The detection of physical forces is one of the most complex challenges facing science. Although Newton solved the problem of gravity long ago, imaging the physical forces that act within living cells remains one of the main mysteries of current biology. Considered to play a decisive role in many biological processes, the chemical tools to visualize the physical forces in action do not exist. But today, researchers from the University of Geneva (UNIGE) and the National Centre of Competence in Research (NCCR) in Chemical Biology, Switzerland, have developed probes that can enter into cells and image live physical forces. These results, a turning point in the study of life sciences, can be found in the Journal of the American Chemical Society.