Paleo Peach Pits

Domesticated peaches

Scientists have discovered fossilized peach pits in southwest China. The fossil endosperms date to more than 2.5 million years ago ― ancient pits resembling pits from today's domesticated peaches.

Prehistoric ecological systems are imagined and hypothesized from terrestrial and aquatic plant fossils by paleobotanists. From the scientific disciplines of paleobotany and paleobiology, it's possible to explore the evolutionary history and interconnectedness of living organisms.

Earth is a vast cemetery where the rocks are tombstones on which the buried dead have written their own epitaphs.
― Louis Agassiz

Macrofossils, microfossils, trace fossils, and DNA and RNA samples are studied for clues and connections to present day organisms.

Fossilized peach pit
source: Tao Su

This finding suggests that peaches developed through natural selection long before homo sapiens domesticated peaches.

The domestication of the peach likely occurred some time after homo sapiens appeared some 200,000 years ago.

It's plausible that extinct hominid species like homo erectus, whose earliest fossil record dates back to about 1.9 million years ago, might have eaten peaches similar to the ones we eat today.

Life is better than death, I believe, if only because it is less boring, and because it has fresh peaches in it.
― Alice Walker, from Home Girls: A Black Feminist Anthology

REFERENCES

• Eat a paleo peach: First fossil peaches discovered in southwest China, Science Daily, 1 December 2015.
• Home Girls: A Black Feminist Anthology, by Barbara Smith, et. al., Rutgers University Press 2000.
• Paleobotany, Wikipedia.
• World's Oldest Fossil Peaches Found In China, by Janet Fang, 3 December 2015.

El Niño

The strongest El Niño since 1997-98 will likely emerge as 2016 unfolds. The 2015-16 El Niño is expected to impact the distribution, intensity, and frequency of precipitation, tropospheric ozone, and wildfires around the world.

NASA satellites have been monitoring the impact of El Niños over the past 15 years.

Deviation from mean surface water temperatures
17 December 2016
source: NOAA

El Niños occur when equatorial Pacific Ocean temperatures warm up over a prolonged period of time. NOAA defines this period as a 3-month increase in the mean surface water temperature of 0.9 °F (0.5 °C) or more in the east-central tropical Pacific.

Increased surface water temperatures feed heat and moisture transport into the atmosphere by intensifying convection. Convection occurs as heat from the ocean warms the air as it flows over the ocean surface. The warmer air expands, becomes less dense, and rises. This process creates a conduit of heat and moisture that fuels storms.

Contrasting higher than mean temperature deviations in an El Niño event, a La Niña event is characterized by a lower than mean temperature deviations.

Scientists analyze data to determine how it fits with reasonably well-understood physical models of some aspect of a weather system whether it's convective heat flow, fluid transport, gas transport, or other phenomena. Weather systems are notoriously complex. Weather has far-reaching, often unforeseen impacts.

"Big whirls have little whirls,
That feed on their velocity;
And little whirls have lesser whirls,
And so on to viscosity."
― Lewis Fry Richardson

Storm swell attributed to 2002-03 El Niño
Ocean Beach, San Diego
source: PD Photo.org

REFERENCES

• El Niño, Wikipedia.
• El Niño Portal, NOAA.
• NASA Examines Global Impacts of the 2015 El Niño, NASA, 15 December 2015.
• Understanding El Niño, by Johan Bromwich, New York Times, 16 December 2015.

Breathing Planet

Humans recognize the period from about 1760 to 1840 as the industrial revolution where we transformed from hand-made to machine production.

Since the beginning of the industrial age, the mean concentration of atmospheric carbon dioxide has increased from 280 parts per million to 400 parts per million.

"We're running the most dangerous experiment in history right now, which is to see how much carbon dioxide the atmosphere... can handle before there is an environmental catastrophe."
― Elon Musk

Over the past year, NASA's Orbiting Carbon Observatory-2 has been collecting global measurements of atmospheric carbon dioxide:

Atmospheric carbon dioxide concentration
NASA's Orbiting Carbon Observatory-2

Carbon dioxide concentrations were much higher a half a billion years ago because Earth was a rocky planet bereft of carbon sequestrating plant life. During the Devonian period 420 to 360 million years ago, Earth's atmosphere underwent a 15-fold decline in carbon dioxide.

