Editing Asteroid (section)

=== Surface features ===
[[File:Vesta Cratered terrain with hills and ridges.jpg|thumb|Cratered terrain on 4 Vesta]]

Except for the "[[List of exceptional asteroids#Largest by mass|big four]]" (Ceres, Pallas, Vesta, and Hygiea), asteroids are likely to be broadly similar in appearance, if irregular in shape. {{convert|50|km|mi|abbr=on}} [[253 Mathilde]] is a rubble pile saturated with craters with diameters the size of the asteroid's radius. Earth-based observations of {{convert|300|km|mi|abbr=on}} [[511 Davida]], one of the largest asteroids after the big four, reveal a similarly angular profile, suggesting it is also saturated with radius-size craters.<ref name="Icarus-2007-v191-p616" /> Medium-sized asteroids such as Mathilde and [[243 Ida]], that have been observed up close, also reveal a deep [[regolith]] covering the surface. Of the big four, Pallas and Hygiea are practically unknown. Vesta has compression fractures encircling a radius-size crater at its south pole but is otherwise a [[spheroid]].

''[[Dawn (spacecraft)|Dawn spacecraft]]'' revealed that Ceres has a heavily cratered surface, but with fewer large craters than expected.<ref name="marchi">{{cite journal |last1=Marchi |first1=S. |last2=Ermakov |first2=A. I. |last3=Raymond |first3=C. A. |last4=Fu |first4=R. R. |last5=O'Brien |first5=D. P. |last6=Bland |first6=M. T. |last7=Ammannito |first7=E. |last8=De Sanctis |first8=M. C. |last9=Bowling |first9=T. |last10=Schenk |first10=P. |last11=Scully |first11=J. E. C. |date=26 July 2016 |title=The missing large impact craters on Ceres |journal=[[Nature Communications]] |volume=7 |pages=12257 |bibcode=2016NatCo...712257M |doi=10.1038/ncomms12257 |pmc=4963536 |pmid=27459197 |last12=Buczkowski |first12=D. L. |last13=Williams |first13=D. A. |last14=Hiesinger |first14=H. |last15=Russell |first15=C. T.}}</ref> Models based on the formation of the current asteroid belt had suggested Ceres should possess 10 to 15 craters larger than {{convert|400|km|mi|abbr=on}} in diameter.<ref name="marchi" /> The largest confirmed crater on Ceres, [[Kerwan (crater)|Kerwan Basin]], is {{convert|284|km|mi|abbr=on}} across.<ref>{{cite journal |last=David A. Williams |first= T. Kneiss |date=December 2018 |title=The geology of the Kerwan quadrangle of dwarf planet Ceres: Investigating Ceres' oldest, largest impact basin |url=https://www.sciencedirect.com/science/article/abs/pii/S0019103516305632 |url-status=live |journal=Icarus |volume=316 |pages=99–113 |bibcode=2018Icar..316...99W |doi=10.1016/j.icarus.2017.08.015 |archive-url=https://web.archive.org/web/20210816123323/https://www.sciencedirect.com/science/article/abs/pii/S0019103516305632?via%3Dihub |archive-date=16 August 2021 |access-date=16 August 2021 |s2cid=85539501}}</ref> The most likely reason for this is [[Viscoelasticity|viscous relaxation]] of the crust slowly flattening out larger impacts.<ref name="marchi" />