San Marcos

Physics Professor Helps Unlock Puzzle of the Origin of Water on Asteroid Surfaces



​​The question has vexed astronomers for years: how do water and hydroxyl radicals, which have the same elements as water, surface on asteroids sluicing through space? A paper co-published by Cal State San Marcos physics professor Dr. Gerardo Dominguez in October in the peer-reviewed scientific journal Nature Astronomy provides the answer.

“Regenerative Water Sources on Surfaces of Airless Bodies” paper concludes that two primary mechanisms are the source of surface water—low-temperature oxidation of organics, and mineral dehydration—and they are transformed through the impact of micrometeorites and the heat pulses they generate during an asteroid’s travels.

“Any mechanisms that are discovered that generate water on asteroids are fascinating and help us better understand what is happening in the universe,” Dr. Dominguez said. “This helps answer a puzzle as to where this water on asteroid surfaces comes from.” 

Dominguez was unaware of the study until the principal investigator, professor Ralf I. Kaiser, contacted him. Dr. Kaiser and his team at the University of Hawaii had submitted their research to Nature Astronomy, but reviewers were skeptical that the duration of laser pulses mentioned in the experiments, which were aimed at mimicking the heat pulses caused by micrometeorite impacts on asteroid surfaces, were correct. Kaiser came across Dominguez’s earlier research on micrometeorite impacts into on solids and asked the CSUSM professor to provide theoretical modeling on the amount of heat and the duration of heat-pulses generated by micrometeorite impacts to convince Nature Astronomy’s peer reviewers.

Mission accomplished.

In fact, Dominguez’s research long has been aimed at unlocking the secrets of the universe. His work has earned him recognition from the National Academy of Sciences, NASA and the newsmagazine Diverse: Issues in Higher Education as a top researcher in planetary astrophysics and atmospheric chemistry. Continuing research includes exploring the isotopic composition of molecular clouds to understand how the sun and the planets of our solar system were formed. Dominguez also has conducted extensive research in the application of nano-optical techniques for mapping the chemical composition of meteorites and cometary dust grains. 

This past summer, a CSUSM team led by Dominguez was one of eight research teams from around the country awarded a $10.5 million NASA grant to study the origins of ice on the moon. 

Not bad for a first-generation American and self-described nerd from San Pedro who grew up devouring books about how things worked.

“How the universe works, how atoms work, it all just fascinated me as a kid,” he said. 

Dominguez earned his bachelor’s degree, master’s degree and doctorate in physics from UC Berkeley. He has been teaching at CSUSM since 2011.