Scientists have discovered evidence of the earliest chemistry in the universe thanks to measurements from a telescope aboard a modified Boeing 747.
After the big bang, the universe began to cool, and atoms like hydrogen, helium and lithium began to form out of the free particles. When the entire universe reached a temperature of a few thousand degrees, these atoms should have begun to bind each other (otherwise we would not exist), and the physics theory suggests that the first bond would have been a helium atom bound to a hydrogen atom. But the resulting helium hydride has never been found in space so far thanks to the Stratospheric Observatory for infrared astronomy or SOFIA.
"This was predicted 30 to 40 years ago by early chemical models,"
The study's first author, Rolf Güsten from the Max Planck Institute for Radio Astronomy, told Gizmodo.
Scientists first had to verify that the universe could create such a molecule at all. Scientists in the 1970s theorized that nearby plasma in planetary nebulae, dying stars surrounded by ejected material, may contain helium hydride. But scientists have faced challenges that detect the molecule and question whether the molecule exists in space at all, according to the paper published today in Nature.
"Until recently, there was no technology to do so," Güsten explained. The wavelengths of the signature of light emitted by the molecule would be absorbed by the Earth's atmosphere.
Geoffrey Blake, a professor of engineering college in California who was not involved in the study, told Gizmodo that scientists had stopped looking for the molecule in the early universe – which meant the very distant universe – because they couldn't even find it nearby.
But now, NASA and the German Aerospace Center (DLR) have a custom Boeing 747, SOFIA, ready to perform the search.
SOFIA flies at 38,000 to 45,000 feet, according to a NASA fact sheet, which is over 99 percent of the infrared absorbent parts of the atmosphere. The researchers deployed an instrument on SOFIA called the German recipient of astronomy at Terahertz frequencies (GREAT) and pointed it to the planet nebula NGC 7027, known to offer researchers a number of other astrochemical findings. After three flights in May 2016 and some data analysis, the work revealed the presence of helium hydride molecules in the nail.
These results showed to researchers that the universe really could form the molecule on its own, and has improved astronomers' understanding of the earliest eras after the Big Bang. It's a big deal.
"I would say that this is probably the most important discovery made by the SOFIA Observatory," Mike Barlow, a professor at the London College who was not involved in the research and reviewed the paper, told Gizmodo. He found the data convincing.
So no, they did not discover the exact earliest helium hydride, but now researchers may perhaps go back to hunting for the signature from longer sources, Blake says. And it's nice to know that research on the origin of chemistry has gone the right way. It is even colder that the research is done aboard one of the least conventional telescopes around.