"The decline is thought to be primarily attributable to carbon sequestration caused by the evolutionary emergence of large forest trees." ― The Forest Primeval

Atmospheric carbon dioxide concentrations have been rising steadily since the industrial age:

Actual and projected atmospheric carbon dioxide concentrations
source: Hannes Grobe

Much, if not most of life on Earth has an existential and symbiotic relationship with Earth's atmosphere. Animals must inhale and exhale to maintain life. Trees must sequester atmospheric carbon to grow a woody skeleton.

The word respire comes from the old French respirer or the Latin respirare meaning:

‘breathe out,’ from re- ‘again’ + spirare ‘breathe.’

Earth is planet of respiration. Earth is a breathing planet like no other planet we know.

What we call ’I’ is just a swinging door, which moves when we inhale and when we exhale.
― Shunryū Suzuki

REFERENCES

• A Breathing Planet, Off Balance, NASA, 12 November 2015.
• Excitement Grows as NASA Carbon Sleuth Begins Year Two, NASA/JPL-Caltech, 29 October 2015.
• The Forest Primeval, GrokEarth, 21 November 2015.

Light and Dark

Light is life. The Sun is one star among a continuous and distinctive band of stars called the main sequence. Carl Sagan reminds us that when we look up at the night sky, each shinning star light is generated by nuclear fusion.

Fusion powers the stars.

Regions of star formation. Carina Nebula, the Eagle Nebula, and IC 2944.
source: ESO

The Sun like other stars, generates energy in its core by fusing hydrogen atoms into helium. The dense core of the Sun fuses 620 million metric tons of hydrogen per second.

The Sun gives us light. As it happens, light is a precious commodity.

...astronomers have been forced to confront the possibility that most of the universe is invisible, and that all the glittering chains of galaxies are no more substantial, no more reliable guides to physical reality, than greasepaint on the face of a clown.
― Dennis Overbye

Atoms are the stuff of stars and of starlight. Yet as chance would have it, atoms constitute a mere 5% of the universe by weight. Some 20% of the universe is made up of mysterious invisible particles called dark matter. An unknown form of energy called dark energy constitutes the remaining 70% of the universe.

Arctic light

Frank Olsen

“let me die
from having been drunk on
indigo skies, my liver...
overflowing with stars.”
― Sanober Khan

REFERENCES

• Cosmos, by Carl Sagan, Random House, 1980.
• Stalking the Shadow Universe, by Dennis Overbye, New York Times, 16 July 2014.
• Turquoise Silence, by Sanober Khan, Cyberwit, 2015.

Soil Underfoot

16th century polymath Leonardo da Vinci observed, "We know more about the movement of celestial bodies than about the soil underfoot."

That da Vinci recognized our existential blindspot five hundred years ago is remarkable given soil scientists now warn us that Earth's soil is disappearing at a greater rate than it can be replenished.

A cloak of loose, soft material, held to the earth’s hard surface by gravity, is all that lies between life and lifelessness.
― Wallace H. Fuller

Soil profile
source: USDA

Humus

The word human arrived into the English-speaking lexicon from the Latin humus which translates to earth and ground.

The modern word humus describes organic material resulting from the biodegradation of plants and animals that are transformed into fertile soil. Plants drop leaves, seeds, twigs, and other materials to the ground which, over time, decay into rich, dark humus that becomes topsoil.

The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no community, because without proper care for it we can have no life.
― Wendell Berry

Soil Loss

The United Nations designated 2015 as the International Year of Soils. The UN cautions that more than a third of Earth's soil is at risk.

Wallace Fuller's cloak of organic material ― all that lies between life and lifelessness ― is undergoing rapid loss or degradation because of water erosion, wind erosion, pollution, acidification and nutrient depletion.

We might say that the earth has the spirit of growth; that its flesh is the soil.
― Leonardo da Vinci

Germination
source: USDA

Humility

Humility is from humus,
meaning from-the-earth.
We are pinholes of light
delayed by nothing and
arriving unannounced
like the tiny sounds
of before and after

REFERENCES

• Earth Could Lose a Third of Its Topsoil, by Patrick J. Kiger, Discovery, 15 October 2015.
• Soils of the Desert Southwest, by Wallace H. Fuller, University of Arizona Press, 1975.
• Humility, by Bob MacNeal, Buckets of Wisdom, 8 June 2013, Saint Paul.
• Spotlighting humanity’s ‘silent ally,’ UN launches 2015 International Year of Soils, UN News Centre, 5 December 2014.
• The Unsettling of America: Culture and Agriculture, by Wendell Berry, Counterpoint 2004.

