Carl Grillmair, an astronomer at Caltech's IPAC science and data center for astronomy and planetary science, passed away suddenly on February 16, 2026. He was 67 years old. Grillmair's science interests spanned many topics, such as exoplanets and stellar streams, which are remnants from ancient collisions between our Milky Way and other galaxies. He discovered dozens of these streams, with many named by him. In 2007, in one of his most impactful findings, he was lead author on a publication