Universe's First Molecule | 19 Apr 2019

Scientists have detected the most ancient type of molecule in our universe in space for the first time ever.

  • Helium hydride ion (HeH+) was the first molecule that formed when, almost 14 billion years ago, the falling temperatures allowed recombination of the light elements (hydrogen, helium, deuterium and traces of lithium) produced in the Big Bang.
    • It is the first type of molecule (first molecular bond) that formed in the universe after the Big Bang.
  • At that time, ionised hydrogen and neutral helium atoms reacted to form HeH+.
    • Once the universe cooled down, hydrogen atoms started to interact with helium hydride, creating molecular hydrogen, which set the stage for star formation.
    • From that point on, stars created the other elements of the cosmos.
  • Despite its importance in the history of the early Universe, HeH+ has so far escaped detection in astrophysical nebulae — cloud of gas and dust in outer space.
  • Helium hydride — a combination of helium and hydrogen — was detected roughly 3,000 light-years from Earth by NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA).

Stratospheric Observatory for Infrared Astronomy

  • Stratospheric Observatory for Infrared Astronomy (SOFIA) is a Boeing 747SP jetliner modified to carry a 100-inch diameter telescope. It is a joint project of NASA and the German Aerospace Centre.
  • It is flown at approx 45,000 feet, where its observations are not impacted by interference from Earth's atmosphere.
  • SOFIA returns to Earth after every flight, allowing scientists to regularly update the instrument with the latest technology. One of the most recent upgrades included adding a specific channel to detect signatures of helium hydride, which previous telescopes did not have.
  • The molecule was found in a planetary nebula, NGC 7027, which is the dusty remnant of a sun-like star.
  • While helium hydride has been produced and tested in a laboratory setting, this discovery marks the first time that this molecule has been detected in space — which sheds light on the chemistry of the early universe.