Astronomers have finally located the universe’s missing hydrogen gas, essentially uncovering half the cosmos like it was behind the cosmic couch cushions all along. It’s a win for astrophysics and a reminder that even the universe loses track of its stuff—just on a slightly more galactic scale.

By tracing faint filaments of hydrogen gas strung between galaxies, the discovery of this “missing” hydrogen reshapes our understanding of cosmic structure. The phrase “half the universe found” is no exaggeration—hydrogen gas forms much of the unseen framework connecting the universe.