The Forest Primeval

The first stanza of Longfellow's poem Evangeline sets the stage for a primal forest:

This is the forest primeval. The murmuring pines and the hemlocks,
Bearded with moss, and in garments green, indistinct in the twilight,
Stand like Druids of eld, with voices sad and prophetic,
Stand like harpers hoar, with beards that rest on their bosoms.

As ancient fossil forests are unearthed, scientists gather clues about nascent plant life and the prevailing climatic conditions of the time.

Fossilized forests discovered around the world, dated as far back as 380 million years ago, provide insights into Earth's ever-changing atmospheric composition and the corresponding climate changes on Earth.

During the Devonian some 420 to 360 million years ago, the atmosphere underwent a 15-fold decline in carbon dioxide. The decline is thought to be primarily attributable to carbon sequestration caused by the evolutionary emergence of large forest trees.

Carbon sequestration rates vary by forest age, composition, and location, but today we know that a single tree can absorb carbon dioxide at a rate of 48 lb. per year.

The decline in atmospheric carbon during the Devonian period is posited to have spawned large-scale global cooling that led to a period of glaciation.

Sketch of the forest floor in ancient fossil forest near Gilboa, New York
Frank Mannolini, New York State Museum

Fossil plant-life discovered in Schoharie County, New York in the 1850s, in 1920, and again in 2010, included the Gilboa stumps cited as Earth's oldest trees.

It was like discovering the botanical equivalent of dinosaur footprints. But the most exciting part was finding out just how many different types of footprints there were. The newly uncovered area was preserved in such a way that we were literally able to walk among the trees, noting what kind they were, where they had stood and how big they had grown."
― William Stein, Binghamton University, 2010

Researchers have unearthed another forest with fossilized tree stumps preserved in place in Svalbard, a Norwegian archipelago in the Arctic Ocean. 380 million years ago, Svalbard was located near the equator.

Reconstructed drawing
Fossil forest, Svalbard

Since the Devonian period, plate tectonics has transported Svalbard to its current location in the arctic ocean.

"These fossil forests shows us what the vegetation and landscape were like on the equator 380 million years ago, as the first trees were beginning to appear on the Earth."
― Chris Berry, Cardiff University

By the phenomena of carbon sequestration, trees absorb structure-forming carbon from atmospheric carbon dioxide through photosynthesis.

"The evolution of tree-sized vegetation is the most likely cause of this dramatic drop in carbon dioxide because the plants were absorbing carbon dioxide through photosynthesis to build their tissues, and also through the process of forming soils."
― Chris Berry

Svalbard is also in the forefront of preserving plant diversity. One of the northernmost inhabited villages on Earth, Svalbard is the site chosen by the Norwegian government in 2008 for the Global Seed Vault. Secured in the permafrost, the Svalbard seed vault is the largest seed storage in the World.

"In some mysterious way woods have never seemed to me to be static things. In physical terms, I move through them; yet in metaphysical ones, they seem to move through me."
― John Fowles

REFERENCES

• Ancient fossil forest unearthed in Arctic Norway, Phys.org, 19 November 2015.
• Cardiff uni researchers help unearth ancient forest, BBC News, 19 November 2015.
• Evangeline, A Tale of Acadie, Henry Wadsworth Longfellow, 1847.
• Floor of Oldest Forest Discovered in Schoharie County, NY, New York Geological Survey, 1 March 2012.
• Lycopsid forests in the early Late Devonian paleoequatorial zone of Svalbard, Christopher M. Berry1 and John E.A. Marshall, Geology, 19 November 2015.
• Svalbard Global Seed Vault, Norwegian Government, February 2008.

Earthly Rotation

Like a whirligig Earth rotates on its own axis.

Primitive observers from the inhabited middle latitudes of Earth would've have mused about something we rarely contemplate:

The Sun rises in the East
The Sun sets in the West

Like most celestial phenomena, Sunrises and Sunsets occur over a repeatedly observable and predictable cycle. During one day, the Sun appears to follow a half-circular arc through the sky.

