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Big DEAL !!
from https://www.universetoday.com/167659/plate-tectonics-might-only-occur-on-0-003-of-planets-that-makes-earth-very-special-indeed/

Plate tectonics: Image Credit: NASA/Goddard Space Flight Center
Scientific Visualization Studio
POSTED ONJULY 2, 2024 BY SCOTT ALAN JOHNSTON
Plate Tectonics Might Only Occur on 0.003% of Planets. That Makes Earth
Very Special Indeed.
Plate tectonics, oceans, and continents might just be the secret
ingredients for complex life on Earth. And if these geological features
are rare elsewhere in the universe, then perhaps that explains why we
haven’t yet discovered intelligent alien life. New research from
American and Swiss Earth scientists suggests that these ingredients
represent missing variables in the famous Drake equation, devised more
than half a century ago to estimate the chances of finding advanced civilizations in our galaxy. Including these new variables could
completely rewrite the probability of detecting intelligent life in the
Milky Way.

The impetus for this research, with its galaxy-spanning implications,
began with a mystery right here at home – why did life take so long to
move beyond simple organisms?

“Life has been around on Earth for about 4 billion years, but complex organisms like animals didn’t appear until about 600 million years ago,
which is not long after the modern episode of plate tectonics began,”
said Robert Stern of the University of Texas at Dallas. “Plate tectonics really jump-starts the evolution machine, and we think we understand why.”

Stern and his collaborator, Taras Gerya of the Swiss Federal Institute
of Technology, propose that plate tectonics – the grinding movement of
the upper layers of the planet at long geologic time scales – helped
speed up the transition to complex life.

Early in Earth’s history, simple organisms formed in the ocean, but
humanity – an advanced civilization capable of communicating across
outer space – couldn’t exist if ancient life hadn’t transitioned to
land. Vast, resource-rich continents were therefore a vital prerequisite
for what Stern and Gerya call Active Communicative Civilizations (ACCs)
like humanity to develop. But that alone wasn’t enough: the continents
needed to move.

The geologic record on Earth suggests that plate tectonics accelerated evolution on land through five distinct processes: it increased the
supply of nutrients; sped up the oxygenation of both the atmosphere and
the ocean; tempered the climate; caused a high turnover rate of habitat formation and destruction; and offered non-catastrophic environmental
pressure that forced organisms to adapt.

The end result of all these environmental pressures: us.

If Stern and Gerya are right, plate tectonics were a requirement for
eventual innovations like the wheel, the smartphone, and the Apollo program.

And for other civilizations in the galaxy to develop similar
technological marvels, perhaps their planets need plate tectonics too.
But as far as we know, they’re rare.

Earth is the only planet in our solar system to feature plate tectonics. Volcanism exists on some other worlds, like Venus, Mars, and Io, but
these worlds have a singular solid shell, rather than multiple moving
plates. Similarly, ocean worlds like Enceladus and Europa are bound
within an icy coating, forbidding any hypothetical life there from transitioning to land.

We don’t know for sure whether distant solar systems feature planets
with plate tectonics – current space telescopes don’t have the
resolution to make such determinations. But knowing that they might not
enables a more accurate version of the Drake equation.

There are two essential factors proposed in the revised equation: the
fraction of habitable exoplanets with large continents and oceans, and
the fraction of those that have plate tectonics lasting more than 500
million years.

This version is much more nuanced than the original Drake equation,
which simply took into account the fraction of habitable planets on
which intelligent life had developed.


The Drake Equation, a mathematical formula for the probability of
finding life or advanced civilizations in the universe. Credit:
University of Rochester
“In the original formulation, this factor was thought to be nearly 1, or
100% — that is, evolution on all planets with life would march forward
and, with enough time, turn into an intelligent civilization,” Stern
said. “Our perspective is: That’s not true.”

Indeed. Their math reduces the percentage of these planets that develop
ACCs to just 0.003% at minimum and 0.2% at maximum – a far cry from the original 100%.

When put together with all the other factors of the Drake Equation:
number of stars formed annually, number of those stars with planets,
number those planets that are habitable, number of those habitable
planets with life, number of civilizations on those planets sending out detectable signals, and how long they send out the signals – well, the chances of finding intelligent alien life shrink considerably.

The implications of the original Drake equation were that ACCs should be common, and we should see them everywhere. But including plate tectonics
in the equation changes the result, and makes it clear that it’s
perfectly understandable why we don’t see ET all across the galaxy.

So intelligent alien life might be rarer than anyone thought. And Earth
may be more special than we knew. All thanks to our planet’s fragmented, unruly, and shifting upper crust.

Learn More:

Amanda Siegfried, “Geoscientists Dig into Why We May Be Alone in the
Milky Way.” University of Texas at Dallas.

Robert Stern and Taras Gerya, “The importance of continents, oceans and
plate tectonics for the evolution of complex life: implications for
finding extraterrestrial civilizations.” Nature Scientific Reports.

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CATEGORIESASTRONOMY
TAGSDRAKE EQUATION, EARTH SCIENCE, FERMI PARADOX, PLATE TECTONICS
One Reply to “Plate Tectonics Might Only Occur on 0.003% of Planets.
That Makes Earth Very Special Indeed.”
Urban Åhlin
JULY 3, 2024 AT 9:57 AM
I am highly sceptical to this conclusion. Where have they gotten the
number 0.003% from? We have yet to observe any exoplanets up close or in
so high resolution that we can say anything of their surface, let alone
their internal structure. So how can we possibly know anything of their
plate tectonics?

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