NASA’s Lucy spacecraft recently uncovered surprising details about asteroid Donaldjohanson, a peanut-shaped object that spins in a complex, wobbling pattern and preserves evidence of ancient water. These findings shed light on the asteroid’s violent formation and gradual evolution under sunlight’s quiet influence.
- Asteroid formed from a violent collision about 155 million years ago
- Rotation influenced by the Sun’s subtle YORP effect, causing its slow wobble
- Surface minerals reveal signs of short-lived liquid water in the distant past
What happened
NASA’s Lucy spacecraft passed close to asteroid Donaldjohanson in April 2025, traveling through the main asteroid belt. The encounter allowed scientists to capture the first detailed images and data of this peanut-shaped asteroid, revealing its bilobate form composed of two lobes connected by a narrow neck. The asteroid was formed approximately 155 million years ago when fragments from a massive collision slowly came together under gravity.
Further observations showed that instead of a simple rotation, Donaldjohanson wobbles in an unusual manner, turning end-over-end every 10.5 days and rocking around its long axis every 26.5 days. This complex spin pattern was shaped over millions of years by the YORP effect, where sunlight exerts tiny but persistent torques on irregularly shaped objects, gradually altering their spin rates.
Why it feels good
This discovery offers a fascinating glimpse into the dynamic history of small bodies in our solar system. Understanding how asteroids like Donaldjohanson evolve helps scientists piece together the story of planetary formation and the forces at work over vast timescales. The wobbling motion adds a layer of complexity previously unappreciated in asteroid rotations, highlighting nature’s subtle balance of cosmic forces.
Moreover, the detection of iron-rich clay minerals on the asteroid’s surface suggests that water once flowed or existed briefly there. Although this water exposure was limited, the presence of these minerals opens exciting possibilities about how water—and potentially the ingredients for life—might have been distributed across space during the solar system’s infancy.
What to enjoy or watch next
Lucy’s successful flyby of Donaldjohanson served as an important rehearsal before it reaches its primary targets, the Jupiter Trojan asteroids, starting with the Eurybates encounter scheduled for August 12, 2027. Scientists are eager to compare Lucy’s findings at Donaldjohanson with data from Bennu and Ryugu, two other well-studied asteroids with sample-return missions.
Continued study of Lucy’s data will deepen our understanding of how sunlight and collisions evolve asteroids over millions of years. Stay tuned for more revelations as Lucy proceeds on its mission to unravel the mysteries of these ancient space travelers, potentially reshaping our views of solar system history.