NASA Study: Massive Volcanism May Have Changed Ancient Venus' Climate

NASA Study: Massive Volcanism May Have Changed Ancient Venus’ Climate

Hundreds to thousands of centuries of volcanic activity and the eruption of massive amounts of material may have helped transform Venus from a temperate and humid world into the acidic hothouse it is today, a NASA paper suggests.

The paper also discusses those “great magmatic provinces” in Earth’s history that caused multiple mass extinctions on our own planet millions of years ago.

“By understanding the records of large magmatic provinces on Earth and Venus, we can determine whether these events may have caused Venus’ current state,” said Dr. Michael J. Way of NASA’s Goddard Institute for Space Studies in New York. Way is the lead author of the paper, which was published April 22 in the Planetary Science Journal.

Large igneous provinces are the result of periods of large-scale volcanism lasting tens or even hundreds of thousands of years. They can deposit more than 100,000 cubic miles of volcanic rock on the surface. At the high end, this could be enough molten rock to bury the entire state of Texas half a mile deep.

Venus today has surface temperatures averaging about 864 F and an atmosphere 90 times that of Earth’s surface pressure. According to the study, these massive volcanic eruptions could have triggered these conditions at some point in Venus’ ancient history. In particular, the occurrence of multiple such eruptions in a short geological time span (within a million years) could have resulted in an uncontrollable greenhouse effect, triggering the planet’s transition from wet and temperate to hot and dry.

Large fields of solidified volcanic rocks collectively cover 80% of Venus’ surface, Way said. “Although we are not yet sure how often the events that created these fields occurred, we should be able to narrow them down by studying Earth’s own history.”

Life on Earth has experienced at least five major extinction events since the origin of multicellular life some 540 million years ago, each wiping out more than 50% of animal life on the planet. According to this study and others before it, the majority of these extinction events were caused or exacerbated by the type of eruptions that produce large eruptive provinces. In Earth’s case, the climate disturbances from these events were not sufficient to cause a runaway greenhouse effect like that on Venus, for reasons Way and other scientists are still working to determine.

NASA’s next missions to Venus, scheduled for launch in the late 2020s — the Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) Mission and the Venus Emissivity, Radio Science, InSAR, Topography, And Spectroscopy (VERITAS ) Mission – The aim is to investigate the origin, history and current state of Venus in unprecedented detail.

“A key goal of DAVINCI is to narrow down the history of the water on Venus and when it may have disappeared in order to gain more insight into how Venusian climate is changing over time,” Way said.

The DAVINCI mission will precede VERITAS, an orbiter designed to survey the surface and interior of Venus from high above, to better understand its volcanic and volatile history, and thus Venus’ journey to its current state. The data from both missions could help scientists narrow the exact record of how Venus may have transitioned from wet and temperate to dry and muggy. It can also help us better understand how volcanism has affected life here on Earth in the past and how it may continue to do so in the future.

This study was supported by Goddard Space Flight Center’s Sellers Exoplanet Environments Collaboration (SEEC) and was part of NASA’s Nexus for Exoplanet System Science (NExSS) RCN.

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