Primordial Molecule

Discovery of Helium Hydride underlines mankind’s unending quest for truth

- K. Sahasranaman

ON April 17, Nature, the venerable science journal, announced that the first molecule of our universe has been detected in outer space. The molecule in question, Helium Hydride, was found in the gaseous clouds of a planetary nebula, known to astronomers as nG7027. This momentous discovery was made by a team of radioastronomers using a specially-built instrument mounted on a modified aircraft that was flown at a height of 14,000 metres to avoid the interference from earth’s atmosphere.

To understand Helium Hydride we need to travel back to the Big Bang which kick started our universe 13.8 billion years ago. Even several thousand years later, the universe was extremely hot and completely gaseous. To be more precise, it was made up of only two gases—hydrogen and helium—which incidentally are the two most abundantly found elements in the universe. It would take hundreds of thousands of years for the universe to cool down sufficiently for the various metals that we are familiar with to appear. But at the dawn of the universe, there were only hydrogen and helium and since the temperature was high, both were completely ionised.