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ASU researchers help connect ancient, modern metropolises

ASU metropolis research published this month in PLOS ONE.
Study on cities first to document patterns using historical records.
October 21, 2016

In recently published paper, interdisciplinary scientists say cites across time grow at similar rates

Mih-tutta-hang-kusch, a Mandan village on the upper Missouri River in the 1830s.

Leicester, a large town in medieval England, 1300.

Manhattan, 2016.

What do they all have in common? What bridges the ancient and modern worlds, villages and global capitals? 

A group of interdisciplinary scientists, including four with ties to Arizona State University, analyzed census records, maps and archaeological studies of medieval cities across western Europe to show that their populations grew at the same rate as modern cities and prehistoric New World settlements.

It’s the first study to document these patterns using historical records. The paper was published this month in PLOS ONE.

So why is this the case? What processes are common to people living together in numbers? What benefits and costs have remained the same in the Southwestern cliff dwelling, the Mayan city and the medieval cathedral town?

Researchers say social and economic outputs get multiplied when cities get bigger. A city twice as big as the next one doesn’t have twice as much wealth; it has more than twice as much wealth, said archaeologist Mike Smith, a professor in the School of Human Evolution and Social Change who is a member of the working group.

“So in bigger cities something is going on that doesn’t go on in smaller cities,” Smith said. “It’s not just that people are learning something different. They’re producing things — more wealth, more knowledge. You have these regular relationships. You can predict these things mathematically. They’re found in the modern world. They’re found around the world. They’re found in ancient times. They’re found in historical times. There’s something basic and fundamental about people living in cities, and it’s hard to put a finger on exactly what that is. We’re just trying to figure it out.”

Rudy Cesaretti, a grad student in archaeology at ASU, was the paper’s lead author.

Based at the University of Colorado Boulder anthropology department, the Social Reactors Project is comprised of economists, physicists, and archaeologists. Their goal is to identify common properties of all human settlements, and how they generally grow and decline.

“We refer to human settlements as social reactors due to their role in concentrating and accelerating social interactions and their outcomes in space and time,” the group’s statement reads. “This view derives from urban scaling research and the discovery that some emergent properties of modern cities are also apparent in pre-modern and even non-urban settlements.”

Smith explained settlement scaling research.

“It gets down to how people interact within cities, how people interact with one another,” he said. “When you have more people, you have more interaction. When you have denser cities, you have more interaction. You get the similar pattern you get with modern cities. The number of rock bands in a city. The city is twice as big. You’d expect to have twice as many rock bands. If a city is twice as big, it has more than twice as many rock bands than smaller cities. Why is that? There’s something about people in bigger cities; there’s more going on. There’s more interaction. They need more rock bands per person. For me, a lot of this is surprising and amazing.”

The research could tell how cities grow and shrink. One of the things that’s most important is that as many people as possible interact with each other socially, according to Smith. The key concept is called energized crowding. It refers to the social effects of large numbers of social interactions in a city (or town or village). Energized crowding generates a lot of outcomes, which can be mathematically predicted.

“Whatever this energized crowding creates, whether it’s more rock bands, more wealth, more patents,” Smith said. “That kind of thing is generated by people interacting and talking and learning and getting together in cities. ... Cities are ‘social reactors.’ A greater output comes out, somehow.”

three people walking in ancient city

ASU professor Mike Smith (left) walks down the Avenue of the Dead in the ancient city of Teotihuacan with museum studies graduate students Kate Rush and Lisa Gallagher. Photo by Ken Fagan/ASU Now

Smith initially thought scaling theories worked in modern cities because of modern economies. But it’s not dependent on capitalism; it’s dependent on people interacting in a built environment. This works regardless of economies. For instance, wage labor and land as a commodity, both staples of capitalism, didn’t exist in medieval cities.

He looked at census records from medieval towns taken 10 to 15 years apart. “The turnover is like 50 percent,” he said. “It’s incredible. These aren’t people bound to the land who never moved. They moved around quite a bit. And they moved into cities.”

Non-related people living together in groups is a distinctive Homo Sapiens trait, from hunting camps to Tokyo. The group’s goal is to form a theory of human aggregation, said Jose Lobo, a member and associate research professor in the School of Sustainability.

“Our goal is to identify common properties of all human settlements, and general processes of growth and decline, in a framework that accommodates both regularity and contingency,” Lobo said. “We are developing a framework that frames all human settlements, from hunter-gatherer camps to modern megacities, as concentrations of people, things, energy and information in space and time.”

Medieval cities can teach us quite a bit about modern cities, said archaeologist Scott Ortman of the University of Colorado Boulder. Ortman earned his doctorate at ASU. The regular economies of scale across such a wide variety of societies suggest that the forces driving them are strong and predictable.

“Policies that promote more livable cities should lead to a wide range of social, economic and environmental benefits over the long term,” Ortman said.

The work done by the group dissolves the boundary between past and present and turns the archaeological record into “a compendium of long-term experiments in social dynamics,” he said. “This is important because it provides a new way of leveraging collective human experience in our efforts to build a better tomorrow.

“I think the inexorable increase in the scale of human settlements over time shows that, on an evolutionary level, human beings benefit in open-ended ways from getting along with strangers,” Ortman said. “On balance, the more people interact the better off everyone becomes.”

The study was funded by a grant from the McDonnell Foundation to Scott Ortman at Colorado; and the Arizona State University – Santa Fe Institute Center for Biosocial Complex Systems. Physicist Luis Bettencourt of the Santa Fe Institute is a member of the group.

