May 29, 2020

Review: The Cosmic Cocktail by Katherine Freese

A stellar recipe!

It’s the hottest topic in modern astrophysics. What exactly is dark matter and dark energy? It is kind of amazing to think that astrophysicists do not yet completely understand just what most of the universe is made of.

And author Katherine Freese is on the forefront of this hunt, as she relates in her new book, The Cosmic Cocktail: Three Parts Dark Matter out from Princeton Press. Freese is the George E. Uhlenbeck Professor of Physics at the University of Michigan and has been involved with the hunt for the missing mass of the universe. The Cosmic Cocktail follows the history of the hunt, through to modern efforts and where the field of 21st astrophysics might be headed.

But The Cosmic Cocktail also outlines the author’s personal journey through the world of modern physics as well. The Cosmic Cocktail reads like a good science mystery, with the “whodunit” party as yet to be named. It was astronomer Fritz Zwicky who first coined the term “dark matter” in 1933, and the hunt for it has become THE name of the game in modern astronomy.

And the really exciting news is, much like the announcement of the discovery of the Higgs-Boson in 2012, we may be finally closing in on the nature of dark matter. One common misconception put to rest in the book is how a majority of the universe can turn up missing. We see this fallacy touted lots in the pseudoscience world: if scientists don’t even know what constitutes most of the cosmos, how can they be sure of anything?  The author lays out compelling reasons for why we know dark matter has to exist, such as the motion of stars in the Bullet Cluster. This is great science at its best, a quest to verify observations that match predictions.

The Cosmic Cocktail also traces the various ideas for dark matter that have been proposed and subsequently disregarded on the cutting room floor of physics over the years. Two basic ideas that have emerged in the late 20th century as to the nature of dark matter are known as MACHOs (Massive Compact Halo Objects) and WIMPs (Weakly Interacting Massive Particles). Candidates for MACHOs have included such cosmically pedestrian objects as black holes, white dwarfs and other debris populating the galactic halo. However, efforts to observe gravitational lensing events from such objects show that the amount of mass “out there” falls far short of the required amount needed to create the gravitational effects observed.

Despite their weakling moniker, WIMPs appear to be winning the day in the minds of astrophysicists. One such suspect may be the neutrino, a bizarre particle that permeates space in droves. Most neutrinos pass right through the Earth as if it’s not even there, only very occasionally interacting with a particle of baryonic matter for scientists to observe. And even more exotic ideas for dark matter candidates have been proposed… its strange to think, dark matter could surround and permeate all of us, vastly outnumbering the number of “ordinary” particles” but only begrudgingly interacting with it.

Strange but exciting stuff, to be sure. Check out The Cosmic Cocktail to get an exciting look at the forefront of astrophysics!



  1. [...] We first heard of the Soudan Underground Laboratory while reviewing Katherine Freese’s new book The Cosmic Cocktail. [...]

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