As observers of the night sky our ancestors would've also noticed that stars moves along a similar circular path.

Our ancestors might have reasonably believed that the bespeckled night sky was an extraterrestrial backdrop that rotates.

"Before we invented civilization our ancestors lived mainly in the open out under the sky." ― Carl Sagan

Whirling Southern Star Trails over ALMA by ESO

Ancient ancestral astronomers might have hypothesized a stationary Earth centered about a rotating backdrop of stars.

"Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth."
― Ptolemy, Almagest, a 2^nd century astronomical treatise

Today we know it's the Earth that's rotating on its axis that creates this illusion. How might we devise a model that matches our observations and proves the Earth is rotating?

Supporting Model

Foucault pendulum
at the North Pole
by Theresa Knott

A less intuitive but valid hypothesis is that the Earth is rotating on its own axis. Of course we know now that Earth rotates on its own axis, but we were helped by a model to clinch the deal of corroborating what others had observed for generations.

The classic model that helped prove Earth is rotating on its own axis is a simple experiment with a pendulum known as the Foucault pendulum.

Foucault Pendulum

The Foucault pendulum (pronounced foo-koh) was introduced in 1851 to visually demonstrate Earth's rotation. The experiment is named after French physicist Léon Foucault.

An experimental Foucault pendulum, commonly suspended 39–98 feet and freely swinging back and forth, will be visibly affected by Earth’s rotation.

Simulated pendulum rotation
by Dominique Toussaint

The affect is not visible after a few swings, rather becomes gradually visible by a matter of degrees over the course of a day.

To maintain the bob of a pendulum swinging in museum demonstrations, an electromagnetic or other drive is used, or the pendulum is manually restarted.

A pendulum day is the time needed for the plane of a Foucault pendulum to complete 360 degree rotation. The duration of a pendulum day is one day divided by the sine of the latitude.

"I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." ― Umberto Eco

REFERENCES

• But it moves! How we know the Earth rotates, Ethan Siegel,17 September 2010.
• Foucault pendulum, Wikipedia.
• Pale Blue Dot: A Vision of the Human Future in Space, Carl Sagan, Random House 1994.

Increasingly Earlier Life

Every creature inhabiting Earth, including newcomers like humans, represents an unbroken line to primitive carbon-based life present on Earth nearer and nearer to the planet's probable inception some 4.54 billion years ago.

Gnat encased in amber

"What we normally think of as 'life' is based on chains of carbon atoms, with a few other atoms, such as nitrogen or phosphorus."
— Stephen Hawking, from a 2008 lecture

Chains of carbon atoms are common to all living things.

Biogenic Substances

Biogenic substances contain carbon which is a recognized marker for living organisms. Such substances, in the form of constituents, or as secretions from plants or animals, embody biomolecules which are the building blocks of life.

coal & oil	geologic-age constituents that have undergone changes
chalk & limestone	geologic-age secretions (e.g., marine animal shells)
grass & wood	contemporary constituents
pearls, silk & ambergris	contemporary secretions

Improbable Life

That life-forming elements came from dying stars in the far reaches of the universe make life on Earth nearly incomprehensible, if not improbable.

I tell my students, with a feeling of pride that I hope they will share, that the carbon, nitrogen, and oxygen that make up ninety-nine per cent of our living substance were cooked in the deep interiors of earlier generations of dying stars. Gathered up from the ends of the universe, over billions of years, eventually they came to form, in part, the substance of our sun, its planets, and ourselves. Three billion years ago, life arose upon the earth. It is the only life in the solar system.
— George Wald, Harvard Biochemist ⁽¹⁾

olive-green zircon crystal
by Rob Lavinsky

Earliest Biogenic Substances

The earliest recorded biogenic substances on Earth gets incrementally pushed back as scientists find and analyze new artifacts.

Until recently, graphite detected in rock dated 3.8 billion years ago was the earliest known biogenic residue of life.

UCLA geochemists recently identified specks of biogenic carbon encased in undisturbed, crack-free zircon crystals from Western Australia.

This discovery pushes back the earliest biogenic residue some 300 millions years to 4.1 billion years ago. Thus it places the probable earliest life closer to the time when Earth was formed 4.54 billion years ago.

