Alcohol formation in space was thought to be nearly impossible, due to the low temperatures present far from stars. Chemical reactions speed up as temperatures increase, and it was believed that the incredibly cold temperatures in space would slow alcohol formation to a near-halt. Astronomers, however, have long seen vast amounts of alcohol in gaseous formations in the depths of space. This presented a great puzzle in astronomy and chemistry which may have just been solved.
The bizarre process known as quantum tunneling may explain how giant clouds of alcohol form, in the vast depths of space. Quantum tunneling occurs in the smallest of scales, allowing subatomic particles the ability to pass from one location to another, without traversing the space between the two. This could allow subatomic particles to get close enough to each to form bonds, despite being repelled from each other by electromagnetic forces.
Recreating the environment of deep space in their laboratory, researchers were able to create methoxy radicals from a mixture of methanol and hydroxyl radicals, an oxidizing agent 50 times faster at -347 degrees Fahrenheit than at 70 degrees.
"The answer lies in quantum mechanics. Chemical reactions get slower as temperatures decrease, as there is less energy to get over the 'reaction barrier'. But quantum mechanics tells us that it is possible to cheat and dig through this barrier instead of going over it. This is called quantum tunneling," Dwayne Heard, of the University of Leeds, who led the research, said.
One of the earlier theories to explain the formation of alcohol in temperatures thought to be too cold for chemical reactions to occur involved dust. It was believed that the oxygen and hydrogen atoms needed to form alcohol collected on dust, later combining together into molecules. In 2012, methoxy radicals were discovered in space which can not form through this process. This left chemists and astronomers without a viable process by which these alcohols could form.
"[W]e suggest that an 'intermediary product' forms in the first stage of the reaction, which can only survive long enough for quantum tunneling to occur at extremely cold temperatures," Heard said.
In order to not let the gases condense by hitting the sides of the container, Robin Shannon from the University of Leeds mixed the reactants in coordinated jets of gas, a technique first pioneered for the Saturn V rocket in the 1960's.
Research exploring the role played by quantum tunneling in the formation of alcohols in deep space were published in the journal Nature Chemistry.
