Long, infrared exposures of giant gas and dust clouds reveal structures that are invisible at optical wavelengths (Image: J Foster and A Goodman, CfA) Astronomers have discovered a new way to probe dark clouds of gas and dust in space, shedding light on the mysterious conditions that nurture star birth. Stars condense from giant clouds of molecular gas and dust that float through space. But these stellar wombs are difficult to study because they are barely visible at optical wavelengths. And other methods that probe their structure are not very precise – for example, estimating how much dust they...