Arlie Petters profile – Arlie Petters, a native of Belize, holds a joint appointment in the math and physics departments at Duke University, where he studies optical lensing – using light as a metric to understand how gravity behaves in the universe. He developed the mathematical tools to research dark matter, black holes and the age of the universe, and will test a new five-dimensional "braneworld" theory of gravity that competes with Einstein's Theory of Relativity (which has four dimensions). 

 

 

Epigenetics – It seems the environment in which we live makes small chemical changes to our DNA without affecting our genes' overall makeup. Experiences may trigger these switches and turn genes on or off. These subtle changes can then be "remembered" and passed on from generation to generation, altering inherited traits. "Nova" explores this new idea, interviewing top scientists in the field and following what could be a shift in the way we think about inheritance and our genes. 

 

 

 

Emergence – In any large group of individuals, there is a leader with a plan, right? Well, not always. Scientists are finding that order doesn't necessarily spring from the top down. Complex group behaviors emerge spontaneously: thousands of starlings flock as one, schools of fish evade predators in what seems like a highly choreographed dance, neurons in our brains fire in rapid, coordinated succession. This phenomenon, called "emergence," is transforming math, biology, cognitive science and the way we perceive the world. 

 

 

CERN LHC – It could be the boldest experiment in all of science, one that could answer a profound question: What is the universe made of? CERN, the particle physics lab in Switzerland, is constructing a new particle accelerator, the Large Hadron Collider (LHC). With a 17-mile circumference, the structure is essentially a giant circular magnet with protons zipping around inside of it. Scientists are trying to detect the elusive Higgs, also known as the "God particle" for its essential role in particle physics, which supposedly accounts for the mass of all other particles – if only researchers could find it. With luck, the LHC will do just that and in the process answer unsettled questions about the nature of matter.