(ORDO NEWS) — Is there anything good about volcanoes? They can be violent, dangerous and unpredictable. For modern people, volcanoes are mostly an inconvenience, sometimes an intriguing visual picture, and sometimes a mortal danger.
But when there are enough of them, and when they are powerful and long-lasting, they can kill a planet inhabited by volcanoes. them.
Modern Venus is a burning hell. Temperatures rise above 464°C (850°F, 737°K), which Universe Today readers know is high enough to melt lead (and a spacecraft).
That’s why, of all the missions sent by Russia to the planet’s surface, only four managed to transmit images before they quickly succumbed to Venus’s extreme conditions.
But modern Venus may be very different from ancient Venus. Some studies show that ancient Venus had an atmosphere similar to that of ancient Earth.
There could also be a significant amount of water on the planet’s surface. It’s entirely possible that simple life once existed on Venus, but there isn’t enough evidence yet to prove or disprove this.
A new study shows that massive volcanic eruptions over an extended period of time could be causing the planet to change into what it is today. If simple life existed on ancient Venus, volcanism was its undoing.
The study also shows how powerful volcanic activity played a role in shaping the habitability of the Earth and how the Earth narrowly escaped the same fate as Venus.
Way of NASA‘s Goddard Institute is the lead author. Way has been researching Venus for many years and has authored and co-authored several papers on the planet, especially its ancient habitability.
“By studying the record of large igneous provinces on Earth and Venus, we can determine whether these events could have caused the current state of Venus,” Way said in a press release announcing the study.
The earth has experienced long periods of sustained volcanic eruptions in its history. Large igneous provinces (LIPs) are evidence of periods that can last hundreds of thousands of years, and maybe even millions of years.
LIPs can deposit over 100,000 cubic miles of rock to the surface. That’s enough to bury Texas half a mile deep.
On Earth, we know of many LIPs, and we know that over the past 500 million years they have coincided with periods of climate change and mass extinctions.
The study suggests that Venus was subject to massive volcanic eruptions. own, which created the modern atmosphere of Venus with its extreme temperatures and pressures.
In particular, it states that intense emissions over a period of just one million years have created a runaway greenhouse effect.
The unmanaged greenhouse effect is when the atmosphere prevents the planet’s heat from radiating into space. Without the possibility of cooling, the temperature rises to extreme levels, like in a greenhouse with all the vents closed.
The greenhouse effect of Venus is exacerbated by the apparent lack of plate tectonics. Plate tectonics allows heat from the planet’s interior to reach the surface due to the periodic opening of the mantle cover.
Also, during weathering and subduction, carbon dioxide enters the rocks from the atmosphere.
According to this work, our planet has experienced five mass extinctions, and all of them are associated with increased volcanic activity. (Some researchers point to a sixth mass extinction that is only just beginning as human activity increases species loss.)
The Chicxulub impact was the main cause of the Permian-Triassic extinction event that wiped out the dinosaurs, but volcanic activity also played a role.
While the Chicxulub dinosaur extinction is well known and widely popularized, volcanic activity was the main cause of extinction on Earth.
Life on Earth has been hit hard by powerful and sustained volcanic activity. But it has always recovered, and volcanoes have never caused a runaway greenhouse effect, while Venus still suffers from this effect. Who cares?
The scale of the eruptions had something to do with it. The surface of Venus is 80 percent covered in hardened volcanic rock. Sulfur in the atmosphere also indicates pronounced volcanic activity.
And there are fewer craters on the surface of Venus than expected, indicating heavy volcanic activity over the past few hundred million years.
But research should confuse someone. Although the Earth escaped the runaway greenhouse effect, it may have only narrowly avoided it.
Unraveling the history of volcanism, collisions and extinctions in the history of the Earth is difficult because the craters are being erased. There are scientific efforts being made to understand the conditions in the Earth’s mantle that lead to LIP, but this is also a challenging task.
The magmatic events that create LIPs are usually short-lived on a geologic time scale of less than 5 million. years in duration.
They can also be a series of pulses over several tens of millions of years. Although they eject a lot of rock to the surface, the chemicals they release into the atmosphere are responsible for the extinction.
A huge amount of CO 2 dramatically warmed the Earth’s atmosphere, and sulfur dioxide (SO 2 ) exacerbated the warming.
