The Motherhood Diary

Lucy data reveals an asteroid with an unusual wobble

The Motherhood Diary Source: NASA (opens in a new tab)

An analysis of the Donaldjohanson flyby found a complicated rotation and clues to the asteroid's past.

Dated news brief · June 18, 2026

The Milky Way stretches across a star-filled night sky. Illustrative photograph, not an image of the specific event or discovery reported.
Illustrative photograph, not an image of the specific event or discovery reported. Photo: Nathan Anderson / Unsplash.

NASA reported findings from Lucy's April 2025 encounter with the asteroid Donaldjohanson. Observations revealed a peanut-like shape and a more complicated motion than a simple spin around one axis.

Images showed craters and ridges, while instruments offered evidence about the surface. NASA described iron-rich clays as a sign that liquid water had briefly been present in the distant past, not that water flows there now.

The analysis considered how solar heating could gradually change the asteroid's rotation and shape. The encounter also provided practice for Lucy's main work at Jupiter's Trojan asteroids.

The question behind the picture

Show an official image and ask what a photograph can reveal, then what might need another instrument. Shape is visible; composition requires different evidence. A striking picture may be just one part of an investigation, with further clues coming from measurements we cannot see directly.

Read NASA's report.

Illustrative photograph, not an image of the specific event or discovery reported. Photo: Nathan Anderson / Unsplash.

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