This week, Exxon acquired XTO Energy, one of the largest domestic producers of natural gas. Natural gas is considered a cheaper and greener form of energy due to its somewhat lower carbon footprint... but the companies who may own the natural gas market may wind up being the same oil giants we already know. Daniel Yergin, chairman of IHS Cambridge Energy Research Associates, is joined by Lisa Margonelli, from the New America Foundation, to explain what these developments in the natural gas market signify.