NASA's Lucy Spacecraft Reveals 155-Million-Year Story

NASA's Lucy spacecraft just decoded the entire history of a distant asteroid during a single 10-minute flyby, and the story it found is surprisingly dramatic.

On April 20, 2025, Lucy zipped past asteroid Donaldjohanson at just 600 miles away, snapping photos every two seconds. What those images revealed tells a cosmic tale of collision, slow-motion tumbling, and a neck that's reshaping itself right now.

The asteroid looks like a snowman, two rocky lobes stuck together at a narrow middle. Scientists led by Simone Marchi at the Southwest Research Institute counted craters across both lobes and found something fascinating: both chunks are at least 40 million years old, their surfaces so packed with impact marks that new craters now erase old ones.

The story gets better. That connecting neck between the lobes is much younger, less than 20 million years old, with a suspiciously smooth surface. How can the body parts be ancient while their connection stays youthful?

The answer is in the spin. Lucy measured Donaldjohanson rotating incredibly slowly, taking more than 10 days to complete one tumble. At that lazy pace, centrifugal force vanishes and gravity takes over, pulling loose rock and dust downhill toward the larger lobe.

Every time a space rock smacks into Donaldjohanson, the impact shakes material loose from the smaller lobe. That debris slides down the smooth slope toward the bigger side, constantly rebuilding and refreshing the neck region. It's like a cosmic landslide happening in super slow motion across millions of years.

Scientists traced the asteroid's family tree back 155 million years to a massive collision that destroyed its parent body. Two kilometer-sized fragments drifted together and stuck, initially spinning rapidly every few hours. Sunlight pressure gradually slowed that spin over tens of millions of years until gravity could reshape the surface.

Lucy's spectroscopic instruments even identified iron-rich clay minerals, confirming Donaldjohanson's membership in the Erigone asteroid family.

Why This Inspires

This flyby was just a practice run. Lucy gathered all this detail from a tiny, distant rock during a 10-minute encounter, proving the spacecraft's instruments work beautifully for future missions.

Next year, Lucy approaches Eurybates-Queta, an asteroid more than 10 times larger, where even more secrets wait to be revealed. We're learning to read the biographies written in space rocks, turning quick snapshots into epic geological novels spanning hundreds of millions of years.

The universe keeps better records than we ever imagined, and we're finally learning to read them.