When the Universe was still very young, only a few kinds of atoms existed. Astrophysicists believe that around 100,000 years after the Big Bang, ionized hydrogen and neutral helium atoms combined to make the helium hydride ion (HeH+) for the first time. This molecule should be present in some parts of the modern Universe, but it has never been detected in space — until now. A team of researchers from the United States, Germany and France discovered...
