The presence of organic molecules in interstellar space has long been known, cosmic dust, cometary tails and other heavenly detritus reveal the presence of small, and occasionally not so small, molecules through the spectroscopic signatures of starlight on its journey to Earth and radio astronomy.
Wikipedia maintains a fascinating list of the molecules that have been found so far among them methane, acetylene, isocyanic acid, formamide, acrylonitrile, ethanimine, buckminsterfullerene, anthracene, and, of course, methanol. Dwayne Heard, Professor of Atmospheric Chemistry, at the University of Leeds recently alerted me to some intriguing work his team has carried out following the observation by radio astronomy in 2012 of the methoxy (CH3O) radical. He and his colleagues have shown how one reaction - formation of that radical from methanol and hydroxyl radicals - that would seemingly be impossible at the rather chilly -210 Celsius of outer space can occur at fifty times the rate it occurs at room temperature here on Earth.
"The rate constants we have measured at very low temperatures typical of these [stellar] environments adds to the database for astrochemical 'chemical networks' which describes the chemical pathways and we have shown that there is a class of reaction which has not been considered before (OH reacting with oxygenated organics)," Heard told me. The reason it was not previously considered was that the barrier to reaction was thought to make any rate of reaction too small at low temperatures," he adds. "Tunneling changes that."
Reactions for which the energy barrier is as high as to make them impossibly slow can nevertheless occur quickly because of quantum mechanics. Even at the low temperatures anticipated as making almost any reaction as to be so sluggish as to realistically never proceed, tunneling allows the starting materials to dig their way through the energy barrier and emerge on the other side as a new chemical structure. Intriguingly, quantum tunneling in this form only becomes manifest when the normal reaction "over the barrier" is too slow as there is not enough energy. In the present case a complex that forms between OH and methanol is only sufficiently long-lived for tunneling to occur within it at low temperatures.
The team carried out their studies using high-speed gas jets cooled to -210 Celsius. Collimation keeps the starting materials away from the walls so that they will not condense on the container or pipework. Of course, low-temperature techniques as well as the revelation of how quantum mechanics is involved in the chemistry of the cosmos, might trickle down into more terrestrial domains such as understanding the role of free radicals in atmospheric chemistry, pollution and the formation of novel materials, such as radical-driven polymer reactions.
Heard et al., Nature Chem, 2013, online DOI: 10.1038/NCHEM.1692
David Bradley blogs at http://www.sciencebase.com and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".