New UC San Diego research suggests a deep barrier in Venus’s mantle explains its strange volcanic surface features.
Cracking the Mystery of Venus
For decades, scientists have puzzled over why Venus—so close in size and composition to Earth—looks so radically different.
A 2025 study led by Madeleine Kerr at UC San Diego offers a new explanation: a “glass ceiling” deep inside Venus’s mantle that blocks heat from rising normally.
This barrier could explain why the planet has its distinctive crown-shaped volcanic structures, known as coronae, and why its surface evolution differs so much from Earth’s.
The ‘Glass Ceiling’ Effect
According to the study, published in PNAS:
- About 595 km beneath the surface, a dense mantle layer traps most heat plumes.
- Only the most powerful bursts of heat manage to break through, forming large volcanic rises and coronae.
- The process is triggered when dense rock sinks, reshaping mantle flow and creating localized surface features instead of widespread volcanic activity.
This mechanism helps explain why Venus lacks plate tectonics like Earth but still shows dramatic volcanic formations.
Hotter Than Earth’s Mantle
The researchers used advanced computer simulations to model these processes.
Their findings suggest that this “mantle ceiling” only works if Venus’s mantle is between 250 and 400 K (Kelvins) hotter than Earth’s.
That extra heat makes the mantle more buoyant, but the ceiling layer prevents it from venting evenly—leading to Venus’s patchy, intense volcanism.
Why It Matters
Understanding Venus’s internal structure is critical because:
- It reveals how similar planets can evolve differently, even with near-identical size and composition.
- It offers insights into mantle convection, a key process for shaping planetary surfaces.
- It helps scientists prepare for data from future Venus missions like NASA’s VERITAS and ESA’s EnVision, which will map the planet in detail.
