Venus is similar in size to Earth, but it stays far hotter because its thick atmosphere traps heat, as shown by NASA’s facts. That extreme heat has not erased the planet’s scars, which include hundreds of ringed features called coronae.
A new peer-reviewed study explains how a hidden layer deep inside the planet can block rising hot rock and set the stage for those rings.
The work points to a barrier about 400 miles down that shapes both small and huge volcanic landforms.
Lead author Madeleine Kerr, a Ph.D. candidate at Scripps Institution of Oceanography at UC San Diego (UCSD), led the modeling and analysis.
Her team used physics based simulations to test how Venus moves heat from its interior to its surface.
“The first full Venus model that can actually express the surface of today, that is the goal,” said Kerr.
She emphasized that Venus gives scientists a front row seat to study why two similar planets could have taken such different evolutionary paths.
What are Venus’ coronae
On Venus, coronae are round or oval volcano tectonic structures framed by concentric fractures. They can be shallow depressions or raised rims, and many show signs of past eruptions and faulting.
Scientists view coronae as surface footprints of activity in the mantle below. They sit between small volcanoes and continent scale highlands in size, and their variety hints at more than one formation path.
The new work identifies a mantle layer that acts like a barrier to vertical motion at roughly 400 miles depth.
In this mantle transition zone (MTZ), minerals change structure with pressure and temperature, which alters how buoyant hot or cold rock becomes.
That change can reverse the usual rule that hot material rises and cold material sinks.
When that happens, upwellings stall and spread sideways, and downwellings can pool until they fail and plunge, all consistent with the study linked earlier.
Two barrier paths on Venus
The models show two distinct routes for moving heat upward. Large mantle upwellings can be big enough to punch through the barrier and build swells over about 1,200 miles across.
Smaller plumes rise from the pooled warm layer beneath the barrier and build the more common coronae, often tens to hundreds of miles wide.
This split in plume sizes helps explain why Venus shows both broad rises and clusters of smaller ringed features in the same regions.
Venus has a stagnant lid, meaning its outer shell is a single rigid plate rather than a patchwork of moving plates like Earth. That lid locks in heat, so the planet bleeds energy through drips and plumes from below.
A mantle plume is a column of hot rock that rises from deep inside a planet toward the surface.
A Clapeyron slope describes how a mineral phase change shifts with temperature and pressure, and a negative slope in the transition zone can impede vertical flow.
Counting the coronae on Venus
How many coronae exist is not a trivial detail. A 2024 updated database reports more than 600 confirmed coronae, a tally far above early catalogs.
Those counts, plus their global spread, point to a planet that vents heat in many places rather than along a few steady plate boundaries. That pattern matches expectations for a hot interior under a stiff outer shell.
Venus also preserves a lava channel called Baltis Vallis that runs for about 4,300 miles, the longest known channel in the solar system.
One recent 2025 paper shows that gentle ups and downs along this channel record mantle driven surface deformation.
The same models that produce a glass ceiling layer also make surface undulations with wavelengths of a few hundred miles. That scale agrees with the deformation signals extracted from the channel’s topography.
Why Venus matters to Earth
Venus and Earth started with similar size and bulk composition. Their paths split as Venus lost surface water and locked into a stagnant lid while Earth kept mobile plates.
Understanding which mineral transitions control Venus’s mantle today helps frame how rocky planets cool and resurface. That insight matters for reading Earth’s early history and for interpreting rocky worlds around other stars.
Better gravity and radar data will narrow the range of possible mantle temperatures and viscosities. The VERITAS gravity investigation is designed to measure signals that depend on interior structure.
Those data can test whether a barrier near 400 miles depth is really reshaping mantle flow. They can also reveal how often smaller plumes rise, and how that timing lines up with corona clusters at the surface.
More Venus coronae studies ahead
The models use a dry pyrolite composition, a common choice for approximating Earth’s upper mantle, because Venus’s exact mix and water content remain unknown.
Different chemistries could shift the depth and strength of the phase changes that create the barrier.
Even so, the explanation ties together several loose ends without resorting to rare conditions. It accounts for the size gap between broad rises and smaller rings, and it matches the surface deformation signals extracted from a channel thousands of miles long.
Science advances when a simple idea survives hard tests. Kerr’s team pushed beyond earlier approximations to include mineral physics that matter at Venus temperatures.
The drive behind this research is as much about curiosity as it is about discovery. Each new model brings scientists closer to explaining how a planet so similar to Earth ended up on such a different path.
The study is published in Proceedings of the National Academy of Sciences.
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