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‘Neutrino Hunters’ by Ray Jayawardhana

The tiny, barely detectable particles responsible for some of the galaxy's biggest explosions are the stars of astrophysicist Ray Jayawardhana's new book.

Neutrinos, which are released during the fusion reactions that power stars and in great floods when stars explode, are so light they were once believed to be weightless and so fast they were thought to outpace the speed of light (although scientists have since revised those estimates to just above weightlessness and just below light speed, respectively).

They are the infinitesimal Supermen of the universe: small enough to pass through the earth unhindered "like bullets cutting through fog," as Jayawardhana puts it, but powerful enough to play a pivotal role in the eruption of supernovae.


In this concise history, non-experts get a fascinating glimpse inside the labs and through the telescopes of the scientists whose research on neutrinos has shattered some of the prevailing theories in cosmology, physics, and even geology. While some of the science flies over the head of the layperson who learned everything she knows about astrophysics from Geordi La Forge of the Starship Enterprise, most of it is simplified enough to give the average reader a fighting chance.

And there's enough narrative to keep us hooked, delivered as scenes set in icy underground laboratories with names like SNOLAB, where researchers scan Olympic-size pools or cavernous geodesic domes for the ethereal flickers of blue light that signal the passage of a neutrino.

Like good science fiction, the book features zany geniuses and at least one seemingly mad scientist: the cripplingly shy Ettore Majorana, who developed a groundbreaking theory about the nature of neutrinos and then vanished mysteriously in 1938, possibly by jumping to his death in the Mediterranean Sea or disappearing into obscurity in Argentina.

The storyline traces the arc of neutrino research from the early 20th century through the modern era, beginning in 1930, when a disciple of Einstein's, Wolfgang Pauli, first proposes that an unseen particle might explain why radioactive decay does not seem to be following the law of energy conservation.


Acknowledging that his theory is a "desperate remedy" to preserve the integrity of the law, Pauli argues that the particle could be sneaking off with some of the reaction's energy. It takes another quarter century for scientists to conclusively detect neutrinos and prove Pauli right.

The book concludes with a look ahead at the practical applications of tracking these minuscule particles. Neutrino detectors are helping astronomers to better understand the life cycle of stars and could one day help them identify the dark matter they've hypothesized to account for missing chunks of the universe.

Neutrino science may also hold the key for particle physicists who have long puzzled over the mystery of the universe's creation. After the Big Bang, they believe, matter and antimatter should have been created in equal amounts, canceling each other out, leaving only a sea of radiation. If neutrinos tipped the balance in favor of matter, we owe them a debt of gratitude for planets, stars, and our own existence.

On our planet, Jayawardhana tells us, neutrino detectors could be used for surveillance to prevent nuclear proliferation, since illicit nuclear operations create bursts of neutrinos that would be impossible to conceal. Turned inward to the earth's core, they may assist geologists in modeling the planet's interior and understanding plate tectonics.


Of commercial interest, they could be used to find oil or mineral deposits. And scientists are tinkering with neutrino beams for long-distance communication, since they can travel unfettered through the earth without satellites or cables.

Jayawardhana's enthusiasm for his subject is infectious. Like one of the scientists he profiles, he too seems to have caught what he calls "neutrino fever." His voice is lively and endearingly nerdy, as when he reveals that neutrinos can change type spontaneously, and explains, "We use the whimsical term 'flavors' to describe the three neutrino types."

Discussing the ways neutrinos interact with the cosmos, Jayawardhana quotes an MIT researcher with a clear case of neutrino fever: "Whenever anything cool happens in the universe, neutrinos are usually involved." The reader comes away grasping, if not the full extent of astrophysics, then at least some of what makes it cool.

Jennifer Latson is writing a narrative nonfiction book about a genetic disorder called Williams syndrome, which makes people socially uninhibited and indiscriminately friendly. She tweets at @JennieLatson.