From Newsgroup: alt.fan.heinlein

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 havenrCOt 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 rCo why did life take so long to
move beyond simple organisms?

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

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

Early in EarthrCOs history, simple organisms formed in the ocean, but
humanity rCo an advanced civilization capable of communicating across
outer space rCo couldnrCOt exist if ancient life hadnrCOt 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 wasnrCOt 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, theyrCOre 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 donrCOt know for sure whether distant solar systems feature planets
with plate tectonics rCo current space telescopes donrCOt 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
rCLIn the original formulation, this factor was thought to be nearly 1, or 100% rCo that is, evolution on all planets with life would march forward
and, with enough time, turn into an intelligent civilization,rCY Stern
said. rCLOur perspective is: ThatrCOs not true.rCY

Indeed. Their math reduces the percentage of these planets that develop
ACCs to just 0.003% at minimum and 0.2% at maximum rCo 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 rCo 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 itrCOs
perfectly understandable why we donrCOt 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 planetrCOs fragmented, unruly, and shifting upper crust.

Learn More:

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

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

Share this:
Click to share on Facebook (Opens in new window)Click to share on
Twitter (Opens in new window)Click to share on Reddit (Opens in new window) Like this:
CATEGORIESASTRONOMY
TAGSDRAKE EQUATION, EARTH SCIENCE, FERMI PARADOX, PLATE TECTONICS
One Reply to rCLPlate Tectonics Might Only Occur on 0.003% of Planets.
That Makes Earth Very Special Indeed.rCY
Urban |ahlin
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?

Log in to Reply
Leave a Reply
You must be logged in to post a comment.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Post navigation
Previous Post
PREVIOUS
Alpha Centauri Could Have a Super Jupiter in OrbitNext Post
NEXT
A Concentrated Beam of Particles and Photons Could Push Us to Proxima
Centauri
Privacy Policy Proudly powered by WordPress

--- Synchronet 3.21d-Linux NewsLink 1.2