Add caption Up until now, it's only been possible to track where cells are in their life cycle once they're dead. However, a new study outlines a method of analysing living cells by taking a close look at their nucleus. The new study by researchers at New York University (NYU), as published in the journal Proceedings of the National Academy of Sciences (PNAS), has established a method of gauging what stage of the cell cycle a living cell is currently at. Human cell nuclei with the nuclear envelope highlighted in green. (New York University/Alexandra Zidovska/Fang-Yi Chu) Using a cutting-edge fluorescence microscope , researchers were able to observe a previously undetected flicker of the nuclear envelope, which takes place over the course of just a few seconds. The amplitude of this fluctuation was seen to decrease as the cell cycle went on. This motion could serve as an internal clock, as scientists could take measurements in order to und...