Physics

Astronomers finally find the first molecule ever formed in the universe

Astronomers finally find the f...
The planetary nebula NGC 7027, where astronomers found the first unambiguous detection of the helium hydride ion molecule
The planetary nebula NGC 7027, where astronomers found the first unambiguous detection of the helium hydride ion molecule
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The spectrum of HeH+ as detected by SOFIA
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The spectrum of HeH+ as detected by SOFIA
The planetary nebula NGC 7027, where astronomers found the first unambiguous detection of the helium hydride ion molecule
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The planetary nebula NGC 7027, where astronomers found the first unambiguous detection of the helium hydride ion molecule
The GREAT far-infrared spectrometer, which is part of the SOFIA observatory
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The GREAT far-infrared spectrometer, which is part of the SOFIA observatory

After a decades-long search, astronomers have finally found the very first molecule to ever form in the universe. The helium hydride ion (HeH+) has long been a key theoretical part of how the chemistry of the cosmos kicked off, but its apparent absence in space had scientists worried they'd gotten it wrong. Now the first unambiguous evidence of the molecule in a planetary nebula has been found.

The story goes that soon after the Big Bang, hydrogen and helium dominated the young universe. Eventually, neutral helium atoms combined with ionized hydrogen to form HeH+, which would have been the first type of molecule possible from the ingredients available. That in turn opened up different combinations that gradually snowballed into the extensive chemical library we know today.

That's all well and good in theory, but confirmation that that was how it happened has eluded scientists for decades. HeH+ was first produced in the lab way back in 1925, but despite the expectation that it should be naturally abundant in the interstellar medium, the molecule had never been observed until now.

"The chemistry of the universe began with HeH+," says Rolf Güsten, first author of the study. "The lack of definitive evidence of its very existence in interstellar space has been a dilemma for astronomy for a long time."

The spectrum of HeH+ as detected by SOFIA
The spectrum of HeH+ as detected by SOFIA

The problem is that HeH+ emits its strongest spectral line at a frequency of 2.01 THz, which Earth's atmosphere can block. To get past that, scientists have now used NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA), which can scour the cosmos from its perch onboard a Boeing 747SP. Since this mobile observatory flies at an altitude of up to 45,000 ft (13,700 m), it can get an unobscured view of the required infrared wavelengths.

And sure enough, using SOFIA the team spotted the telltale spectral signature of HeH+ in the envelope of the planetary nebula NGC 7027.

"The discovery of HeH+ is a dramatic and beautiful demonstration of nature's tendency to form molecules", says David Neufeld, co-author of the study. "Despite the unpromising ingredients that are available, a mixture of hydrogen with the unreactive noble gas helium, and a harsh environment at thousands of degrees Celsius, a fragile molecule forms. Remarkably, this phenomenon can not only be observed by astronomers but also understood using theoretical models that we have developed."

The research was published in the journal Nature.

Source: Max Planck Institute for Radio Astronomy

4 comments
JeremyHinton
... and I'd have guessed that H2 would have been the first molecule...
Thinker
So, God used helium hydride to create man, not dust? Hmmm. You’re almost there to prove God doesn’t exist. Rather, have faith in your limited knowledge.
Douglas Bennett Rogers
Presumably, this is after the first batch of hydrogen stars. HeH is the first chemical compound. The God of the Bible is external to nature and speaks everything into existence, including time. The one exception, Man , is created by God entering into nature. The antedeluvian world is a hollow sphere with water on the outside, half full of water on the inside, with a floating land mass on the surface of the water. Gravity is provided mainly by acceleration. This provides enough time dilation to compress 13B years into 1600 years.
Pmeon
The Big Bang theory was first proposed by Georges Lemaître a Catholic Priest. Why? To fit the narrative of creation. That theory is actively promoted by the Max Planck Institute and main stream science. Why? Who pays the bills, who donates the money. Science and religion are both a modern day con and the stories from both camps complement each other. The history of civilised man dates back 6000 years, why? to fit the narrative in the bible.