The mandolinist Chris Thile, better known for his work with the bluegrass band Nickel Creek, and the novelist Junot Díaz, who won a Pulitzer for his novel The Brief and Wondrous Life of Oscar Wao, are among those awarded 2012 "genius" grants from the John D. and Catherine T. MacArthur Foundation.

The 23 MacArthur fellows will receive $500,000 over the next five years. They are allowed to do whatever they wish with the money, whether that's continue their work or change fields.

The 2012 honorees come from a wide-array of fields — they're historians and scientists and one of them is a stringed-instrument bow maker.

All Things Considered's Melissa Block spoke to geochemist Terry Plank, one of the recipients. She told Melissa that her entire life, she's been a geologist and that her ultimate goal is to get to the bottom of why some volcanoes have more violent eruptions than others.

"What I really want to put together is where the volcano starts," she said. So she studies the amount of water — which fuels eruptions — in volcanoes and she's almost at a point where she can put a theory together.

Melissa also spoke to Dylan C. Penningroth, a historian at Northwestern University. Penningroth told her that his work takes him to county courthouses in four states and the District of Columbia, where he combs through old archives trying to piece together the legal life of black African American slaves and their descendants.

His theory, he said, is that "mundane legal action" changed black America.

Full disclosure: This blogger is a fan of the work of both Díaz and Thile. One good place to start on Díaz is t he excerpt of his new book, This Is How You Lose Her, that NPR Books published.

NPR Music has an "artist page" for Thile, but perhaps more magical is a Tiny Desk performance recorded back in November of 2011. Here's Thile with fellow string players Yo-Yo Ma, Edgar Meyer and Stuart Duncan:

Here are the rest of the recipients and their biographies, according to the Associated Press:

Natalia Almada, 37, of Mexico City: "Documentary filmmaker who captures complex and nuanced views of Mexican history, politics and culture."

Uta Barth, 54, of Los Angeles: "Conceptual photographer who explores the nature of vision and the difference between seen reality and how a camera records it."

Claire Chase, 34, of Brooklyn: "Arts entrepreneur who engages audiences in the appreciation of contemporary classical music and opens new avenues of artistic expression through her International Contemporary Ensemble."

Raj Chetty, 33, of Cambridge: "Economist at Harvard University who studies how policy decisions affect real-world behavior."

Maria Chudnovsky, 35, of New York: "Mathematician at Columbia University whose work is deepening the connections between graph theory and other major branches of mathematics, such as linear programming and geometry."

Eric Coleman, 47, of Denver: "Geriatrician at University of Colorado School of Medicine who is improving health care by focusing on patient transitions from hospitals to homes and care facilities."

David Finkel, 56, of Washington, D.C.: "Washington Post journalist whose long-form newswriting has transformed readers' understanding of military service and sacrifice."

Olivier Guyon, 36 of Tucson, Arizona: "Optical physicist and astronomer at University of Arizona who designs telescopes and other astronomical instrumentation that play a critical role in the search for Earth-like planets outside this solar system."

Elissa Hallem, 34 of Los Angeles: "Neurobiologist at University of California, Los Angeles, who explores the physiology and behavioral consequences of odor detection in invertebrates and identifies interventions that may eventually reduce the scourge of parasitic infections in humans."

An-My Le, 52, of Annandale-on-Hudson, New York: "Photographer at Bard College who approaches the subjects of war and landscape from new perspectives to create images rich with layers of meaning."

Sarkis Mazmanian, 39, of Pasadena, Calif.: "Medical microbiologist at the California Institute of Technology who studies the role intestinal bacteria may play in a broad range of human diseases."

Dinaw Mengestu, 34, of Washington, D.C.: "Writer whose novels and nonfiction pieces enrich understanding of the little-explored world of the African diaspora in America."

Maurice Lim Miller, 66, of Oakland: "Social services innovator who designs projects that reward and track self-sufficiency among residents of low-income neighborhoods in Oakland, San Francisco and Boston."

Dylan C. Penningroth, 41, of Evanston, Illi.: "Historian at Northwestern University who is unearthing evidence from scattered archives to shed light on shifting concepts of property ownership and kinship among African American slaves and their descendants."

Terry Plank, 48, of New York: "Geochemist at Columbia University who probes the usually invisible but remarkably powerful thermal and chemical forces deep below the Earth's crust that drive the motion of tectonic plate collisions."

Laura Poitras, 48, of New York: "Documentary filmmaker revealing the consequences of military conflict abroad in documentaries that portray the lives and intimate experiences of families and communities largely inaccessible to the American media."

Nancy Rabalais, 62, Chauvin, La.: "Marine ecologist at the Louisiana Universities Marine Consortium who documents the environmental and economic consequences of dead zones in the Gulf of Mexico."

Benoit Rolland, 58, of Boston: "Stringed-instrument bow maker who experiments with new designs and materials to create violin, viola and cello bows that rival prized 19th century bows and meet the artistic demands of today's musicians."

Daniel Spielman, 42, of New Haven, Connecticut: "Computer scientist at Yale University who connects theoretical and applied computing to resolve issues in code optimization theory with real-world implications."

Melody Swartz, 43, of Lausanne, Switzerland: "Bioengineer who enhances understanding of the dynamic processes of tissue vascularization and immune responses to tumor invasion using concepts and methods from biophysics, cell culture, molecular genetics, engineering and immunology."

Benjamin Warf, 54, of Boston: "Pediatric neurosurgeon at Children's Hospital of Boston who is revolutionizing treatment of hydrocephalus and other intra-cranial diseases in young children and advancing standards of and access to health care in both the developed and poorest regions of the world."

Copyright 2016 NPR. To see more, visit http://www.npr.org/.