Fine tuning specifics: Earth vs. Venus (Introduction)

by David Turell , Wednesday, November 23, 2022, 15:28 (731 days ago) @ David Turell

The planets are virtual twins. Why is Venus a basket case of greenhouse effect? Volcanism run amok:

https://www.sciencealert.com/volcanoes-may-have-transformed-venus-into-a-blistering-hel...

"Modern-day Venus is a blistering hellscape. The temperature rises above 464 °C (850 °F, 737 °K), which is, as Universe Today readers know, hot enough to melt lead (and spacecraft).

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"But modern-day Venus might be dramatically different from ancient Venus. Some research shows that ancient Venus had an atmosphere similar to ancient Earth's.

"The planet may also have had substantial quantities of water on its surface. It's possible that simple life existed on Venus at one time, but there's not enough evidence yet to prove or disprove that.

"A new study shows that massive volcanic eruptions over an extended period of time may be responsible for changing the planet into what it is today. If there was simple life on ancient Venus, volcanism was its doom.

"The study also shows how powerful volcanic activity has played a role in shaping Earth's habitability and how Earth only narrowly avoided the same fate as Venus.

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"Earth has experienced prolonged periods of sustained volcanic eruptions in its history. Large Igneous Provinces (LIPs) are the evidence for the periods, which can last hundreds of thousands of years – maybe even millions of years.

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"Venus's greenhouse effect is exacerbated by its apparent lack of plate tectonics. Earth's plate tectonics allows heat from the planet's interior to reach the surface by periodically opening the mantle blanket. (my bold)

"It also takes carbon dioxide out of the atmosphere and into rock via weathering and subduction.

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"Life on Earth suffered mightily from powerful and sustained volcanic activity. But it always recovered, and the volcanoes never caused a runaway greenhouse effect, while Venus suffers to this day from the effect. What's the difference?

"The scale of eruptions had something to do with it. Venus's surface is 80 percent covered with solidified volcanic rock. The sulphur in the atmosphere is also evidence of pronounced volcanic activity. And Venus' surface has fewer craters than expected, indicating abundant volcanic activity in the last few hundred million years.

"But the study should make anyone uncomfortable. Though Earth has avoided the runaway greenhouse effect, it may only have narrowly avoided it.

"Untangling the history of volcanism, impacts, and extinctions in Earth's history is challenging because craters get erased. There are scientific efforts to understand the conditions in Earth's mantle that lead to LIPs, but that's also a difficult task.

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"Earth's volcanic activity is similar to Venus's because the planets are "sister planets." They're very close in size and are both rocky planets in the inner Solar System (my bold)

"But the critical thing they share when it comes to volcanism is their bulk composition. Since they formed in the same region of the Solar System, they have very similar compositions. (my bold)

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"'[W]e find that the probability of the largest LIP in recorded Earth history overlapping with a similar-sized (in area) event is approximately 30 percent. Multiple simultaneous LIPs may be important drivers of the transition from a serene habitable surface to a hothouse state for terrestrial worlds, assuming they have Earth-like geochemistries and mantle convection dynamics," the paper states.

"There's a point where all of this diverges. While we have fairly complete and reliable data on Earth's LIPs, we don't have anywhere near that for Venus. But the research shows that, even with our lack of detailed data, it's likely that Venus suffered overlapping LIPs that led to its doom."

Comment: seemingly twins at their start they ended up differently. One with plate tectonics, one without. The authors note other differences (my bolds) but my point is this dumb luck or God's guidance? This is another firm aspect of fine-tuning.