Toxic compounds such as hydrogen sulfide (H 2 S) and carbon monoxide (CO) are also produced by eruptions, but only in small amounts.
Earth’s volcanic activity is similar to that of Venus because the planets are “sister planets”. They are very close in size and are rocky planets in the inner solar system.
But the most important thing they have in common when it comes to volcanism is their bulk composition. Since they formed in the same region of the solar system, their composition is very similar.
In their study, the authors recreated the Earth’s volcanic history in a random simulation based on what is known about Earth’s volcanic activity and LIP.
“In one approach, we make a conservative estimate of the rate at which sets of near-simultaneous LIPs (pairs, triplets, and quartets) occur in a random history, statistically the same as on Earth,” the authors write.
“We found that LIPs closer in time than 0.1 to 1 million years are likely; significantly, this is less than the time that LIP’s terrestrial effects on the environment are known to persist.”
This means that LIP events overlap, and before the planet has time to remove the CO 2 released into its atmosphere from one event, another is busy releasing more.
Put them together and you have a runaway greenhouse effect. Individual LIPs in different parts of the globe, even under the oceans, exacerbate the effect.
A key part of their research concerns variability. Are LIPs related to each other in a causal relationship? This is important because if the level of LIP is variable, then it increases the likelihood of overlap or simultaneous events, which can contribute to an uncontrolled greenhouse effect.
“How will LIP level variability over time affect the odds for simultaneous events?” authors write.
“In times of increased speed, the probability of simultaneous events is higher than for average speed. On the other hand, during times of reduced speed, this probability decreases compared to the average. It is not clear which of these effects predominates.”
An interesting point in all of this concerns the longest LIPs on Earth. The longer one lasts, the more likely it is to overlap the other.
“[We] find that there is approximately a 30 percent chance that the largest LIP in Earth’s recorded history will overlap with a similarly sized (by area) event.
Multiple simultaneous LIPs could be important factors in the transition from a serene habitable surface to a greenhouse state for terrestrial worlds, assuming they have terrestrial geochemistry and mantle convection dynamics,” the paper says.
There is a moment when it all falls apart. While we have reasonably complete and reliable data on Earth’s LIP, we have nothing similar for Venus. But the study shows that even in the absence of detailed data, it is likely that Venus suffered from overlapping LIPs that led to its death.
Fortunately, upcoming missions to Venus will open up this investigation with more precise data.
The Venus VERITAS Mission (Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy) is an orbiter under development by NASA.
Its launch date has yet to be set, but it will be a three-year mission to acquire high-resolution images of the surface of Venus using radar and near-infrared spectroscopy.
It will provide detailed information on the history of the planet’s impact, volcanism, geochemistry and more.
The DAVINCI (Noble Gas Exploration, Chemistry and Imaging in the Deep Atmosphere of Venus) mission is also a NASA mission, but will have an atmospheric probe with it. with an orbiter. Once scientists have more information about Venus’s atmosphere and surface, they can begin to unravel the planet’s past.
“The main goal of DAVINCI is to narrow down the history of water on Venus and find out when it may have disappeared. disappeared, which provides more information about how Venus’s climate has changed over time,” Way said.
Both DAVINCI and VERITAS will launch in the late 2020s, with DAVINCI launching first.
ESA is also planning an orbital flight to Venus. It’s called EnVision and is due to launch in the early 2030s. EnVision will also study Venus’s atmosphere, but will dig deeper using its toolbox to study the planet’s internal structure.
These results will also play a role in understanding exoplanets. Exoplanets are a growing area of research, and the James Webb Space Telescope is beginning to provide better data on exoplanet atmospheres.
But it will be difficult for scientists to interpret the JWST results without better general models, and a more detailed understanding of our sister planet’s history will certainly improve our models of planetary atmospheres.
For some reason, the Earth remains habitable for billions of years, while Venus is in a much worse position. If there was once an ancient, simple life on Venus, then it has long been gone.
(I apologize to people who think that life can continue in the clouds of Venus.)
Although we may never have A full understanding of all the factors that made the Earth and Venus so different from each other clearly played a role in volcanic activity. Once VERITAS, DAVINCI, and EnVision do their thing, we will be able to understand the diverging path of Venus in more detail.
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