Vesta’s grooves and giant troughs
Event image. Dawn photographed these crossing grooves and crater chains on 22 October 2011 through its clear filter, from 666 kilometres; native sampling is about 62 metres per pixel. The markings are under a kilometre wide and lie over a crater’s smoother ejecta. Scouring and secondary impacts are proposed explanations for these small features, distinct from the giant tectonic troughs. A still photograph does not show the impacts or establish one continuous fracture.
NASA/JPL image-use policy · credited mission imagery, resized to WebP
· Original image source · Image licenceLong marks cross an asteroid that has endured enormous impacts.
- World
- Asteroids
- Case date or period
- Dawn camera observations · 2011–2012
Look closer
Dawn’s Vesta images reveal grooves, crater chains and broad troughs at different scales. Their relationships with surrounding craters offer clues to sequence and structure.
Follow the evidence
These are separate areas on Vesta. Following a pattern across images is a comparison of terrain types, not proof that every visible groove belongs to one continuous fracture.
Cracking and sliding leave different signatures
Hiu Ching Jupiter Cheng and Christian Klimczak measured six major troughs and tested Vesta’s rock strength. Troughs widest near their centres, with opposing scarp-height maxima at different positions, better fit opening cracks than simple down-dropped fault blocks. Low gravity also favours cracking over shallow sliding in their calculations. This revises the proposed fracture mechanism, not the fact that the troughs are tectonic. Their timing relative to giant impacts remains uncertain, and the result should not be applied automatically to every small groove or crater chain.
Compare a photographed trough with the rendered overview
Open the dark-and-bright trough photograph beside the huge-trough overview. The first records an actual camera viewpoint; the second reconstructs an oblique view from many photographs. Use the overview to orient the terrain, then examine edges and brightness in the direct observation. The smaller crossing chains and curved grooves come from separate areas. Similar-looking lines do not demonstrate a common mechanism, and neither view films an impact or a crack opening.
Sources & further reading
- Grooves and Crater Chains on Vesta — NASA Image and Video Library / JPL
- Huge Troughs on Vesta — NASA Image and Video Library / JPL
- Linear and Curvilinear Grooves — NASA Image and Video Library / JPL
- Large-Scale Troughs on Asteroid 4 Vesta Accommodate Opening-Mode Displacement — Cheng and Klimczak — Original investigator research paper
- Trough in Dark and Bright on Vesta — NASA Photojournal / credited mission imaging team