The principle at the heart of chemical kinetics is that as you heat a reaction up, it goes faster. This is because the molecules have more energy to overcome potential energy barriers. However, scientists at the University of Leeds in the UK, have shown that the reaction between the hydroxyl radical and methanol is quick even at 63K (–210°C). In fact, the reaction is faster at this chilly temperature than at 200K.

The reason for this counter intuitive result is quantum tunnelling, which allows the molecules to travel across a potential energy surface despite classical mechanics predicting that they don’t have enough energy to make the journey. As the latest example of the growing importance of ‘tunnelling control’, Dwayne Heard’s group suggest that interstellar dust clouds might be host to more chemistry than previously imagined.