Regolith

[[File:Erosregolith.jpg|thumb|Taken from just 250 m above the surface of Eros as the ''[[NEAR Shoemaker]]'' spacecraft was landing, this image shows an area that is only 12 m across.]]

[[File:Erosregolith.jpg|thumb|Taken from just 250 m above the surface of Eros as the ''[[NEAR Shoemaker]]'' spacecraft was landing, this image shows an area that is only 12 m across.]]

Asteroids commonly have [[Regolith-hosted rare earth element deposits|regoliths]] produced by impact and other surface-altering processes.{{Cite journal |last=Housen |first=Kevin R. |last2=Wilkening |first2=Laurel L. |last3=Chapman |first3=Clark R. |last4=Greenberg |first4=Richard |date=1979-09-01 |title=Asteroidal regoliths |url=https://www.sciencedirect.com/science/article/pii/0019103579901453 |journal=Icarus |volume=39 |issue=3 |pages=317–351 |doi=10.1016/0019-1035(79)90145-3 |issn=0019-1035}}{{Citation |last=Rivkin |first=Andrew |title=An Overview of the Asteroids and Meteorites |date=2013 |work=Planets, Stars and Stellar Systems |pages=376–429 |url=https://link.springer.com/rwe/10.1007/978-94-007-5606-9_8 |access-date=2026-04-20 |publisher=Springer, Dordrecht |language=en |doi=10.1007/978-94-007-5606-9_8 |isbn=978-94-007-5606-9}} [[Spacecraft]] observations have shown that [[Asteroid|asteroids]]' regolith can range from fine-grained deposits to coarse, boulder-rich [[debris]]{{Cite journal |last=Denevi |first=Brett W. |last2=Beck |first2=Andrew W. |last3=Coman |first3=Ecaterina I. |last4=Thomson |first4=Bradley J. |last5=Ammannito |first5=Eleonora |last6=Blewett |first6=David T. |last7=Sunshine |first7=Jessica M. |last8=De Sanctis |first8=Maria Cristina |last9=Li |first9=Jian‐Yang |last10=Marchi |first10=Simone |last11=Mittlefehldt |first11=David W. |last12=Petro |first12=Noah E. |last13=Raymond |first13=Carol A. |last14=Russell |first14=Christopher T. |date=2016-12 |title=Global variations in regolith properties on asteroid Vesta from Dawn's low‐altitude mapping orbit |url=https://onlinelibrary.wiley.com/doi/10.1111/maps.12729 |journal=Meteoritics & Planetary Science |language=en |volume=51 |issue=12 |pages=2366–2386 |doi=10.1111/maps.12729 |issn=1086-9379}}. On [[433 Eros|Eros]], the [[NEAR Shoemaker]] mission found that the surface is dominated by a blanket of regolith, with boulders scattered across the landscape and flat, infilled low areas{{Cite journal |last=Veverka |first=J. |last2=Thomas |first2=P. C. |last3=Robinson |first3=M. |last4=Murchie |first4=S. |last5=Chapman |first5=C. |last6=Bell |first6=M. |last7=Harch |first7=A. |last8=Merline |first8=W. J. |last9=Bell |first9=J. F. |last10=Bussey |first10=B. |last11=Carcich |first11=B. |last12=Cheng |first12=A. |last13=Clark |first13=B. |last14=Domingue |first14=D. |last15=Dunham |first15=D. |date=2001-04-20 |title=Imaging of Small-Scale Features on 433 Eros from NEAR: Evidence for a Complex Regolith |url=https://www.science.org/doi/10.1126/science.1058651 |journal=Science |volume=292 |issue=5516 |pages=484–488 |doi=10.1126/science.1058651}}. Samples returned from Itokawa by the [[Hayabusa (spacecraft)|Hayabusa]] mission provided the first direct asteroid regolith grains for laboratory study and revealed evidence of processes such as [[space weathering]] and solar-wind implantation{{Cite journal |last=Matsumoto |first=Toru |last2=Tsuchiyama |first2=Akira |last3=Miyake |first3=Akira |last4=Noguchi |first4=Takaaki |last5=Nakamura |first5=Michihiko |last6=Uesugi |first6=Kentaro |last7=Takeuchi |first7=Akihisa |last8=Suzuki |first8=Yoshio |last9=Nakano |first9=Tsukasa |date=2015-09-01 |title=Surface and internal structures of a space-weathered rim of an Itokawa regolith particle |url=https://www.sciencedirect.com/science/article/pii/S0019103515002031 |journal=Icarus |volume=257 |pages=230–238 |doi=10.1016/j.icarus.2015.05.001 |issn=0019-1035}}{{Cite journal |last=Keller |first=Lindsay P. |last2=Berger |first2=Eve L. |date=2014-07-15 |title=A transmission electron microscope study of Itokawa regolith grains |url=https://doi.org/10.1186/1880-5981-66-71 |journal=Earth, Planets and Space |language=en |volume=66 |issue=1 |pages=71 |doi=10.1186/1880-5981-66-71 |issn=1880-5981}}.