"Life on Earth may have started almost instantaneously. With the right ingredients, life seems to form very quickly."
— Mark Harrison, UCLA geochemist

REFERENCES

• 4.1 Billion Year Old Australian Zircon Contains Graphite of Biological Origin, Sci-News.com 20 October 2015.
• Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon, Elizabeth A. Bella, Patrick Boehnkea, T. Mark Harrison, and Wendy L. Maob, PNAS, 10.1073/pnas.1517557112, 14 October 2015.

⁽¹⁾ From speech given at an anti-war teach-in at the Massachusetts Institute of Technology, (4 Mar 1969) 'A Generation in Search of a Future', as edited by Ron Dorfman for Chicago Journalism Review, (May 1969)

Atacama Bloom

Atacama Desert

Perched on a plateau west of the Andes on the Pacific coast is the driest non-polar desert on Earth. The Atacama Desert is a 600 mile long strip of otherworldly terrain of rocky hillsides, salt lakes, sand, and ancient felsic lava flows.

The hyperaridity of the Atacama has existed for at least 3 million years. It's the oldest continuously arid land on Earth. A few weather stations in the Atacama have never recorded precipitation.

Mean rainfall ranges from 0.04 to 0.12 inches per year in the coastal towns of Arica and Iquique to 0.6 inches per year in the abandoned mining town Yungay.

"Don't think about what you've left behind" The alchemist said to the boy as they began to ride across the sands of the desert. "If what one finds is made of pure matter, it will never spoil. And one can always come back. If what you had found was only a moment of light, like the explosion of a star, you would find nothing on your return.
― Paulo Coelho, The Alchemist

This year the Atacama is experiencing a rare springtime bloom. The Garra de León or Lion's Claw is a stunning red flower that's blooming in the Atacama. The Garra de León is a plant species exclusive to the Atacama Desert.

Garra de León in bloom
by Tomás Cuadra Ordenes

Historically a significant Atacama Desert bloom occurs every 5-7 years, but unusual March and August rains this year have produced cumulative precipitation not seen in nearly 20 years.

"At the moment it is gently raining. Imagine these flowers tomorrow."
by Tomás Cuadra Ordenes

Uncharacteristic rains have spawned a profusion of flowers. Seeds have germinated that have lain dormant for many years.

Long before I ever saw the desert I was aware of the mystical overtones which the observation of nature made audible to me. But I have never been more frequently or more vividly aware of them than in connection with the desert phenomena.
— Joseph Wood Krutch (1893-1970)

REFERENCES

• Atacama Desert, Wikipedia.
• Flowers bloom in the Atacama desert – in pictures, The Guardian, 30 October 2015.
• In Images: Stunning Flower Fields of the Atacama Desert by Tia Ghose, 29 October 2015.
• The voice of the desert : a naturalist's interpretation by Joseph Wood Krutch, 1955.
• Twitter feed of Tomás Cuadra Ordenes.

One in the Sunbeam

From a creed steeped in sin and submission, grew an expansive creed of wonderment and awe. Naturalist and preservationist John Muir abandoned an evangelical upbringing to discover a god of nature.

That Muir was thus reborn, not from a life of sin to submission to the God of the Bible, but from a life of repression to revelation of the God of Nature, has left us the rich and inspiring legacy of his wilderness gospel.
― Mark R. Stoll

Inspired by the transcendence of the High Sierras, Muir wrote:

Mountains holy as Sinai. No mountains I know of are so alluring. None so hospitable, kindly, tenderly inspiring. It seems strange that everybody does not come at their call. They are given, like the Gospel, without money and without price. 'Tis heaven alone that is given away'.

Alpine meadow, boulders, and mountains in Humphries Basin
John Muir Wilderness, Sierra Nevada

For Muir the Sierras were a source of infinite well-being, awe, and wonderment. He described the deep calm and connection with a keen presence and awareness:

Here is calm so deep, grasses cease waving... Wonderful how completely everything in wild nature fits into us, as if truly part and parent of us. The sun shines not on us but in us. The rivers flow not past, but through us, thrilling, tingling, vibrating every fiber and cell of the substance of our bodies, making them glide and sing. The trees wave and the flowers bloom in our bodies as well as our souls, and every bird song, wind song, and; tremendous storm song of the rocks in the heart of the mountains is our song, our very own, and sings our love.

