Liam Graham (Springer Link)
UNLIKE quantum or particle physics, thermodynamics rarely makes headlines, yet it is crucial for understanding how life arose and how the universe containing that life will end. This is at the heart of Molecular Storms: The physics of stars, cells and the origin of life by physicist-turned-economist Liam Graham.
His grand tour of the physical world leaves little unexamined, starting with simple systems of gas molecules in a box, moving to the smallest, simplest living cells, then on to whole planets. Graham does a stunning job of connecting everything to the state of disorder we call entropy and to the driving force behind structures everywhere 鈥� the 鈥渕olecular storms鈥� of his title.
Advertisement
He offers a more precise definition of entropy in terms of the microscopic states that a system can support given its macroscopic constraints 鈥� such as how the arrangement of water molecules in a glass of water are constrained by the shape and volume of the glass. Thanks to molecular storms, the system fluctuates between states. And at the level of nature鈥檚 smallest building blocks, everything is constantly pushed around by those storms.
Then there is the second law of thermodynamics: entropy in an isolated system can increase, but can never decrease. Graham emphasises that, while this law can be derived from statistics rather than from forces or other familiar concepts in physics, it still underlies so much of the phenomena around us.
His book can get challenging for readers of popular science, but it teaches them to ask how everyday objects contribute to the entropy of the universe. Take what happens when you remove the plug after a bath. Though the violent swirl produced 鈥� a vortex 鈥� may not seem like it, a careful accounting of all possible arrangements of water molecules in the bath shows it is an unexpectedly low-entropy structure.
And what about the 鈥渘anomachines鈥� copying DNA inside your cells? They create information-rich, specific molecules 鈥� surely they must be working to decrease entropy? Unravelling the puzzle of the complex mechanisms that keep them from breaking the second law explains their very nature.
Molecular Storms ends by discussing life鈥檚 origins, adding in all its complications, ones that wouldn鈥檛 work if they couldn鈥檛 somehow, sometimes, decrease local entropy in at least some parts of a vastly disordered universe. While much remains open, Graham is certain of one thing: we need thermodynamics to make sense of the world鈥檚 wild complexities.
