According to the Big Bang theory, there were only clouds of hydrogen and helium in the newborn universe. Then neutral helium atoms combined with hydrogen ions to form the first molecule: helium hydride ion (HeH +). She became the progenitor of all other chemical formations, but the trouble is - until recently, scientists could not find traces of HeH + in space, which called into question the whole concept.
In laboratory conditions, HeH + was synthesized almost a century ago, in 1925. And this was not a very pleasant fact for astronomers, because logic dictated that such molecules in the Universe should be everywhere and in abundance, like traces of ancient events. And exactly the opposite situation was observed, which led scientists to a dead end. And only having received the opportunity to take the measuring instruments out of the troposphere, they realized what was what.
HeH + leaves a spectral trail at a limiting frequency of 2.01 THz, which is blocked by the Earth's atmosphere. Therefore, it was necessary to construct a stratospheric observatory for observations in the infrared range (SOFIA). It is based on board a Boeing 747SP aircraft, which rises to an altitude of 14 km, from where observations are made. And already in the first flight, the team discovered the spectral signature of HeH + in the envelope of the planetary nebula NGC 7027.
As predicted by the scientists, there was an abundance of HeH + molecules in space. Thus, they managed to find the oldest molecule in our universe and confirm the theory of the chemical primogeniture.
Equipment on board the SOFIA observatory