Folded rocks of Sevehah Cliff on the trail up Convict Canyon
John Muir Wilderness, Sierra Nevada

Of the resonance and oneness one experiences in the transcendence of nature, Muir wrote:

The Song of God, sounding on forever. So pure and sure and universal is the harmony, it matters not where we are, where we strike in on the wild lowland plains. We care not to go to the mountains, and on the mountains we care not to go to the plains. But as soon as we are absorbed in the harmony, plain, mountain, calm, storm, lilies and sequoias, forests and meads are only different strands of many-colored Light-are one in the sunbeam!


REFERENCES

• God and John Muir: A Psychological Interpretation of John Muir's Life and Religion, Mark R. Stoll, Sierra Club.
• Mountain Thoughts, John Muir, Sierra Club. Note: Mountain Thoughts written by Muir during the 1870s, were collected by Linnie Marsh Wolfe and published in John of the Mountains, 1938.
• The New Holy Wars: Economic Religion Versus Environmental Religion in Contemporary America, Robert H. Nelson, Penn State University Press, 2010.

Tongue of the Hummingbird

Exposed tongue of a
black-throated mango
photo: Dr. Kristiina Hurme

A hummingbird's feeding mechanism is a rapier-like bill protecting a tongue that has adapted to extend deep into flowers to drink pools of sugar-rich nectar.

Conventional wisdom among ornithologists held that the hummingbird's tongue used capillary action to draw in nectar. Capillary action describes liquid flowing into narrow spaces due to intermolecular forces, rather than some external forces like gravity.

This past summer, while hummingbirds in North America were gathering nectar in preparation for their migratory journey to equatorial locales, evolutionary biologist and functional morphologist Alejandro Rico-Guevara published the results of a study that suggests the hummingbird's tongue acts like an elastic micro-pump.

Rico-Guevara observed that hummingbirds can draw nectar from a flower in less than a second which, he reasoned, was much too quick to be attributed to the wicking action of intermolecular forces.



Rico-Guevara's slow-motion video posted on YouTube by Science News (above) shows a hummingbird repeatedly extending its tongue into a red drink.

The hummingbird's tongue acts like an elastic micropump.

Rico-Guevara's study suggest that the hummingbird's tongue is compressed as it approaches the nectar, then becomes plump as the nectar rapidly hydrates grooves in the tongue.

And the humming-bird that hung
Like a jewel up among
The tilted honeysuckle horns
They mesmerized and swung
In the palpitating air,
Drowsed with odors strange and rare.
And, with whispered laughter, slipped away
And left him hanging there.
― James Whitcomb Riley

REFERENCES

• How hummingbirds' tongues work | Science News, YouTube, 18 August 2015.
• Hummingbird, Wikipedia.
• Hummingbird tongues are elastic micropumps, Alejandro Rico-Guevara, Tai-Hsi Fan, Margaret A. Rubega Proc. R. Soc. B 2015 282 20151014; DOI: 10.1098/rspb.2015.1014. Published 19 August 2015.
• Hummingbird tongues are way weirder than we thought, Rachel Feltman, Speaking of Science, Washington Post, 19 August 2015
• Hummingbird tongues may work like micropumps: How nectar rises through specialized grooves has inspired debate, Susan Milius, Science News, 18 August 2015.

Autumnal

As Earth orbits the Sun, it rotates on an axis tilted at 23.5 degrees. Accordingly, on its yearly journey, parts of Earth receive proportionally fewer hours of sunlight.

"Autumn seemed to arrive suddenly that year. The morning of the first September was crisp and golden as an apple."
― J.K. Rowling, Harry Potter and the Deathly Hallows

Earth's tilt relative to the Sun creates our seasons. As we move around the sun, the position of each hemisphere in relation to the Sun changes. Today we in the northern hemisphere are well underway tilting away from the sun, shortening the days and lengthening nights.

	Northern Hemisphere	Southern Hemisphere
June Solstice	Tilted towards the Sun → Summer	Tilted away from the Sun → Winter
December Solstice	Tilted away from the Sun → Winter	Tilted towards the Sun → Summer

As parts of Earth are illuminated by fewer hours of sunlight, days are shorter and nights are longer. The temperature drops. Autumn arrives, then in time, winter follows.

Trees respond to fewer hours of sunlight by generating less and less chlorophyll.

