Saturday, January 23, 2016

{4} Evolution-Considering Deep Time and a Couple Big Breaks

The poetry of evolution... we are born into a flowing river of time on a continually changing planet.  Today will never come again and tomorrow is the accumulation of all the days that came before.  

To understand the reality of what we are doing to our atmosphere and planet requires an appreciation of four and a half billion years worth of evolution happening one day at a time.  Step by step changes created this awesome biosphere most everyone seems to be taking oh so for granted these days.

To better appreciate evolution we need to understand "deep time" so I've included a couple short videos that try conveying the vast distance of time between us and then.

Very early in our Earth's life there were two key events that transformed our planet from just another conglomeration of rocks orbiting a star, to a place brimming with potential.

First there was the formation of our moon, followed by the cascading physical consequences of its extraordinary gravitational pull on Earth.  Since then, the moon has helped protect us from meteor collisions; helped stabilize the wobble of Earth's axis and our seasons.  In the early days, the near-in moon caused tremendous tidal churning, not only of the oceans, producing unimaginable waves accompanied by immense winds, but also of the Earth's crust and core itself.  

The ocean's early tidal waves hit proto continents like nothing we can image.  Back then (actual, like 90% of Earth's history) the only thing sculpting Earth was tectonics, gravity, water, wind and temperatures.  There was mountains and vast expanses of braided-stream tidal plains on growing continental shelves, that and huge endless oceans.  

Realize the early moon was very close, orbiting around a much faster spinning Earth.  With time the moon receded, all that drag slowed down Earth's orbit and the tides became increasingly toned down.

Still, imagine those early eons with intense currents and "tidal bore waves" that were dozens of meters tall, (if not hundreds, very early on), raging in and out for hundreds of miles, twice daily.  That was right here on this planet, it's an awesome thing to mull-around in your mind.  Almost like a global crushing plant in the first stages of mineral processing and refining.

Then there was the early formation of Earth's protective geomagnetic (force) field, that protects Earth from harsh Solar Wind.

Happy Learning

Deep Time

For a quick overview see:

Exploring Origins - a timeline of life's evolution

I was surprised at how few YouTube videos do a good job of tackling the subject.  Here are two decent efforts.  The first one compares the timeline to the 365 days in a year; the second uses the distance from L.A to N.Y. 2,450 miles.  If you don't like the music, mute it, there's no narrative.

4.6 Billion Years in the making. Our wonderful world 
yumorganics  |  3:46 min

Putting the history of Earth into perspective 
BI Science  |  3:39

Our Moon

Very early in Earth's life, during the final stages of formation by accretion, it received the biggest impact of all, namely Theia, (or perhaps it was a couple smaller theia's), which subsequently produced a new Earth; radically changing the planet's core as well as its atmosphere; and producing the moon with it's extraordinary influence on Earth from that moment forward.

Giant Impact That Formed the Moon Blew Off Earth's Atmosphere
by Katia Moskvitch  |  |  October 01, 2013
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Without the Moon, Would There Be Life on Earth?
By driving the tides, our lunar companion may have jump-started biology--or at least accelerated its progression
By Bruce Dorminey on April 21, 2009 | Scientific American
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If We Had No Moon
By Astrobio - Oct 29, 2007
The other crucial development was that our cooling Earth's (now Theia enriched) iron core, aided by the new moon's tidal forces, developed into an electromagnetic dynamo that produces our protective geomagnetic field.

Earth's Geomagnetic (force) Field

The easy versions:

What causes the Earth's magnetic field?
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Generation of the Earth's magnetic field
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Excellent data generated graphics.

Earth's Magnetism in HD 
Apparently Apparel  |  7:38

Published on Aug 18, 2012
Discovery channel HD presents a nice detailed explanation about the Sun and how it has a direct effect on Earth's magnetic field. Most of you will say "I knew this already" which a lot of people do, but this clip has the clearest explanation on the Sun and it's positive and occasional negative effects on the Earth, and the people. Worth watching.

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For a more exacting exploration:
Geomagnetic Reversals and excursions: The origin of Earth's magnetic field. 
Bruce Buffett  |  SETI Institute  |  1:00:20 
Published on Oct 16, 2015 
Palaeomagnetic observations offer important insights into the origin of Earth's interior, but a detailed reconstruction of the underlying dynamics is not feasible. A practical alternative is to construct a stochastic model for the time evolution of the dipole field. ... 
Dr. Buffet will explain how a physical interpretation of the stochastic models suggests that reversals and excursions are part of a continuum of time variations in Earth's magnetic field, arising from convective fluctuations in the core. Relatively modest changes the amplitude of convective fluctuations can produce large changes in reversal rates, including the well-known occurrence of superchrons lasting longer than 10 million years.
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A good cut-away graphic of Earth's core and the geomagnetic field at 1 minute in.

ESA's 'Swarm' Mission to Probe Earth's Magnetic Field 
Uploaded on Dec 18, 2010 
The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, and gain new insights into improving our knowledge of the Earth's interior and climate. 
The Swarm concept consists of a constellation of three satellites in three different polar orbits between 400 and 550 km altitude. High-precision and high-resolution measurements of the strength and direction of the magnetic field will be provided by each satellite. 
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'Magnetic' Discovery May Reveal Why Earth Supports Life and Mars Doesn't
by Charles Q. Choi, Live Science Contributor   |   July 30, 2015
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Earth's magnetic shield is much older than previously thought
An older geomagnetic field suggests an early start to plate tectonics
J. A. Tarduno, R. D. Cottrell, W. J. Davis, F. Nimmo, R. K. Bono. 
A Hadean to Paleoarchean geodynamo recorded by single zircon crystals. | July 30, 2015
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Earth's magnetic field provides vital protection
Scientific results prove the efficacy of Earth’s magnetic field in deflecting the solar wind and protecting our atmosphere.
By ESA, Noordwijk, Netherlands  |  Published: Tuesday, March 13, 2012

Wednesday, January 6, 2016
{1} Our Global Heat and Moisture Distribution Engine

Saturday, January 9, 2016
{2} Co-evolution of Minerals and Life | Dr Robert Hazen

Thursday, January 14, 2016
{3} Evolution of Carbon and our biosphere - Professor Hazen focuses on the element Carbon

Saturday, January 23, 2016
{4} Evolution-Considering Deep Time and a Couple Big Breaks

Saturday, February 6, 2016
{5a} The Most Beautiful Graph on Earth - A. Hessler

Sunday, February 7, 2016
{5b} Earth's Earliest Climate - By Angela Hessler

Sunday, February 14, 2016
{6} Evolution of Earth's Atmosphere - easy version

Thursday, February 18, 2016
{7} Our Global Heat and Moisture Distribution Engine, visualized

Friday, February 19, 2016
{8} Atmospheric Insulation Explained - appreciating our climate engine

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