After decades of relentless searching, scientists have finally detected signatures of the universe’s first molecule. Using NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA), the largest airborne observatory in the world, astronomers found the molecule in our own galaxy.
Known as helium hydride, the first type of molecule formed around 100,000 years after the Big Bang. Scientists believe that after the event, helium and hydrogen combined to form the molecule. Although long theorized, it’s existence has never been detected until now.
Astronomer Rolf Güsten from the Max Planck Institute for Radio Astronomy said:
“The lack of evidence of the very existence of helium hydride in the local Universe has called into question our understanding of the chemistry in the early Universe. The detection reported now resolves such doubts.”
The Search for the First Molecule
Located some 3,000 light-years away from Earth in the constellation Cygnus, SOFIA discovered signs of helium hydride in the planetary nebula NGC 7072.
The discovery not only proves that the first molecule indeed exists in space, but it also confirms a significant part of our current understanding of the early universe’s chemistry and how it evolved to build the complex chemistry we know today.
During the late 1970s, scientists reported that the environment of NGC 7027 might potentially be right for helium hydride to form. It was said that the heat and ultraviolet radiation coming from the star present the proper conditions for the creation of the elusive molecule.
Unfortunately, technological limitations of the time made it hard for scientists to detect signatures of helium hydride within the nebula. However, the development of SOFIA and its German Receiver at Terahertz Frequencies or GREAT instrument significantly improved the observations of modern scientists.
Harold Yorke, SOFIA Science Center’s Director, said in a statement:
“This molecule was lurking out there, but we needed the right instruments making observations in the right position — and SOFIA was able to do that perfectly.”
SOFIA’s GREAT instrument acts as a radio receiver. All scientists have to do is fine tune it to the frequency of the molecule they are searching in space. Güsten added:
“It was so exciting to be there, seeing helium hydride for the first time in the data. This brings a long search to a happy ending and eliminates doubts about our understanding of the underlying chemistry of the early universe.”
Helium hydride ions really do exist in space. Is it molecular hydrogen would have been the first molecule in the universe?
The helium ions He2+ and He+ were the first to combine with free electrons, forming the first neutral atoms. This is the oldest type of molecule that cannot detect in the space but not anymore.