Scientists have identified 37 volcanic structures on Venus that appear to be recently active - and probably still are today - painting the picture of a geologically dynamic planet and not a dormant world as long thought.

The research focused on ring-like structures called coronae, caused by an upwelling of hot rock from deep within the planet's interior, and provided compelling evidence of widespread recent tectonic and magma activity on Venus's surface, researchers said on Monday.

Many scientists long had thought Venus, lacking the plate tectonics that gradually reshape Earth's surface, was essentially dormant geologically for the past half billion years.

"Our work shows that some of that interior heat is still able to reach the surface even today. Venus is clearly not so geologically dead or dormant as previously thought," said Earth and planetary scientist Anna Gülcher of the Institute of Geophysics in Zurich, lead author of the research published in the journal Nature Geoscience.

The researchers determined the type of geological features that could exist only in a recently active corona - a telltale trench surrounding the structure. Then they scoured radar images of Venus from NASA's Magellan spacecraft in the 1990s to find coronae that fit the bill. Of 133 coronae examined, 37 appear to have been active in the past two million to 3 million years, a blink of the eye in geological time.

"In my opinion, many of these structures are indeed active today," said University of Maryland geophysicist and study co-author Laurent Montesi.

Coronae are essentially fields of lava flows and major faults spanning a large circular area. Many of the 37 reside within in a gigantic ring in the planet's Southern Hemisphere, including a colossal corona called Artemis 1,300 miles (2,100 kilometers) in diameter.

Venus, Earth's closest and just slightly smaller planetary neighbor, is covered by clouds of sulfuric acid and has surface temperatures hot enough to melt lead.

(Cover: Two coronae, ring-like structures formed when hot material from deep inside the planet rises through the mantle and erupts through the crust, are observed on the surface of Venus in a 3D rendition provided to Reuters, July 20, 2020. /Reuters)