Utilizing the infrared-sensitive instruments of the joint NASA, European Space Agency, and Canadian Space Agency James Webb Space Telescope, as well as observations from the Hubble Space Telescope, scientists recently collected the first spectroscopic observations of some of the oldest galaxies in the universe, some being born during the first one billion years of the universe.
These galaxies are thought to be a product of the reionization of the universe — the dark, star-less period of the universe wherein a dense fog of hydrogen gas covered the universe until the first stars began to ionize the hydrogen gas around them. As more and more stars began to ionize the gas, the universe gradually brightened.
For decades, astronomers have been trying to identify what objects emitted radiation that was powerful enough to clear the hydrogen fog, and Webb’s new observations are giving scientists insight into what these sources may be.