A series exploring the biggest questions on the frontiers of science. NOVA Wonders takes viewers on a journey to the frontiers of science, where researchers are tackling some of the biggest questions about life and the cosmos. The universe is hiding something. Everything we experience on Earth, the stars and galaxies we see in the cosmos—all the “normal” matter and energy that we understand—make up only 5% of the known universe. The other 95% is made up of two mysterious components: "dark matter" and "dark energy. " Scientists are trying to shed light on the so-called "dark sector" as the latest generation of detectors rev up, and powerful telescopes peer deeper into space than ever before to observe how it behaves. Will the discoveries help reveal how galaxies formed?