Volcanic domes beneath the clouds
Map. Magellan stereoscopic radar pair: the same terrain observed at 28.5- and 15.6-degree look angles, illuminated by radar from the left. A small dome is inferred to be about 140 metres high and 6 kilometres wide. Different radar brightness is viewing geometry, not a filmed change or sunlight; acquisition dates are not supplied here.
NASA/JPL image-use policy · credited mission imagery, resized to WebP
· Original image source · Image licenceRadar reveals rounded volcanic domes and fractured surfaces hidden beneath Venus’s permanent cloud cover.
- World
- Venus
- Case date or period
- Magellan radar observations
Look closer
Magellan’s radar observations exposed broad domes on Venus that are difficult to imagine from the planet’s featureless cloud portrait. Their margins and fractures invite close comparison.
Follow the evidence
One product is stereoscopic; the others show separate dome localities. Radar brightness depends on surface properties and geometry, so bright areas do not simply correspond to sunlight.
The ground beneath a dome affects its shape
Matthew Borrelli, Chloé Michaut and Joseph O’Rourke modelled viscous flows spreading over an elastic surface. Allowing the ground to bend made the simulated domes flatter on top and steeper at their edges. Comparison with Narina Tholus’s surrounding topography favoured a substantial load and ruled against highly bubbly, very low-density lava within that model. Andesite, rhyolite and less-vesiculated basalt remained possible. Radar shape therefore tests emplacement physics without uniquely measuring lava chemistry or proving that every Venusian dome formed the same way.
Sources & further reading
- Venus - Stereoscopic Images of Volcanic Domes — NASA Image and Video Library / JPL
- Venus - Volcanic Domes East of Beta Regio — NASA Image and Video Library / JPL
- Venus - Volcanic Domes on Flank of Volcanic Maat in East Ovda Region — NASA Image and Video Library / JPL
- Formation of Pancake Domes on Venus as Viscous Flows Over an Elastic Lithosphere — Borrelli and colleagues — Original investigators / research publisher