WEBVTT 99:59:59.999 --> 99:59:59.999 (Male announcer) Thank you for downloading from the BBC. 99:59:59.999 --> 99:59:59.999 For details of our complete range of podcasts and our Terms of Use, 99:59:59.999 --> 99:59:59.999 go to bbcworldservice.com/podcasts . 99:59:59.999 --> 99:59:59.999 (Female announcer) Governments worldwide battle to control and contain terrorism. 99:59:59.999 --> 99:59:59.999 Police and the courts struggle to separate harmless loners from dangerous lone wolves. 99:59:59.999 --> 99:59:59.999 Opinions differ on the most effective way to combat terrorist attacks, 99:59:59.999 --> 99:59:59.999 from military interventions on the ground, to curbing political and religious radicalisation. 99:59:59.999 --> 99:59:59.999 But in this edition of Discovery, we'll be hearing about a more unusual new weapon 99:59:59.999 --> 99:59:59.999 that might be used in the future to fight terrorism: 99:59:59.999 --> 99:59:59.999 maths (1:00) 99:59:59.999 --> 99:59:59.999 (A) We were looking at the data in a new way, we were using tools that were somewhat foreign, 99:59:59.999 --> 99:59:59.999 (A) these were tools that came out of physics and complex systems, not tools that necessarily came out of the political science community. 99:59:59.999 --> 99:59:59.999 (A) And we were saying things that were kind of weird. 99:59:59.999 --> 99:59:59.999 (B) One thinks of terrorism as something very random, something so strange that it must be done in a very chaotic way. 99:59:59.999 --> 99:59:59.999 (B) But of course, in the end, it is an activity, it's a human activity, so it's quite interesting then that the patterns that you seen in the events are not random. 99:59:59.999 --> 99:59:59.999 (A) For terrorism, that had somewhat shocking implications. 99:59:59.999 --> 99:59:59.999 (A)If you understand the frequencies of the small events, you can extrapolate, 99:59:59.999 --> 99:59:59.999 (A) and then make a forecast out into the future, about what the probability should be 99:59:59.999 --> 99:59:59.999 (A) for a very large event. 99:59:59.999 --> 99:59:59.999 (HF) So, could maths predict the next 9/11? 99:59:59.999 --> 99:59:59.999 (HF) You're listening to the BBC World Service, and today on Discovery, I'll be looking at the hidden mathematical pattern that is being discovered in global terrorism; 99:59:59.999 --> 99:59:59.999 (HF) a pattern that lies behind a host of diverse phenomena, from economics to earthquakes. 99:59:59.999 --> 99:59:59.999 (HF) I'm Dr Hannah Fry, and I'm a mathematician from University College London, working on complex systems. 99:59:59.999 --> 99:59:59.999 (HF) These are systems, like terrorism, which at first seem complex, and random 99:59:59.999 --> 99:59:59.999 (HF) but if you stand back and study the bigger picture, then a surprising number of patterns can appear; 99:59:59.999 --> 99:59:59.999 (HF) patterns which you can describe using mathematics. 99:59:59.999 --> 99:59:59.999 (HF) Dr (?), a computer scientist at the University of Colorado, was one of the first to find a tangible, mathematical connection underlying terrorism. 99:59:59.999 --> 99:59:59.999 (HF) He looked at 30,000 terror attacks worldwide, over 40 years 99:59:59.999 --> 99:59:59.999 (HF) and for all of the events, he counted how many times a certain number of people were killed, and plotted it on a graph 99:59:59.999 --> 99:59:59.999 (HF) and the results were remarkable. 99:59:59.999 --> 99:59:59.999 (Dr) This initial analysis we did, it was quite shocking, we found this thing that looked like 99:59:59.999 --> 99:59:59.999 (Dr) what's called a power law distribution, which is a very special kind of mathematical pattern that usually 99:59:59.999 --> 99:59:59.999 (Dr) crops up in physics, in fact, but increasingly is observed in social and biological systems, 99:59:59.999 --> 99:59:59.999 (Dr) and this is somewhat surprising, because when we think about terrorism, 99:59:59.999 --> 99:59:59.999 (Dr) we think mainly about the capricious, highly contextualised nature of the individual actors 99:59:59.999 --> 99:59:59.999 (Dr) that carry out these events, 99:59:59.999 --> 99:59:59.999 (Dr) and yet, at the global level, we see this remarkable pattern, this power law pattern, emerge. 99:59:59.999 --> 99:59:59.999 (HF) So it's obviously a bit tricky to describe a graph on the radio. (Dr) [Laughs] Yes. 99:59:59.999 --> 99:59:59.999 (HF) but could you give us an idea of what a power law looks like, 99:59:59.999 --> 99:59:59.999 (HF) perhaps, compared to some other distributions that people might be familiar with? 99:59:59.999 --> 99:59:59.999 (Dr) So a power law distribution is very different from 99:59:59.999 --> 99:59:59.999 (Dr) what most of us experience, and our intuition is built around, as human beings. 99:59:59.999 --> 99:59:59.999 (Dr) Most of our world is wrapped up in what are called Gaussian, or normal, distributions. 99:59:59.999 --> 99:59:59.999 (Dr) So, the range of heights that we experience among other humans, 99:59:59.999 --> 99:59:59.999 (Dr) has what's called a normal distribution. (HF) Like a bell curve. 99:59:59.999 --> 99:59:59.999 (Dr) [Confirming] Like a bell curve. Which means that there's an average, 99:59:59.999 --> 99:59:59.999 (Dr) that is representative of essentially the entire population. 99:59:59.999 --> 99:59:59.999 (NJ) One of the first graphs that we ever draw in school is one of heights of people in the classroom 99:59:59.999 --> 99:59:59.999 (HF) Neil Johnson, professor of Physics at the University of Miami. (4:14)