The evolution from the first molecule to the complex chemistry that exists in our universe today is now one step closer to being understood.
When we think of complex chemistry, we usually think of all the matter that exists on our planet which in our atmosphere is a massive 10 trillion trillion molecules per cubic meter. As we move away from our planet this drops exponentially. However, surprising as it may be, space space – like the interstellar and intergalactic regions – are host to a myriad of molecules. Albeit not at quite the same high densities.
How these molecules formed and became the complex chemistry that we see today remains to be fully understood. It is currently agreed that the early universe consisted of only a few kinds of atoms and it wasn’t until the age of 100,000 years that hydrogen and helium combined to form the first molecule – helium hydride. However, although theorized to exist it has never been detected. That was until a team of scientists from NASA’s SOFIA Science Center (Stratospheric Observatory for Infrared Astronomy) observed its signature – in our own galaxy.
Previously, scientists were able to successfully combine helium and ionic hydrogen to create helium hydride in the laboratory. They then speculated that astrophysical plasmas such as those found in planetary nebulae – an expanding shell of dust that has been ejected from its host star as it runs out of fuel – provided the prefect environment for helium hydride to form. The young, dense planetary nebula, NGC 7027, located around 3,000 light-years from Earth in the constellation Cygnus, seemed like the perfect candidate. However, the instruments of the time were not sufficient to distinguish its signal and the observations were thus inconclusive.
Finally, in 2016, utilizing the world’s largest airborne observatory SOFIA, scientists were able observe NGC 7027 above the interfering layers of Earth’s atmosphere and clearly distinguish the elusive signature of helium hydride.
By: Dr. Amira Val Baker, RSF research scientist