Massive global volcanism covering 80% of Venus’ surface in lava may have been the decisive factor in transforming Venus from a wet and mild world into the suffocating, sulphurous, hellish planet it is today.
The surface temperature Venus is a sweltering 867 degrees Fahrenheit (464 degrees Celsius), hot enough to melt lead, and there’s a crushing pressure of 90 atmospheres beneath the dense clouds of carbon dioxide laced with corrosive sulfuric acid. Often frowned upon Soil‘Evil twin’ is Venus the victim of a runaway greenhouse effectno doubt amplified by Venus moving about 25 million miles (40 million kilometers) closer to the sa than the Earth and therefore receives more heat.
Yet there is growing evidence that Venus was not always like this, and could once have been a temperate world somewhat like Earth – perhaps more recent, in geological terms, than expected.
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Michael Way, of NASA’s Goddard Space Flight Center in Maryland, led much of the research that developed this new view of Venus. In their latest paper, he and his team argue that Venus’ volcanism could have ultimately been the cause of pushing the planet over the edge by sending massive amounts of carbon dioxide — as we know, a potent greenhouse gas — to Earth. The atmosphere of Venus.
In the 1990s, NASA’s radar-powered Magellan spacecraft mapped the surface of Venus, which is otherwise obscured by the planet’s dense atmosphere, and found that much of the surface was covered in volcanic basaltic rock. Such “great igneous provinces” are the result of tens of thousands, if not hundreds of thousands, of years of massive volcanism that happened at some point in the last billion years.
In particular, several of these events that may have occurred over the span of a million years, each covering hundreds of thousands of square miles or kilometers of lava, could have supplied the atmosphere of Venus with so much carbon dioxide that the climate would not have been able to handle. All the oceans would have boiled away, adding moisture to the atmosphere, and because water vapor is also a greenhouse gas, accelerating the runaway greenhouse effect. Over time, the water would have been lost to space, but the carbon dioxide and the inhospitable world remained.
“While we’re not yet sure how often the events that created these fields have occurred, we should be able to narrow it down by studying Earth’s own history,” Way said in a statement. pronunciation.
The frequency with which massive volcanic events forming large igneous provinces have occurred on Earth implies that several such events are likely to have occurred on Venus within a million years. These incidents could have damaged Venus forever.
Earth itself has had some close calls. So-called “supervolcanoes” have been linked to numerous mass extinction events on Earth over the past half billion years. For example, the Late Devonian mass extinction event 370 million years ago has been attributed by some to supervolcanism in what is now Russia and Siberia, as well as a separate supervolcano eruption in Australia. The Triassic-Jurassic mass extinction is generally credited to the formation of the largest of Earth’s great igneous provinces, the Central Atlantic Magmatic Province, 200 million years ago. Even the death of the dinosaurs 65 million years ago may have been caused by the double blow of an asteroid impact and supervolcanism in the Deccan Traps, a major igneous province in India.
For reasons unknown, similar volcanic events on Venus were much more widespread and caused a runaway greenhouse effect that transformed the planet. Meanwhile on Earth, the carbon-silicate cycle that acts as the planet’s natural thermostat, exchanging carbon dioxide and other greenhouse gases between the mantle and atmosphere over millions of years, could prevent Earth from following the same path as Venus.
Two future NASA missions will attempt to answer some of these questions. DAVINCIthe Deep Atmosphere Venus Investigation of Noble Gases, Chemistry and Imaging mission will launch later this decade, followed by VERITAS, the Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy mission in the early 2030s. The European Space Agency EnVision mission also aims to launch sometime in the 2030s, while China has proposed a possible mission called VOICEthe Venus Volcano Imaging and Climate Explorer, which if launched would reach Venus in 2027 to study the planet’s atmosphere and geology.
“A primary goal of DAVINCI is to refine the history of water on Venus and when it may have disappeared, to provide further insight into how Venus’s climate has changed over time,” Way said.
The findings have been published in the Journal of planetary science earlier this year.
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