L&S astronomy alum Kareem El-Badry awarded 2025 MacArthur 'genius' fellowship

Photo of Kareem El-Badry

Credit: John D. and Catherine T. MacArthur Foundation

October 8, 2025
Lauren Miller

Astrophysicist Kareem El-Badry, an alumnus of the UC Berkeley College of Letters & Science (M.S. '18, Ph.D. '21, Astronomy), has been awarded a 2025 MacArthur Fellowship. The new MacArthur Fellows class, which was named on Wednesday, October 8, was rounded out by 21 other exceptional individuals, including UC Berkeley associate professor of optometry and vision science Teresa Puthussery, Engineering alum William Tarpeh (Ph.D. '17, Environmental Engineering) and Fall 2019 On the Same Page featured author Tommy Orange (There There).

MacArthur Fellowships, often called "genius grants," provide each recipient with an $800,000 stipend, a "no-strings-attached award to extraordinarily talented and creative individuals as an investment in their potential," according to the MacArthur Foundation website. 

“The 2025 MacArthur Fellows expand the boundaries of knowledge, artistry, and human understanding," shared Kristen Mack, Vice President of Communications, MacArthur Fellows, and Partnerships, on the program website. "They focus our attention on microbial worlds and distant stars, community vitality and timeless traditions, sacred and improvisational music, and shared histories of our time on Earth. With virtuosity, persistence, and courage, they chart new paths toward collaborative, creative, and flourishing futures.”

The College of Letters & Science is pleased to congratulate Kareem El-Badry on his outstanding accomplishment. 

Kareem El-Badry shared the following reflection on his experience as a Ph.D. student in the astronomy department in the UC Berkeley College of Letters & Science:

[All] the different search strategies I tried during my thesis were crucial for developing and refining the method, and the different methods I developed for combing through large datasets in search of needles in haystacks are ultimately what I’m being recognized for with the MacArthur prize.
Kareem El-Badry (M.S. '18, Ph.D. '21, Astronomy)

"I had a fantastic time as a PhD student in the Berkeley astronomy department, and the many different kinds of projects I was able to try during grad school really got my career going. I started grad school as a theorist working on simulations of galaxy formation, and in my qualification exam, I pitched a project that was all about galaxy formation simulations. As it turned out, right after my qualification exam, I got excited by data from the Gaia satellite — which I learned about through conversations with several excellent faculty and visitors in the astronomy department — and completely changed my thesis plan, to an observational project focused on binary stars and black holes. Fortunately, Berkeley does not have a thesis defense, so no one ever questioned what happened to the galaxy formation plan I laid out in my qualification exam! 

I spent most of the last two years of my PhD on a project looking for stellar-mass black holes orbited by normal stars. I tried all kinds of different search methods, but none of them worked! It took me another year, until the 3rd Gaia data release during my postdoc, to actually find one, which ended up being the nearest known black hole to Earth. But all the different search strategies I tried during my thesis were crucial for developing and refining the method, and the different methods I developed for combing through large datasets in search of needles in haystacks are ultimately what I’m being recognized for with the MacArthur prize."

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