Space : astronomers discover the molecule from the origin of the universe

Mindy Sparks
April 20, 2019

Despite its unquestioned importance in the history of the early Universe, the HeH+ molecule has so far escaped detection in interstellar space, researchers said.

For many years, HeH+, the helium hydride ion, was thought to be the first molecule formed after the Big Bang's aftermath, however, no one could detect its whereabouts. As those dying stars cool, they still radiate enough heat to strip nearby hydrogen atoms of their electrons, turning the atoms into the bare protons that are required for HeH+ to form.

Scientists have detected the most ancient type of molecule in our universe in space for the first time ever. That molecule should be present in some parts of the modern universe, but it had been undetected in space.

However, Earth's atmosphere is opaque at this wavelength for ground-based observatories, requiring this search to be performed from space or a high-flying observatory like SOFIA cruising above the absorbing layers of the lower atmosphere. It had looked for decades after the helium hydride ion.

"This particle was lurking out there, yet we needed the right instruments making observations in the correct position - and SOFIA had the capacity to do that impeccably", Harold Yorke, director of the SOFIA Science Center, said in an announcement. It makes sense those first molecules would be helium hydride, and it would have been essential in the formation of the first stars. "This brings a long search to a happy ending and eliminates doubts about our understanding of the underlying chemistry of the early universe".

But mostly, this is a symbolic victory, confirming some of the most basic things we think we know about the early universe, some 14 billion years ago. Since the 1970s, scientists have been trying to fish it out in NGC 7027, where they believed it could exist.


Deployed from a modified Boeing 747SP jetliner, the SOFIA team explains that their system is highly customisable and can be tailored with new equipment all the time, thanks to the observatory returning from flights frequently.

Now experts say they have finally spotted helium hydride in a small but bright 600-year-old planetary nebula about 3,000 light years away in the constellation of Cygnus. That all changed when SOFIA received the GREAT (German Receive at Terahertz Frequencies) upgrade, allowing it to pinpoint the molecule in the nebula's soup just like any sane person would pluck peas out of their minestrone.

Despite attempts to detect HeH+, finding its signal can be a hard process, since the opaqueness of Earth's atmosphere makes it challenging for ground-based observatories to pick up activity.

Looking into the planetary nebula 40 years ago, astronomers thought they might find traces of the molecule, but the dense chemical soup made it hard to pin down.

As Engadget points out, this discovery also showcases the capabilities of the technology afforded to NASA, with their SOFIA project being the largest airborne observatory in the world.

Other reports by Iphone Fresh

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