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It's ALL THINGS CONSIDERED from NPR News. I'm Audie Cornish.
ROBERT SIEGEL, HOST:
And I'm Robert Siegel.
A little bit of the science of cities now, as part of the NPR Cities Project.
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SIEGEL: Cities are built on physical systems: buildings, streets, plumbing, wires. And as NPR blogger and astrophysicist Adam Frank has been telling us, modern cities are great places to see the laws of physics at work. Out on the street, you can see traffic flowing like fluid. From a rooftop, you can see heat shimmering off the buildings as energy is consumed by the people working inside. Adam has taken us on those excursions in past conversations, now the view of the city from 20,000 feet up.
Adam Frank, urban physicist, is at the airport today. Welcome once again.
ADAM FRANK, BYLINE: Oh, it's great to be here.
SIEGEL: And you're at Rochester International. Tell us about the principles of physics and the aerial view.
FRANK: Well, what I'm thinking about today is really the view of cities from the grandest perspective. And in that sense, it's the city as a driving force in the evolution of the planet. So, why am I here at the airport? Because I can see all these travelers and what are they going to do? They're about to get on airplanes and they're going to, you know, fly up to 20 or 30,000 feet.
And it's from that view that they're going to be able to see not just the structure of individual cities but they're going to see how cities are interconnected, how they're basically vast sprawling networks of interconnected human habitations. And it's the cities that are the nodes of those networks.
So I'm going to walk over to the flight and departure board - the arrival and departure board that we're all familiar with - and take a look at some of the flights we have. OK, so there's one going to looks like D.C., right?
FRANK: So what do the people who are flying to Washington, D.C. from Rochester going to see? Well, particularly if they're flying anywhere near the coast, what they're going to see is the entire eastern seaboard is almost one giant axis of urban area.
SIEGEL: But, Adam, you're here to talk with us about physics. So what does that 20,000-foot view of the cities have to do with physics?
FRANK: Right, when you look at cities from that view what you do is you shift from physics to astrophysics, a planetary view of cities. And what I think is best to start thinking about astrobiology. And what astrobiology shows us is the way planets and life go together. Some researchers call this back and forth co-evolution. And what they mean by that is that life and the planet can change the course of each other's history.
SIEGEL: So what you're saying is that when we're flying over cities at night and we're seeing these clusters and ribbons of lights, we're seeing a form of co-evolution. We're seeing cities as an extension of organic beings.
FRANK: To me, that's the way I look at it. I really do see it as co-evolution. And so, those vast geometries that you see traced out in light, in some sense, they're showing us a kind of infestation. They're like living networks that spread across the planet. You know, far from the cities, what's going on? You're harvesting energy, whether it's food and petrochemicals to power those cities.
And then, through those tendrils - the pipelines, the roads - you're bringing that energy into the cities and that's what's fostering the growth of those cities. So what you see from 20,000 feet with all those lights and that land use, is the way we're changing the planet in ways that we can obviously see and ways we can't see, like climate change.
SIEGEL: Yeah, you referred earlier to life and us as an infestation, which isn't very positive. Is it appropriate? Are you talking about life as a parasitic invasion? Do you mean to be that negative?
FRANK: No, it's really - really the question is negative for whom, right? This has been going on for a long time. And from the astrobiolgical perspective, whether it's good or bad doesn't change the fact that it's happening. So, you know, some scientists looking at the way life and planet evolve have even coined a new term for what's going on right now. There's lots of geological epochs, right - the Pliocene, the Holocene.
And now folks are suggesting that what we're entering is a new epoch, the Anthropocene; when all of our activity actually pushes the planet and its systems in new directions. And when you think about it, the Anthropocene really is the epoch of the city. So that spider web of lights that you're seeing from 20,000 feet is a real marker. It's the physical manifestation of life, meaning us and our cities, changing the planet.
And what I think is really remarkable is this practice of city building, which started 4,000 or 6,000 years ago, has exploded to become such a powerful force on the planet. That's both really impressive and pretty scary at the same time.
SIEGEL: Some big thoughts about cities as seen from up high and as seen from Rochester, New York, from Astrophysicist Adam Frank. Thanks, Adam.
FRANK: Oh, it's been a pleasure.
SIEGEL: And you can find our other conversations with Adam and other stories from the NPR Cities Project at NPR.org/nprcities.
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