The Discovery of the Universe's First Molecule: A Breakthrough
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Chapter 1: The Historic Find
The molecule helium hydride, composed of hydrogen and helium, has long been theorized as the first to form in the Universe. Researchers have finally uncovered evidence of its existence in a distant planetary nebula after decades of searching. This marks a significant milestone in our understanding of cosmic chemistry.
Just 100,000 years following the Big Bang, hydrogen and helium fused to create helium hydride (HeH+). Although scientists believed this molecule should still be observable in the cosmos, this discovery represents the first time it has been identified in the contemporary Universe. This finding not only verifies that helium hydride can exist in space but also supports theories regarding the chemical processes during the Universe's earliest moments.
“This moment was incredibly thrilling. Observing helium hydride in our data brought closure to a long quest and reinforced our confidence in the chemistry of the early Universe,” remarked Rolf Guesten from the Max Planck Institute for Radio Astronomy.
Section 1.1: The Birth of Chemistry
After the Big Bang, the Universe cooled, leading to the formation of hydrogen and helium as the primary elements, along with trace amounts of lithium. In today's context, helium is regarded as a noble gas, largely unreactive except under specific laboratory conditions. However, physicists have long theorized that during the Universe's formative era, helium could combine with a hydrogen ion, thus producing helium hydride, the first molecule ever created.
Captain Janeway: “Omega caused quite a stir among my own species. Federation cosmologists had a theory that the molecule once existed in nature for an infinitesimal period of time at the exact moment of the Big Bang. Some claimed Omega was the primal source of energy for the explosion that began our universe.”
Seven of Nine: “A creation myth like any other.”
- Star Trek: Voyager “The Omega Directive”
David Neufeld, a professor at Johns Hopkins University, stated, “The formation of HeH+ was the initial step towards increasing complexity in the Universe.”
Section 1.2: The Role of SOFIA
The Stratospheric Observatory for Infrared Astronomy (SOFIA), the largest airborne observatory in the world, successfully detected this elusive molecule in the remnants of a dying star, specifically in the planetary nebula NGC 7027, located 3,000 light-years from Earth within the Milky Way.
In the 1970s, astronomers confirmed that NGC 7027 had the right conditions for the formation of helium hydride. This young, hot star expelled a shell of gas just 600 years ago (as viewed from Earth), creating an environment conducive to the emergence of this ancient molecule.
Detecting HeH+ in space poses a challenge because it emits electromagnetic waves in far-infrared wavelengths, which are obstructed by Earth's atmosphere, rendering them invisible to ground-based observatories.
“This molecule was hidden out there, but we required the proper instruments positioned correctly — and SOFIA was perfectly suited for that,” noted Harold Yorke, director of the SOFIA Science Center.
Over three nights in May 2016, a Boeing 747 equipped with a 2.7-meter (107-inch) telescope and an infrared spectrometer soared to an altitude of 14,000 meters (45,000 feet) to search for this rare molecule. Astronomers utilized the German Receiver at Terahertz Frequencies (GREAT) instrument, a recent addition to SOFIA, allowing them to observe the wavelengths produced by helium hydride.
Chapter 2: Understanding Helium Hydride
Helium hydride formed when the Universe cooled to around 4,000 degrees Kelvin (6,700 degrees Fahrenheit). Shortly after, the creation of HeH+ ceased as stars began synthesizing heavier elements. As the Universe continued its cooling process, more complex molecules began to populate the cosmos.
“As recombination progressed, the destruction of HeH+ facilitated the formation of molecular hydrogen. Despite its undeniable significance in the early Universe’s evolution, the HeH+ ion had previously evaded definitive detection in interstellar space,” researchers explained in a journal article in Nature detailing the discovery.
Notably, helium hydride was first synthesized in a laboratory in 1925 and is recognized as the strongest acid known to humanity. The early days of the Universe now feel closer to us than ever.