Venus often referred to as Earth’s twin due to its similar size and rocky composition has been at the center of one of astronomy’s most enduring mysteries: Did it ever host oceans? A new study has finally provided an answer, and it’s not what some scientists had hoped.
According to research published in the journal Nature Astronomy, Venus has likely been a dry, desolate world throughout its history. By analyzing the chemical composition of Venus’s atmosphere, scientists concluded that the planet’s interior has a remarkably low water content. This finding contradicts earlier hypotheses suggesting Venus might once have harbored oceans or even supported conditions favorable for life.
The key lies in volcanic activity. On Earth, volcanic eruptions release large amounts of water vapor, which reflects the planet’s water-rich interior. However, volcanic gases on Venus contain less than 6% water vapor, a stark contrast that points to a dry mantle. Tereza Constantinou, a researcher at the University of Cambridge and lead author of the study, said the results provide strong evidence against Venus ever being habitable.
“The atmospheric chemistry suggests that volcanic eruptions on Venus release very little water, implying that the planet’s interior is equally dry,” Constantinou explained. “This is consistent with Venus having had a long-lasting dry surface and never having been a hospitable environment.”
Twin Planets with Divergent Fates
Venus and Earth share many similarities. Both are rocky planets of comparable size and are relatively close to the Sun. Yet, their evolutionary paths could not be more different.
While Earth is an ocean-covered world teeming with life, Venus is a scorched wasteland with surface temperatures around 465°C (869°F). Its atmospheric pressure is 90 times greater than Earth’s, and its skies are filled with clouds of sulfuric acid.
This divergence raises profound questions about planetary evolution. Scientists have long debated whether Venus once had a temperate climate with liquid water on its surface or whether it has always been as inhospitable as it is today. The new findings lean strongly toward the latter theory, suggesting that Venus was never able to cool sufficiently to allow water to condense into oceans.
Comparisons with Mars
While Venus appears to have always been dry, Mars tells a different story. Geological evidence indicates that the Red Planet had vast oceans billions of years ago. Recent research even suggests that liquid water might still exist deep beneath its surface, trapped within fractured rocks.
Venus, by contrast, shows no signs of such features. Its parched surface and hostile atmosphere underscore the unique challenges of understanding a planet that is, in many ways, Earth’s closest counterpart.
Looking to the Future
Despite its harsh conditions, Venus is set to become the focus of renewed exploration in the coming decade. NASA’s DAVINCI mission, slated for the 2030s, aims to study Venus’s atmosphere and surface in detail, employing both flybys and a descent probe. The European Space Agency’s EnVision mission, also planned for the 2030s, will map Venus using radar and conduct atmospheric studies.
“Venus provides a natural laboratory for studying how habitability or the lack of it evolves,” Constantinou said.
As these missions prepare to unlock new secrets about Venus, the planet’s past remains a cautionary tale of how even a world with Earth-like qualities can evolve into an uninhabitable inferno.