A rare gravitationally lensed supernova from the early universe could help solve one of cosmology’s biggest mysteries—the true speed of cosmic expansion. Credit: Shutterstock Astronomers may be getting closer to understanding one of the biggest mysteries in cosmology: dark energy, the unknown force believed to be driving the accelerating expansion of the universe. Dark energy is thought to account for about 68% of the universe. Despite its enormous influence, scientists still do not know what