Rain cloud? (IMAGE) Max-Planck-Gesellschaft Caption Not every dense cloud brings rain. Rain falls in a normal way in unpolluted air from this cloud over the Amazon (left). In contrast, no rain fell from another cloud on the same day due to the cloud being encumbered with a high number of aerosols caused by fire clearance -- the moisture droplets remained too small (right). Credit Left: Meinrat Andreae, MPI for Chemistry; right: Daniel Rosenfeld, Hebrew University, Jerusalem Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.