Scientists think that helium hydride is the universe’s first chemical bond, yet the ion has proven surprisingly difficult to locate.
Key takeways
- Scientists have finally detected the first molecular bond ever formed in the universe, the helium hydride ion (HeH+), in space.
- HeH+ was created just after the Big Bang, making it the first compound to form from different elements, but it had been elusive in space until now.
- The discovery was made using the Stratospheric Observatory for Infrared Astronomy (SOFIA), an observatory on an aircraft that flies above Earth’s atmosphere to get clear observations.
- The HeH+ ion was found in NGC 7027, a planetary nebula 2,900 light-years away, helping scientists understand the behavior of these nebulas better.
- This discovery confirms fundamental theories about early universe chemistry and helps researchers develop more accurate models of cosmic evolution.
Everything has its origin. That holds true for tales, people, the world, and even chemistry. The Big Bang created just a few elements (variations of hydrogen, helium, and lithium nuclei), thus scientists have a reasonable idea of what the initial atoms and molecules would have been. However, the first molecular bond to form, which linked atoms from various elements in a single molecule, has long been absent from activity. Known as a helium hydride ion (HeH+), this conglomeration of basic bits is just a helium atom and a hydrogen’s nucleus (aka a proton) stuck together. As the first compound created in the universe, you’d expect there to be traces of it throughout the universe — but astronomers couldn’t find it. (Scientists managed to produce some in the lab in 1925, so at least they knew it wasn’t an impossible substance.)
However, just when scholars pondered if they had gotten things incorrect about the early cosmos (or fundamental chemistry), fate smiled on them: A report published today in Nature presents the first definitive detection of the HeH+ molecule in space. It needed precise instruments and a flying observatory to do it, but now chemists and cosmologists can breathe comfortably – and push their studies farther.
SOFIA So Fine.
Since the 1970s, astronomers have been searching for HeH+ molecules in nebulas, which are hazy collections of gas and dust. Some, known as planetary nebulas, might recreate circumstances in the early cosmos, making them the primary targets. But for decades, astronomers discovered nothing. (Well, nothing definitive; some helium hydride results came in, but they were all unverified.)
Part of the difficulty was that the light emitted by the molecule was easily absorbed by the Earth’s atmosphere. The air around most observatories was obscuring the molecule’s signal. To get a decent view, scientists actually had to rise above it all.
Most observatories are constructed high on mountains for a variety of reasons, but even that wasn’t sufficient for this quest. Instead, scientists resorted to the Stratospheric Observatory for Infrared Astronomy, or SOFIA, which is basically an observatory atop an aircraft. They lifted their telescope above all of the obscuring air and discovered clear and unmistakable HeH+ ion emissions from NGC 7027, a planetary nebula located 2,900 light-years away.
Molecule Manhunt
The discovery sheds new light on the behavior of planetary nebulas, as well as this particular chemical. It also provides researchers with better numbers, allowing them to develop more accurate hypotheses and models.
But, ultimately, this is a symbolic success, validating some of the most fundamental ideas we have about the early cosmos, which occurred 14 billion years ago.
According to the study’s authors, “the chemistry of the universe began with this ion.” Astronomy has struggled with the dearth of conclusive proof for its presence in interstellar space. The unequivocal finding disclosed here brings a decades-long quest to a successful conclusion.”
