Two New Mexico Tech astronomers played a key role in the international effort to assess an asteroid that briefly raised fears of a devastating impact on Earth, New Mexico Tech says. William Ryan, senior astronomer, and Eileen Ryan, director of the Magdalena Ridge Observatory’s 2.4-meter telescope, appear in NASA’s new documentary “Planetary Defenders: This Is Not an Exercise,” about the tracking of asteroid 2024 YR4.
The asteroid was discovered Dec. 25, 2024. On Jan. 27, 2025, its estimated chance of hitting Earth in 2032 passed 1.2%, and it later peaked at about 3.1%. Astronomers had only a few months to observe it before it moved out of view until 2028.
Led by William Ryan, the team used the observatory’s telescope near Socorro from January through March 2025 to measure the asteroid’s position and characteristics, even though it was extremely faint, about magnitude 24. “The Magdalena 2.4-meter telescope is one of the largest in NASA’s Planetary Defense network,” Eileen Ryan said.
Combined with data from Arizona’s Lowell Discovery Telescope and others, the measurements cut the impact odds to 1.5% on Feb. 19 and 0.27% the next day. By April 1, astronomers had ruled out an impact in 2032.
Why It Matters
Early impact odds can rise or fall quickly, and ground-based telescopes like New Mexico's are how scientists pin down whether an asteroid is actually a threat.
Editor’s note: Updated Nov. 1, 2026. This story was revised to cite the New Mexico Tech news story it is based on. Learn how Brant.One reports in our editorial standards.
