An artist’s rendering on the surface of Venus. Image by shutterstock Conversation.
By Richard Ernst, Carleton University
We can learn a lot about the weather reversal from our sister planet Venus. Venus currently has a temperature of 840 degrees F (450 degrees C) – the temperature of an oven self-cleaning cycle – and an atmosphere of carbon dioxide (96%) 90 times denser than Earth.
Venus is a very strange place, quite desolate, except for the clouds, about 40 miles (60 km) away where the latest discovery of phosphine may indicate floating microbial life. But the surface is quite reprehensible.
However, Venus once had an Earth-like atmosphere. According to the latest weather modeling, Venus had the same temperature as today’s Earth for most of its history. It had oceans, rain, possibly snow ice, continents and plate tectonics and more speculatively, perhaps even surface life.
Less than a billion years ago, the atmosphere changed dramatically due to the fugitive greenhouse effect. It can be speculated that the intensive period of the volcano emitted enough carbon dioxide into the atmosphere to cause the oceans to evaporate and the end of the water cycle caused this great climate change to occur.
Evidence of change
This hypothesis of climate modelers inspired my accountant geologist Sara Khawaja (co-observes with geologist Claire Samson) to find evidence in the Venetian rocks for this proposed climate change phenomenon.
Since the early 1990s, my Carleton University research team – and most recently my Siberian team at Tomsk State University – have been mapping and interpreting the geographical and tectonic history of the Earth’s notable sister planet.
The Soviet Venera and Vega missions of the 1970s and 1980s landed on Venus and took pictures and evaluated the rock formation, before landers failed due to high temperatures and pressures. However, our most comprehensive view of the surface of Venus was provided by NASA’s Magellan spacecraft in the early 1990s, which used radar to view the level of the Gadrad cloud and produce detailed images of more than 98% of Venus’s surface.
Visualization of the surface of Venus produced by radar in the Magellan spacecraft.
Ancient rocks
The search for geographical evidence of the phenomenon of great climate change led us to focus on the oldest type of rock on Venus, called Tesrai, which is indicative of a complex appearance, a long, complex geological history. We thought that these most ancient rocks have the best chance of preserving evidence of water erosion, which is such an important process on Earth and must have occurred on Venus before the great event of climate change.
Given the weak resolution alt altitude data, we used indirect technology to try to identify the ancient river valleys. We showed that small lava flows from the surrounding volcanic plains, filling the valleys in the margins of Tessera.
Surprisingly, these Tessera Valley patterns were similar to river flows on Earth, leading to our suggestion that these Tessera valleys were formed by the erosion of rivers during this period with Earth-like atmospheric conditions. My Venus research groups at Carleton and Tomsk State Universities study the Tessie lava flow for any geographical evidence of transition to extremely hot conditions.
The first feature on Venus, known as Earth-based radar, was a piece of Alpha Regio with a topographic upward surface of Venus. Image by NASA-JPL.
Equality of the Earth
To understand how a volcano on Venus can cause such a change in weather, we can look at the history of the Earth for analogues. We can find similarities in super explosions like the last eruption in Yellowstone 630,000 years ago.
But such volcanoes are smaller than a large volcanic region (LIP) that occurs in about 20-30 million years. The events of these explosions could release enough carbon dioxide to bring about a catastrophic climate change on Earth, including mass extinction. To give you a sense of scale, consider that the smallest LIP produces enough magma to cover all of Canada up to a depth of about 30 feet (10 m). The most well-known LIP has produced enough magma to cover the size of Canada to a depth of about 5 miles (8 km).
LIP on Venus Analogs consist of individual volcanoes up to 0000 miles (km00 km), extensive lava channels reaching up to 300 miles (, 000,000 km), and there are also associated cracking systems – Where the crust is pulling – up to 6,000 miles (10,000 km) long.
If the LIP. The style volcano was the cause of the great climate change event on Venus, so could there be a similar climate reversal on Earth? We can imagine a scenario of many millions of years in the future when many LIPs will be visible at the same time. The randomly formed Earth could change into such a fugitive atmosphere, leading to conditions like the current Venus.
Richard Ernst, Scientist-in-Residence, Earth Science, Carleton University (also Professor of Tomsk State University in Russia), Carleton University
This article is republished Conversation Under Creative Commons License. Read the original article.
Bottom line: Venus has a surface temperature of 840 degrees F (450 degrees C) and is dominated by carbon dioxide in the atmosphere, which is 90 times denser than Earth. However, for most of its history, Venus had an Earth-like atmosphere, including oceans, rain, possibly ice, continents and plate tectonics, and more speculatively, perhaps even surface life. Then, less than a billion years ago, Venus’s atmosphere changed dramatically due to the fugitive greenhouse effect.
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