Telling the earth's story

How the Earth’s climate has changed over time is a big story, but interestingly, a critical part of this story is encoded in something extraordinarily small: the layers of minerals that build up around grains of sand as they roll back and forth in shallow seawater over thousands of years. This minuscule “mineral archive” is the focus of geochemist Dr. Nir Galili, the newest member of the Weizmann Institute’s Department of Earth and Planetary Sciences.

“In my work, I examine how minerals preserve information about temperature and other climate‑related dynamics,” says Dr. Galili, adding that he was first introduced to this topic while pursuing his doctorate at the Weizmann Institute under Prof. Itay Halevy. “In ancient times, the Earth’s oceans could reach temperatures higher than 100 degrees centigrade. In my PhD research, I used chemical methods to examine the iron oxide―rust―in rock samples gathered from where the ocean used to be. The oxygen isotopes we identified allowed us to measure ocean temperatures at the time the rust formed.”

During a four-year postdoctoral fellowship at ETH Zürich in Switzerland, Dr. Galili continued to investigate how rock‑encased minerals could help scientists establish a timeline for changes in ocean temperature. Soon, however, he began to wonder if one category of his samples could reveal even more.

“The rocks we studied were packed with ooids, tiny bead-shaped structures that, when split open and examined under the microscope, are shown to be made up of multicolored mineral layers that formed around a single grain of sand over a long period of time,” he explains, adding that he had a hunch the oxygen isotopes trapped in these layers might also shed light on how much carbon was sequestered in the ocean during different historical eras.

“The carbon dissolved in the ocean exists in balance with carbon in the atmosphere, including CO₂, a greenhouse gas associated with climate change,” he says. “If our experiments were successful, it would establish ooids as a new—and very beautiful—model for studying ancient climate patterns.”

The prestigious journal Nature recently reported that Dr. Galili and his team at ETH were indeed successful. “By characterizing the oxygen isotopes present in natural ooids, and by comparing this data with ooids synthesized in the lab, we created a paleoclimate proxy―a mechanism for identifying climate conditions prevalent at specific points in the very distant past. This is a completely new approach that could help us answer some very big questions about climate evolution.”

Every setback is an opportunity

Dr. Galili was wrapping up his postdoc and preparing for his return to Rehovot when two Iranian missiles slammed into the Weizmann Institute in June 2025. Two buildings took direct hits, and many others sustained tremendous damage, including the Sussman Family Building for Environmental Sciences, where he was slated to open his new lab.

“Some of our infrastructure was up and running when the missiles hit, and some equipment essential to our work was completely destroyed,” he says. Thankful for the immediate support of faculty colleagues who shared their workspace and resources, he also points out that in science, every setback is an opportunity.

“Getting back on track will take time, but in science, you play the long game. Five years from now, I know I’ll be grateful for the time I have today to explore new scientific questions, and hopefully, overcome exciting new challenges.”

Podcasting journey

Outside of the lab, Dr. Galili hosts a family-friendly podcast together with his young children. Called Journey to the Center of the Earth, it aims to introduce the next generation to the wonders of Earth science. Inspired by Dr. Galili’s passion for science education, the venture also served to strengthen his ex‑pat kids’ Hebrew language skills.

“We were abroad for four years during my postdoc, and I didn’t want our children to forget their Hebrew,” he says, adding that the podcast was his oldest daughter’s idea, and that an English version of the podcast is planned.

“Giving my seven‑year‑old and my four‑year‑old the microphone and having a conversation about science, we produced a podcast that reflects how kids understand the world. Sure, it requires a few more ‘takes’ than it would if I had been interviewing an adult, but the results are worth it!”

EDUCATION AND SELECT AWARDS
• BSc, magna cum laude, Ben-Gurion University of the Negev (2011)
• MSc (2016), PhD (2021), Weizmann Institute of Science
• Postdoctoral Fellow, ETH Zürich (2022-2025)
• Peretz-Grader Award for Young Researchers from the Israel Geological Society (2020), Prof. Israel Dostrovsky Prize of Excellence from the Weizmann Institute and the Israel Atomic Energy Commission (2021), ETH Zürich Career Seed Award (2023)