Astronomers have discovered a huge reservoir of cold molecular gas, the direct fuel for star formation, in REBELS-25, a massive, star-forming galaxy.The team, led from Leiden University, focused on REBELS-25, seen when the universe was only about 700 million years old, around 5% of its current age. Astronomers use “redshift” to describe this distance, which measures how much the universe’s expansion has stretched a galaxy’s light to redder wavelengths.