An artist's impression of a window into the heart of a little red dot, revealing the supermassive black hole within. (Image credit: NASA/CXC/SAO/M. Weiss; adapted by K. Arcand and J. Major.) The discovery of an X-ray signal coinciding with the location of one of the mysterious 'little red dots' found by the James Webb Space Telescope (JWST) has strengthened the theory that the dots are 'black hole stars' — huge, dense clumps of gas energized by the presence of a growing supermassive black hole within them. The little red dots may be the biggest cosmological discovery made so far by the JWST, and possibly the most important since the discovery of dark energy in 1998. If they are what astronomers think they are, then they would act as a crucial missing link in the formation of not only supermassive black holes but also the galaxies that grow around them.…