WASHINGTON – The Earth is essentially an ocean planet, with approximately 71% of its surface submerged under water. Our nearest celestial companion, Venus, which shares similarities in size and rocky structure with our own planet, is occasionally referred to as Earth’s sister. Despite its current scorched and desolate landscape, could Venus have originally possessed vast bodies of water like those on Earth?

According to recent studies examining the water content within the planet’s depths—a crucial factor in determining if Venus ever possessed vast ocean-like bodies—the findings suggest otherwise. These scientists determined that the core of Venus appears notably devoid of moisture, aligning with theories suggesting that the celestial body became extremely arid following an initial period where its exterior resembled rivers of lava—magma—and since then has maintained a bone-dry landscape.

Water is deemed essential for life, thus the research indicates that Venus has never been inhabitable. These new insights do not back up earlier suggestions that Venus might contain underground water reserves from a vanished sea.

Volcanic activity, through the release of gases into a planet’s atmosphere, offers insights into the composition of terrestrial planets. When molten rock moves upward from the middle layer known as the mantle towards the crust, it brings with it gases originating from within the deeper sections of the interior.

On Earth, volcanic gases consist of over 60% water vapor, suggesting a water-abundant mantle. In contrast, the study found that gases from Venusian volcanoes contain at most 6% water vapor, indicating a much drier subsurface environment.

“We propose that a livable history for Venus would involve its current interior being rich in water, whereas a parched past would correlate with a presently dry interior,” stated Tereza Constantinou, a PhD student at the University of Cambridge’s Institute of Astronomy and principal author of the research paper released on Monday in the journal Nature Astronomy.

“Atmospheric chemistry indicates that volcanic eruptions on Venus emit minimal amounts of water, suggesting that the planet’s interior – which drives volcanism – is also largely devoid of moisture. This aligns with the idea that Venus has maintained a consistently arid surface and was never hospitable for life,” Constantinou noted.

Venus is the planet that orbits as the second closest to the Sun, with Earth being the third.

“There are two contrasting theories about water on Venus: one suggests it had a mild climate for eons, allowing surface liquids to persist, while the other proposes that an initially scorching-hot Venus was too warm to form any surface liquid water,” according to Constantinou.

The diameter of Venus, approximately 7,500 miles (12,000 kilometers), is slightly less than Earth’s 7,900 miles (12,750 kilometers).

“Venus and Earth are frequently referred to as sister planets due to their comparable mass, size, density, and proximity to the Sun. Nonetheless, they took very different evolutionary directions,” stated Constantinou.

“Currently, Venus boasts surface conditions that are vastly different from those on Earth, featuring an atmospheric pressure 90 times higher, surface temperatures reaching approximately 465°C (869°F), and a hazardous atmosphere filled with sulfuric acid clouds. This significant divergence highlights the distinct difficulties involved in comprehending Venus beyond merely considering it Earth’s twin,” stated Constantinou.

It seems the narrative was distinct on Mars, which is the fourth planet from the sun.

Features on Mars suggest it once had an ocean filled with liquid water billions of years ago. In contrast, similar characteristics haven’t been observed on Venus. Research released in August, derived from seismic information gathered by NASA’s automated InSight rover, indicates that Mars might contain a significant underground body of liquid water trapped beneath its crust among cracked volcanic rocks, which could potentially blanket the whole planet like one enormous sea.

Although Venus hasn’t received as much attention as Mars, upcoming missions aim to change this. In the 2030s, NASA’s anticipated DAVINCI mission will investigate Venus by analyzing data collected through flybys and a descending probe, covering everything from its atmosphere to its terrain. Similarly, during the same decade, the European Space Agency plans to launch the EnVision orbiter which will focus on conducting detailed radar imaging and studying Venus’ atmosphere.

“Venus serves as a natural laboratory for examining how conditions suitable for life—or the absence thereof—develop,” Constantinou stated.

— Reuters

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Was there ever water on Venus? Scientists now know.
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