Asteroids have regoliths developed by meteoroid impact. The final images taken by the [[NEAR Shoemaker]] spacecraft of the surface of [[433 Eros|Eros]] are the best images of the regolith of an asteroid.{{cn|date=March 2025|reason=The images taken of Bennu's regolith by OSIRIS-REx were from much closer distance (compare the article about that asteroid), so this may be outdated.}} The Japanese [[Hayabusa (spacecraft)|Hayabusa]] mission also returned clear images of regolith on an asteroid so small it was thought that gravity was too low to develop and maintain a regolith. The asteroid [[21 Lutetia]] has a layer of regolith near its north pole, which flows in landslides associated with variations in albedo.{{cite journal

Subsequent missions greatly expanded understanding of asteroid regolith. [[Hayabusa2|Hayabusa 2]] returned samples from [[162173 Ryugu|Ryugu]] in 2020, and early analysis showed that the material is primitive and rich in water and organic matter{{Cite journal |last=Yada |first=Toru |last2=Abe |first2=Masanao |last3=Okada |first3=Tatsuaki |last4=Nakato |first4=Aiko |last5=Yogata |first5=Kasumi |last6=Miyazaki |first6=Akiko |last7=Hatakeda |first7=Kentaro |last8=Kumagai |first8=Kazuya |last9=Nishimura |first9=Masahiro |last10=Hitomi |first10=Yuya |last11=Soejima |first11=Hiromichi |last12=Yoshitake |first12=Miwa |last13=Iwamae |first13=Ayako |last14=Furuya |first14=Shizuho |last15=Uesugi |first15=Masayuki |date=2022-02 |title=Preliminary analysis of the Hayabusa2 samples returned from C-type asteroid Ryugu |url=https://www.nature.com/articles/s41550-021-01550-6 |journal=Nature Astronomy |language=en |volume=6 |issue=2 |pages=214–220 |doi=10.1038/s41550-021-01550-6 |issn=2397-3366}}. [[NASA]]'s [[OSIRIS-REx]] mission returned rocks and dust from [[101955 Bennu|Bennu]] to Earth in 2023; initial studies found carbon-rich material and evidence of water, while spacecraft observations showed that Bennu's surface is unexpectedly rugged and dominated by boulders rather than broad, smooth deposits{{Cite journal |last=Lauretta |first=Dante S. |last2=Connolly |first2=Harold C. |last3=Aebersold |first3=Joseph E. |last4=Alexander |first4=Conel M. O'D. |last5=Ballouz |first5=Ronald‐L. |last6=Barnes |first6=Jessica J. |last7=Bates |first7=Helena C. |last8=Bennett |first8=Carina A. |last9=Blanche |first9=Laurinne |last10=Blumenfeld |first10=Erika H. |last11=Clemett |first11=Simon J. |last12=Cody |first12=George D. |last13=DellaGiustina |first13=Daniella N. |last14=Dworkin |first14=Jason P. |last15=Eckley |first15=Scott A. |date=2024-09 |title=Asteroid (101955) Bennu in the laboratory: Properties of the sample collected by OSIRIS ‐ REx |url=https://onlinelibrary.wiley.com/doi/10.1111/maps.14227 |journal=Meteoritics & Planetary Science |language=en |volume=59 |issue=9 |pages=2453–2486 |doi=10.1111/maps.14227 |issn=1086-9379}}. [[Rosetta (spacecraft)|Rosetta]] observation of [[21 Lutetia]] identified smooth regolith deposits, large boulders, and landslides, while close-up images of the [[Double Asteroid Redirection Test|Double Asteroid Redirection Test (DART)]] impact on [[Dimorphos]] and the resulting dusty ejecta helped clarify how loose surface materia behave on small bodies in microgravity {{cite journal

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==Titan==

==Titan==