Thursday , January 28 2021

Astronomers have noticed the first molecule of the universe Science



William B. Latter (Science Center SIRTF / Caltech); NASA / ESA

By Daniel Cleary

The first molecule of the universe, thought to have been created after the great wave, was discovered in space for the first time. Helium Hydride (HeH), a combination of helium and hydrogen, was detected about 3000 light-years from Earth by the instrument of the Stratospheric Infrared Astronomy Astronomy Observatory (SOFIA), a telescope built in a converted 747 aircraft that flies over the opaque parts of the Earth's atmosphere.

HeH has long been thought to mark the "dawn of chemistry," since the remains of the big shake cool down to about 4,000 K and the ions began to associate with electrons to form neutral atoms. The researchers believe that in this primordial gas, the neutral helium reacted with hydrogen ions to form the first chemical bond that connects to the first molecule.

In 1925, chemists synthesized HeH in the laboratory. In the 1970s, theorists predict that the molecule may exist today, most likely re-formed in planetary nebulae, clouds of gas emitted by dying stars similar to the stars. But decades of observations failed to find any, singling out doubts in theory.

To find the elusive molecule, astrochemicals require characteristic frequencies of the light it emits, in particular the spectral line of the far infrared, which is usually blocked by the Earth's atmosphere. But SOFIA's infrared spectrometer allowed them to find that signature for the first time in a planetary nebula called the NGC 7027 (in the picture above), researchers today Nature. The result shows this incredible molecule that includes typically unreactive helium – can be created in space. With the cornerstone confirmed, it seems that the evolution of the next 13 billion years of chemistry stands on a firm basis.


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