Venus and Earth may have formerly existed as twin utopias, featuring temperate climates and extensive oceans. However, at some point, Venus experienced a disastrous shift.
In a recent investigation, planetary scientists examined how Venus changed from an Earth-like refuge into the blazing, unwelcoming planet we observe today. Utilizing sophisticated simulations, the researchers modeled the geological evolution of the planet, uncovering how volcanic activity and internal dynamics likely fueled this striking transformation. These results, released in the journal *Science Advances*, imply that Venus underwent a series of enormous volcanic eruptions and geological disturbances, ultimately altering its surface and atmosphere into the extreme environment known today.
“Venus is a thoroughly uninviting place,” stated Matthew Weller, a planetary geophysicist at Rensselaer Polytechnic Institute and coauthor of the research. “It’s sufficiently hot to melt lead.”
### A Tale of Two Planets
Notwithstanding their considerable differences now, Venus and Earth possess many commonalities. They are nearly identical in size, made up of comparable rocky substances, and orbit within the inner solar system. Yet, while Earth remains mild and bustling with life, Venus has transformed into a nightmarish terrain with surface temperatures comparable to a pizza oven, an atmospheric pressure 92 times greater than that of Earth, and a history steeped in widespread volcanic activity.
“You have these two planets positioned there, and then one veers off in a different direction,” Weller elucidated.
To comprehend how Venus diverged so significantly, researchers relied on 3D computer models that simulated the inner workings of the planet. These models illustrated how the convecting mantle—the layer of hot, flowing rock beneath the surface—fractured Venus’ crust, instigating volcanic eruptions that released vast quantities of gas into the atmosphere. Over time, these eruptions established a runaway greenhouse effect, scorching the planet and condemning it to its current state. “Venus essentially cooked itself,” Weller remarked.
### The Volcanic Domino Effect
The simulations indicated that Venus likely underwent a sequence of “stairstep” events, where internal geological activity repeatedly fractured the crust. Each incident released substantial volcanic outgassing, contributing enough gases to thicken the atmosphere by three to ten times Earth’s atmospheric pressure. Over millions of years, these occurrences compounded, resulting in the staggering surface pressure of 1,350 psi—comparable to the weight of a small car pressing on a single square inch.
The exact timeline of these catastrophic events remains unclear. They could have transpired billions of years ago or as “recently” as hundreds of millions of years ago. For a significant portion of its history, Venus may have closely resembled Earth, featuring oceans, coastlines, and a temperate climate. The two planets, just 67 million miles apart, could have both been suitable for life.
“It’s conceivable both were habitable,” Weller acknowledged.
### A Planetary Warning
The pronounced divergence between Earth and Venus highlights how radically planets can evolve over extended periods. This has important implications for exoplanet research—remote worlds orbiting different stars. A planet that seems Earth-like today might appear entirely dissimilar in the future. Similarly, Earth itself might experience profound changes given the right (or wrong) circumstances. “It demonstrates how easily an Earth-like planet can become like Venus,” Weller stressed.
The “million-dollar question,” however, revolves around what initially directed Venus onto this destructive trajectory. One possibility is that a colossal volcanic event occurred at a pivotal moment, initiating a feedback loop of uncontrollable volcanism and atmospheric alterations. On Earth, processes like rock weathering assist in regulating the climate by extracting carbon dioxide from the atmosphere over millions of years. But on Venus, the extreme heat likely halted plate tectonics, a crucial mechanism for planetary stabilization. Lacking this balancing influence, Venus spiraled into its present condition and could not recover.
### Unlocking Venus’ Secrets
In the near future, humanity may attain a clearer insight into Venus’ enigmatic history. NASA’s anticipated DAVINCI mission (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) is set to illuminate the planet’s past. The mission will deploy a titanium probe to plunge through Venus’ thick atmosphere, gathering data and capturing images of its surface. Over the course of an hour, the probe will analyze gases, perform experiments, and provide unprecedented revelations regarding Venus’ geology and climate.
This mission could help address lingering inquiries about why Venus and Earth, once so alike, have wound up on such vastly different paths. As scientists delve deeper into the study of Venus, they may unveil lessons not only about our planetary neighbor but also about the fragile balance that supports life on Earth.