“But given it likely never had oceans, it is hard to imagine Venus ever having supported Earth-like life, which requires liquid water.”
The second theory is that Venus was born hot, and liquid water has never been able to condense at the surface.
But, based on the composition of the volcanic gases necessary to sustain the Venusian atmosphere, the researchers found that volcanic gases on Venus are at most six percent water.
These dry eruptions suggest that Venus’s interior, the source of the magma that releases volcanic gases, is also dehydrated.
But if Venus was never habitable, then it makes Venus-like planets elsewhere less likely candidates for habitable conditions or life.
Despite decades of conjecture that Venus, our nearest planetary neighbor, was once far more like Earth than it is now, a team of astronomers has discovered that Venus has never been habitable.
Researchers from the University of Cambridge examined the chemical makeup of the Venusian atmosphere and concluded that there was never enough water for oceans to form at the surface because the planet’s interior is now too dry. Rather, the planet has probably been a hostile, blazing world for all of its history.
Findings published in the journal Nature Astronomy have implications for both the hunt for extrasolar life and our understanding of Earth’s uniqueness. According to the study, astronomers should concentrate on exoplanets that resemble Earth more than Venus, even though many of them are similar to the planet.
From a distance, Venus and Earth appear to be siblings because they are both rocky and nearly the same size. On closer inspection, however, Venus resembles an evil twin more because its surface has a mean temperature of nearly 500°C and is covered in dense clouds of sulfuric acid.
Notwithstanding these harsh circumstances, astronomers have been studying whether Venus formerly had liquid oceans that could sustain life or if there is currently some enigmatic type of “aerial” life present in its dense clouds.
“Until we send probes at the end of this decade, we won’t know for sure whether Venus can or did support life,” stated Tereza Constantinou, a Ph.D., the first author. A. pupil at the Institute of Astronomy in Cambridge. However, it is difficult to imagine Venus ever having supported life akin to Earth, which needs liquid water, given that it most likely never had oceans. “.
Astronomers concentrate on planets orbiting their host stars in the habitable zone, where temperatures are high enough for liquid water to exist on the planet’s surface, when looking for life elsewhere in our galaxy. The location of this habitable zone around a star is strongly limited by Venus.
“Venus, despite being the nearest planet to us, is significant for exoplanet research because it provides us with a rare chance to investigate a planet that evolved very differently from ours, located at the edge of the habitable zone,” Constantinou said.
There are two main hypotheses regarding the possible evolution of Venus’s conditions since its formation 4–6 billion years ago. First, Venus was once a temperate planet with liquid water on its surface, but a runaway greenhouse effect brought on by extensive volcanic activity made the planet increasingly hotter.
According to the second theory, liquid water has never been able to condense at the surface of Venus because it was born hot.
According to Constantinou, “both of those theories are based on climate models, but we wanted to take a different approach based on observations of Venus’ current atmospheric chemistry.”.
Given that the planet’s interior and exterior are constantly in chemical communication with one another, any chemicals that are taken out of the atmosphere should also be added back to maintain the stability of the Venusian atmosphere. “..”.
The scientists estimated how quickly water, carbon dioxide, and carbonyl sulfide molecules are currently being destroyed in Venus’ atmosphere and how volcanic gases must replenish them to maintain the atmosphere’s stability.
Volcanism gives a glimpse into the interior of rocky planets like Venus by supplying gases to the atmosphere. As magma rises to the surface from the mantle, gases from the planet’s deeper regions are released.
Since our planet’s interior is rich in water, most volcanic eruptions on Earth produce steam. However, the researchers discovered that the volcanic gases on Venus contain no more than 6% water by composition, which is necessary to maintain the Venusian atmosphere. These dry eruptions imply that the magma that releases volcanic gases from Venus’s interior is likewise dehydrated.
With a series of flybys and a probe sent to the surface, NASA’s DAVINCI mission will be able to test and confirm whether Venus has always been a dry, inhospitable planet by the end of this decade. The findings might aid astronomers in focusing their search for planets that could sustain life in orbit around other galaxies.
Constantinou stated, “If Venus was habitable in the past, it would mean other planets we have already found might also be habitable.”. The atmospheres of planets near their host star, such as Venus, are best studied by instruments like the James Webb Space Telescope. However, if Venus was never habitable, then planets that resemble it elsewhere are less likely to support life or have habitable conditions.
“It’s kind of sad to learn that Venus wasn’t a planet much closer to our own, especially since we would have loved to discover that it was. However, in the end, it’s more beneficial to concentrate the search on planets that are most likely to be able to support life—at least life as we know it. “.
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