{"id":760172,"date":"2026-06-25T12:29:10","date_gmt":"2026-06-25T12:29:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/760172\/"},"modified":"2026-06-25T12:29:10","modified_gmt":"2026-06-25T12:29:10","slug":"peanut-shaped-asteroid-wobbles-in-2-directions","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/760172\/","title":{"rendered":"Peanut-shaped asteroid wobbles in 2 directions"},"content":{"rendered":"

\"AsteroidThis is asteroid Donaldjohanson<\/a>, as seen by NASA\u2019s Lucy<\/a> spacecraft during a flyby<\/a> on April 20, 2025. Its apparent rotation here is due to the spacecraft\u2019s motion as it flew by Donaldjohanson at a distance of 1,000 to 660 miles (1,600 to 1,060 km). But Lucy did find that this little asteroid wobbles in space. Image via NASA<\/a>\/ Goddard\/ SwRI\/ Johns Hopkins APL.<\/p>\n

Donaldjohanson is a small asteroid, about 1\/2 mile (800 m) across, in the main asteroid belt between Mars and Jupiter.
\nNASA\u2019s Lucy spacecraft confirmed it is oblong and peanut-shaped in 2025.
\nAnd it found the strange asteroid is wobbling in two directions: end-over-end and along its horizontal axis.<\/p>\n

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.<\/a><\/p>\n

Tiny asteroid wobbles in space<\/p>\n

Donaldjohanson<\/a> is an intriguing asteroid in the main asteroid belt between Mars and Jupiter. NASA\u2019s Lucy<\/a> spacecraft flew past<\/a> Donaldjohanson on April 20, 2025, and found that the 1\/2 mile (800 m) diameter asteroid is elongated and shaped like a peanut. And now, astronomers have announced another discovery spawned from the flyby. <\/p>\n

Researchers with the Southwest Research Institute (SwRI) said<\/a> on June 18, 2026, that the asteroid wobbles during its rotation. It rotates end-over-end every 10.5 Earth days, and wobbles on its horizontal axis every 26.5 days.<\/p>\n

It\u2019s an interesting surprise for astronomers, who had expected it to move through space in a steady pattern. Lead author and deputy principal investigator for the Lucy mission, Simone Marchi<\/a>, said<\/a>:<\/p>\n

This is just one of many surprising things learned since NASA\u2019s Lucy spacecraft flew by Donaldjohanson on April 20, 2025.<\/p>\n

The researchers published<\/a> their peer-reviewed<\/a> results about this tiny tumbling world in Science on June 18, 2026.<\/p>\n

New by me for @skyandtelescope.bsky.social : how slowing spin makes gravity win (over centrifugal acceleration) for the peanut asteroid 52246 Donaldjohanson, visited by the Lucy mission last April skyandtelescope.org\/uncategorize\u2026<\/p>\n

\u2014 Emily Lakdawalla ????? Uranus Expert (@elakdawalla.bsky.social)<\/a> 2026-06-18T18:26:19.291Z<\/a><\/p>\n

Donaldjohanson does not spin steadily. Lucy observations show the 0.8-kilometer asteroid turns end over end every 10.5 days and wobbles around its horizontal axis every 26.5 days. doi.org\/hb77fc<\/p>\n

\u2014 Science X \/ Phys.org (@sciencex.bsky.social)<\/a> 2026-06-18T17:20:20-04:00<\/a><\/p>\n

Shaped like a peanut<\/p>\n

Astronomers suspected that Donaldjohanson was oblong in shape based on ground-based observations from Earth. And the Lucy spacecraft confirmed that. Lucy revealed that the asteroid is actually shaped like a peanut. It has two large lobes connected by a narrow neck. It looks like what scientists call an elongated contact binary<\/a> (an object formed when two small bodies collide).<\/p>\n

Lucy images confirmed its elongated shape, initially suggested by Earth-based telescope observations. The flyby revealed that the small asteroid, half a mile in diameter, resembles a peanut, with a two-lobed structure connected by a narrower neck.<\/p>\n

\"PhotosView larger<\/a>. | Comparison of the spectra<\/a> from Donaldjohanson and the meteorite QUE 97990. Both are rich in clay minerals<\/a>, evidence of being exposed to liquid water in the past. Image via NASA\/ Goddard\/ SwRI\/ Dan Gallagher\/ SwRI<\/a>.
\nRich in clay minerals<\/p>\n

In addition, Lucy discovered clay minerals<\/a> on Donaldjohanson. Clay minerals require liquid water to form. So scientists say that the asteroid likely formed from the fragments of a larger asteroid that broke apart about 155 million years ago. That asteroid was rich in water and carbon.<\/p>\n

The composition of these minerals is similar to that of other carbonaceous asteroids<\/a>, or asteroids rich in carbon. But on Donaldjohanson, the aqueous (water) stage seems to have ended earlier. That might have been due to insufficient heat or water.<\/p>\n<\/p>\n

\"Serious-lookingSimone Marchi<\/a> at SwRI is the deputy principal investigator of the Lucy mission and lead author of the new study about Donaldjohanson. Image via Simone Marchi<\/a>.
\nJourney to Jupiter<\/p>\n

Lucy\u2019s primary mission is still ahead. It is now en route to Jupiter, where it will explore two groups of asteroids: the Greek asteroids, which lead Jupiter in its orbit, and the Trojan asteroids, which trail behind it. Together, these two groups are known as the Jupiter Trojans<\/a>. Marchi said:<\/p>\n

This encounter gave us an opportunity to test our instruments and our procedures to make sure we are ready when we get to Jupiter\u2019s Trojans. Once we start learning more about the Trojans, a completely different population of space rocks with very different histories, our understanding of solar system formation is likely to be challenged.<\/p>\n

Lucy is expected to reach the first Trojan asteroid, Eurybates<\/a>, in August 2027.<\/p>\n

The Lucy spacecraft is named for a famous fossilized skeleton<\/a> found in Africa in 1974. Likewise, Donaldjohanson is named for the paleoanthropologist best known for discovering the Lucy fossil.<\/p>\n

Bottom line: New analysis shows that peanut-shaped asteroid Donaldjohanson wobbles in space in two directions. The Lucy spacecraft now continues its journey toward Jupiter\u2019s Trojans.<\/p>\n

Source: The Lucy flyby of (52246) Donaldjohanson: A bilobed asteroid with tumbling rotation<\/a><\/p>\n

Via SwRI<\/a><\/p>\n

Read more: Lucy spacecraft 1st images of asteroid Donaldjohanson!<\/a><\/p>\n

Read more: Lucy mission to Jupiter\u2019s Trojans gets the nod from NASA<\/a><\/p>\n

Paul Scott Anderson
\n View Articles<\/a><\/p>\n

About the Author:<\/p>\n

Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
\n
\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
\n
\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n","protected":false},"excerpt":{"rendered":"This is asteroid Donaldjohanson, as seen by NASA\u2019s Lucy spacecraft during a flyby on April 20, 2025. Its…\n","protected":false},"author":2,"featured_media":760173,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[270949,49,48,270950,132657,66,306],"class_list":["post-760172","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-asteroid-wobbles-in-space","tag-ca","tag-canada","tag-donaldjohanson","tag-lucy","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/760172","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=760172"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/760172\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/760173"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=760172"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=760172"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=760172"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}