Intercity Bridge / Ford Parkway Bridge / 46th St Bridge over the Mississippi River

Chlorophyll in leaves enables trees to absorb and convert sunlight energy into sustenance via photosynthesis.

When chlorophyll (green) production stops, carotenoid (yellow, orange, brown) in the leaves become visible. Carotenoids are pigments synthesized by plant life. Reddish leaves are determined by temperature and cloud cover. Many consecutive warm autumn days and cool non-freezing nights produce anthocyanin (red) causing a reddish colors in leaves because of the sugar produced.

AUTUMNAL

Pale amber sunlight falls across
The reddening October trees,
That hardly sway before a breeze
As soft as summer: summer's loss
Seems little, dear! on days like these.

Let misty autumn be our part!
The twilight of the year is sweet:
Where shadow and the darkness meet
Our love, a twilight of the heart
Eludes a little time's deceit.

Are we not better and at home
In dreamful Autumn, we who deem
No harvest joy is worth a dream?
A little while and night shall come,
A little while, then, let us dream.

Beyond the pearled horizons lie
Winter and night: awaiting these
We garner this poor hour of ease,
Until love turn from us and die
Beneath the drear November trees.

― Ernest Dowson, The Poems and Prose of Ernest Dowson

REFERENCES

• Earth Rhythms, GrokEarth, 13 October 2012.
• What Causes Seasons, dateandtime.com.
• Why do Leaves Change Color, dnr.wi.gov.

Platypus to Puffball

Family tree of Earth's lifeforms

A family tree of Earth's lifeforms, some 2.3 million named species thus far, was recently published in draft form on opentreeoflife.org.

The circular tree of life compiled on opentreeoflife.org traces back 3.5 billion years ago to the beginning of life on Earth.

A tree of life, or phylogenetic tree, is typically a branching diagram that resembles a tree found in nature.

The lines or branches on a phylogenetic tree represent evolutionary relationships ― from platypus to puffball.

The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth.
― Charles Darwin, Origin of Species, Chapter IV

Branching relationships are derived from an organism's physical or genetic characteristics. Microbiologist Carl Woese proposed the tree of life shown below based on RNA data.

Phylogenetic tree scientific names

source: Eric Gaba, NASA Astrobiology Institute

The human species falls under the kingdom of animalia (shown in brown lines above) in the eucarya branch (cf. Human Classification in Know thy Tribe).

Charles Darwin found the tree to be a suitable metaphor to represent evolutionary relationships:

"The green and budding twigs may represent existing species; and those produced during former years may represent the long succession of extinct species. At each period of growth all the growing twigs have tried to branch out on all sides, and to overtop and kill the surrounding twigs and branches, in the same manner as species and groups of species have at all times overmastered other species in the great battle for life. The limbs divided into great branches, and these into lesser and lesser branches, were themselves once, when the tree was young, budding twigs; and this connexion of the former and present buds by ramifying branches may well represent the classification of all extinct and living species in groups subordinate to groups. Of the many twigs which flourished when the tree was a mere bush, only two or three, now grown into great branches, yet survive and bear the other branches; so with the species which lived during long-past geological periods, very few have left living and modified descendants. From the first growth of the tree, many a limb and branch has decayed and dropped off; and these fallen branches of various sizes may represent those whole orders, families, and genera which have now no living representatives, and which are known to us only in a fossil state. As we here and there see a thin, straggling branch springing from a fork low down in a tree, and which by some chance has been favoured and is still alive on its summit, so we occasionally see an animal like the Ornithorhynchus or Lepidosiren, which in some small degree connects by its affinities two large branches of life, and which has apparently been saved from fatal competition by having inhabited a protected station. As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever-branching and beautiful ramifications."
― Origin of Species, Chapter IV

Intelligent Life

Asked in a NOVA episode about the prospect of finding intelligent life somewhere beyond Earth's biosphere, cosmologist Neil deGrasse Tyson speculates that finding intelligent extraterrestrial life seems unlikely. Tyson draws a distinction between human intelligence ― characterized by perception, consciousness, self-awareness, and volition ― and the mechanisms needed to survive and proliferate.

