By Will Dunham WASHINGTON (Reuters) - Since beginning operations last year, the James Webb Space Telescope has provided an astonishing glimpse of the early history of our universe, spotting a collection of galaxies dating to the enigmatic epoch called cosmic dawn. But the existence of what appear to be massive and mature galaxies during the universe's infancy defied expectations - too big and too soon. That left scientists scrambling for an explanation while questioning the basic tenets of cosmology, the science of the origin and development of the universe. A new study may resolve the mystery...