friday. So we’ll be doing a lot of coverage on that. It will be– it is kind of sad because we have learned so much about the rings and about the moons and things like that, and scientists have spent so many years of their time studying it, so. It’s–

ANNALEE NEWITZ: Yeah, and it’s going to take a dive right into the atmosphere on Saturn. So I’ll be tuning in next week to hear what you guys find out about the last moments.

IRA FLATOW: All right. Thank you, thank you, Annalee Newitz, tech culture editor for Ars Technica. And, as I said, next week, we’re going to do a special 20 year anniversary of the Cassini mission. The orbiter showed us the lakes at Titan, geysers on Enceladus, and, of course, the gorgeous rings of Saturn up close and personal. And we’ve been covering Cassini since the beginning, and we’ll be watching it at the end with our producers live on the scenes at NASA’s JPL. And so we want you to tune in next week for special coverage– interviews, reminiscing, a celebration of everything the spacecraft has shown us.

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