3 min readNew DelhiJun 26, 2026 09:26 AM IST
First published on: Jun 25, 2026 at 06:19 PM IST
Nasa‘s Lucy spacecraft has spotted an asteroid shaped, oddly, like a peanut which wobbles in space instead of smoothly spinning on a single axis.
The asteroid, named Donaldjohanson, also carries possible evidence of ancient water, making it important for understanding the mysterious early history of our solar system, according to Nasa’s website.
Lucy collected its first close-up images and data on Donaldjohanson on April 20, 2025, passing just 960 km from the asteroid, and a look at the data revealed that this asteroid has a two-axis rotation, unlike most asteroids and planets, which usually spin simply around a single axis.
Scientists also got their first clear look at the asteroid’s distinctive peanut shape, along with the craters and ridges covering its surface.
Traces of water
The spacecraft recorded the signatures of iron-rich clay minerals on the surface. Nasa scientists said these clays formed in the distant past, when liquid water was possibly present.
The scientists also pointed out that the iron in clays tends to get replaced by other elements, such as magnesium, when water is present for a long period of time.
This pattern was seen in two other asteroids – Bennu and Ryugu – where magnesium-rich clays were discovered, suggesting that these asteroids were exposed to water for an extended period, possibly lasting millions of years, back when they were still part of much larger parent bodies.
Why the asteroid slowed down
Donaldjohanson’s peculiar rotation is likely caused by a subtle effect of solar heating, which is known as the YORP effect.
As sunlight warms the asteroid’s surface, each part of it likely radiates heat back as infrared light. As a result, this radiation creates a tiny recoil force on the surface, and as the asteroid is not symmetrical in shape, the uneven forces add up to produce a net twist that can alter its rotation over time.
The YORP effect can either slow an asteroid’s spin down or speed it up.
About Nasa’s Lucy spacecraft
Lucy’s principal investigator is based at the Boulder, Colorado, branch of Southwest Research Institute, which is headquartered in San Antonio.
The spacecraft itself was built by Lockheed Martin Space in Littleton, Colorado.
Lucy is the 13th mission in Nasa’s Discovery Program, which is managed by the Marshall Space Flight Center in Huntsville, Alabama, on behalf of the agency’s Science Mission Directorate in Washington.
About asteroid Donaldjohanson
The asteroid is named after anthropologist Donald Johanson, who discovered the fossilised skeleton called “Lucy.”
Donaldjohanson was formed after a violent collision 155 million years ago, and is located in the main asteroid belt between Mars and Jupiter.
Lucy got a close look at asteroid Donaldjohanson as it made its way toward the Jupiter Trojan asteroids. The spacecraft passed within approximately 600 miles, or 960 kilometres, of the asteroid during the encounter.
(This article has been curated by Paramita Datta, who is an intern with The Indian Express)
Scientists also got their first clear look at the asteroid's distinctive peanut shape, along with the craters and ridges covering its surface.
(Screenshot/NASA official website) 
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