Scott Seckel

Reporter , ASU News


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Cubesat mission on track, poised for breakthroughs

Cubesat spacecraft can be about as small as a Rubik’s cube.
ASU mission marks first time for cubesats to go to deep space.
October 21, 2016

ASU reaches one-year mark on endeavour that could create new standard for space exploration

About two years from now, the most powerful rocket ever built will roar off from the Florida coast. Carrying a new spacecraft built for humans on a test voyage, it will claw into low Earth orbit before the upper stage separates from the core and fires itself towards the moon. 

Once headed toward the moon, the Orion spacecraft will disengage from the engine that sent it into deep space. When it’s safely away, the engine will spit out 13 cubesats, which will make their own way to the moon. One of them is being built at Arizona State University.

It’s a lot of firsts. It’s the first time cubesats — spacecraft that can be about as small as a Rubik’s cube — will go interplanetary, and the first time a mothership will carry a number of spacecraft along on secondary missions.

“In the future, (NASA is) going to say, ‘You want to go to Venus? When we’re at Venus, we then deploy 13 separate missions,’” said ASU planetary geologist Craig Hardgrove. “And this is kind of the test case for this.”

It’s also the first NASA mission won by ASU, bestowed a year ago. The university has taken part in 25 missions to eight planets, three asteroids, two moons and the sun, but always as a guest, never a host. Because of their small size and relatively low cost, cubesats are bringing space within reach of universities and private institutions.

And it’s the first NASA mission for Hardgrove, an assistant professor in the School of Earth and Space Exploration.

“It’s a trip,” he said. “It’s been a year of a lot of telecons, a lot of meetings, a lot of traveling to different places to meet with subcontractors who are providing the propulsion system, the reaction wheels and everything to make sure we’re all on the same page to get ready for the design reviews.”

Craig Hardgrove

ASU planetary geologist and assistant professor Craig Hardgrove looks at an early version of the CubeSat shell as he talks about starting preliminary design and construction of the engineer development units, or brains, of the flight hardware for the cubesat Oct. 14 in Tempe. The final components will be smaller when the shoebox-size satellite is launched to the southern hemisphere of the moon in two years. Photo by Charlie Leight/ASU Now

Hardgrove flies almost as much as his spacecraft will. ASU’s cubesat will combine six small units into one, a 6U in space parlance. (To give you an idea of its size, if it was built he could carry it in an overhead bin.) To Boston and Colorado, to meet with subcontractors. To the Jet Propulsion Lab in Pasadena. To NASA centers, hither and yon.

About 50 people are working on LunaH-Map, the Lunar Hydrogen Polar Mapper. It’s a tiny operation compared with typical NASA missions. And the usual prime contractors, the Lockheeds and Boeings, aren’t interested because a $2 million mission isn’t worth their time.

“They don’t want to build one-off solar arrays for a cubesat,” Hardgrove said. “And they’re not going to charge what we can pay them. So the traditional players are out.”

“It’s a very different model,” he added later, “for how a spacecraft gets built.”

A NASA mission led by a principal investigator — the holder of a grant administered by a university and the lead scientist; in this case, Hardgrove — has a number of built-in review steps. LunaH-Map passed its mission concept review (how and what they want to achieve) and a preliminary design review. The team is proceeding cautiously.

“You come out with a bunch of lists of things to improve and work on over the next few months, which is what we want,” Hardgrove said. “So I’ve asked them to put as critical an eye as you possibly can on this, because that’s the only way we’re going to uncover the things that we don’t know we don’t know.”

Cubesats were created about 10 years ago as a classroom engineering exercise. Now they regularly fly in low Earth orbit. Internet stores sell parts or completely assembled cubesats. Hardgrove’s team can’t use those parts because LunaH-Map is going into deep space, where radiation would fry off-the-shelf components.

For now, all involved have met their schedules, made their deliveries, and passed their reviews.

“We’re on track,” Hardgrove said.

LunaH-Map artist rendition

The Lunar Hydrogen Polar Mapper, or LunaH-Map, will orbit around the lunar poles 141 times during 60 days sniffing for hydrogen. Artist rendition by Sean Amidan

This is all new ground, for Hardgrove and for NASA. With a $500 million or a $2 billion mission, careers and lives can be on the line. With that much money and responsibility, it’s a very serious operation.

“It’s a completely different model for how to do a spacecraft mission,” Hardgrove said.

“The idea with cubesats is that you’re able to do this more often, you reduce the price. You can’t just reduce the price arbitrarily; you have to lose something. In our case, I think you lose mission certainty. You’re taking more risks. And so, if you’re OK with that, you’re OK with it getting better over time. Then you can reduce the costs and ideally you get more of these things happening.”

LunaH-Map will orbit around the lunar poles 141 times during 60 days sniffing for hydrogen, flying about 10 kilometers (about 6 miles) above the surface, transmitting what it finds back to Earth. Then, having done its job, it will crash into the south pole.

Its job is part of NASA’s hunt for water on the moon. If ice is discovered on the moon, water wouldn’t have to be hauled from Earth. Ice can be used for rocket fuel or to support a human push to Mars.

In the meantime, 2018 will be the year of the cubesat in space. If LunaH-Map or one of the other cubesats succeeds, motherships carrying independent secondary spacecraft will be standard NASA practice.

“When we do this in the future it will be these risky missions, but if you get data, it’s a great reward,” Hardgrove said. “If you lose it, OK. No risk to the primary mission, we’re still doing all that, but we learned something. We learned something how to make it better. And I think that’s exciting for NASA and a bunch of other groups. ... Hopefully, when this works or one of the other 13 works, these will the new type of small, or nanosat developers that NASA can work with to make these types of payloads.”

Top photo: Preliminary work is starting with an emulator for the radio, larger than the one that will be used in in the LunaH-Map cubesat, in a lab at ISTB4 on Oct. 14 on the Tempe campus. Photo by Charlie Leight/ASU Now

Scott Seckel

Reporter , ASU News