Using the unprecedented capabilities of the NASA/ESA/CSA James Webb Space Telescope, an international team of scientists has obtained the first spectroscopic observations of the faintest galaxies during the first billion years of the universe. These findings, published in the journal Nature, help answer a longstanding question for astronomers: What sources caused the reionization of the universe? These new results have effectively demonstrated that small dwarf galaxies are the likely producers of prodigious amounts of energetic radiation.