I think that intelligence is such a narrow branch of the tree of life—this branch of primates we call humans. No other animal, by our definition, can be considered intelligent. So intelligence can't be all that important for survival, because there are so many animals that don't have what we call intelligence, and they're surviving just fine.
― Neil deGrasse Tyson

Life might exist beyond our life-raft in the biosphere. Tyson muses that the search for extant life is more likely to turn up "anything that falls between single-celled bacteria and life that has some kind of interesting purpose or function to perform", rather than life with the intellectual capacity of humans.


REFERENCES

• A Conversation With Neil Tyson, Nova, 28 September 2004.
• Know thy Tribe, GrokEarth, 12 September 2015.
• Origin of Species, Charles Darwin, The Harvard Classics, 1909–14.
• Phylogenetic tree, Wikipedia.
• 'Tree of life' for 2.3 million species released, Phys.org, 19 September 2015

Super Blood Moon

The confluence of three celestial phenomena happen tomorrow evening:

• a full moon;
• a supermoon; and
• a total lunar eclipse.

The last supermoon eclipse occurred in 1982.

Celestial phenomena are predictable because we have studied and understand planetary movements in the solar system.

Nothing comes close to the precision with which physics enables you to understand the world around you. It's the laws of physics that allow us to say exactly what time the sun is going to rise. What time the eclipse is going to begin. What time the eclipse is going to end.
― Neil deGrasse Tyson

Blood Moon
source: Anne Dirkse

Full moon

Tomorrow's full moon will be both a harvest moon and a blood moon.

A harvest moon is the full moon that falls closest to the fall equinox, which was last Wednesday.

A blood moons describes the red-tinted moon observed during a lunar eclipse. During a lunar eclipse, sunlight directed around the edges of the Earth refracts through Earth's atmosphere filtering out all but red, giving the moon its blood red tint.

Supermoon

Tomorrow's full moon will be a supermoon, or the full moon in perigee.

The moon orbits Earth in an elliptical path meaning that the distance between Earth and moon varies over an orbital cycle, giving us supermoons and micromoons.

A supermoon compared to a micromoon
source: Friends of NASA

Supermoons occur when the moon's orbital path transports it to the closest point to Earth. Micromoons occur when the moon is at its farthest point from Earth. A supermoon is about 31,000 miles closer to the Earth than a micromoon.

The closer proximity of a supermoon makes it appear 14% larger and 30% brighter.

The stronger gravitational pull of the supermoon causes wider variation in high and low tide levels.

Lunar Eclipse

Tomorrow's full moon will undergo a total eclipse.

Tomorrow night, the Earth will line up between the sun and the moon. The moon will gradually move into the shadow of the earth until it falls into darkness (i.e, a total eclipse).

Lunar eclipse
source: Luca

Under clear skies, tomorrow's lunar eclipse should be visible from longitudes stretching from the eastern Pacific to western Asia, including the Americans, Europe, and Africa.

Three things cannot be long hidden: the sun, the moon, and the truth.
― Gautama Buddha

The next supermoon eclipse occurs in 2033.

REFERENCES

• Rare supermoon eclipse comes Sunday, Jareen Imam, CNN, 25 September 2015.
• Super Blood Moon eclipse on night of September 27-28, Bruce McClure, EarthSky.
• Supermoon, GrokEarth, 12 July 2014.

Continental Volcano Chain

Geologists posit that hotspots, expressed on the ground surface as observable volcanic features, are fed by underlying super-heated plumes of mantle materials (shown in red).

The large-scale motion of Earth's lithosphere (shown in yellow) is known as plate tectonics.

Mantle hotspots remain stationary compared to the dynamic shifting of Earth's plates. As the lithosphere moves laterally, chains of volcanic islands in the ocean, or chains of continental volcanoes, form over millions of years.

A noted continental chain was created by the Snake River Plain-Yellowstone hotspot. The Snake River Plain-Yellowstone hotspot is the source of a 400 mile chain of volcanic features created over 15 million years. It extends from what is today the Idaho-Oregon border up intoYellowstone National Park in northwest Wyoming.

The Lava Creek eruption, the most recent significant volcanic event in the chain, occurred some 640,000 years ago causing the Lava Creek Tuff and the Yellowstone Caldera.

The longest continental chain, three times as long as the track caused by the Yellowstone hotspot, has recently been identified in Australia by a team of geologists.

Cosgrove Volcano Track

Geologists have recently identified the longest series of continental volcanoes, named the Cosgrove volcano track. The track spans 1,243 miles across eastern Australia (shown below). Geologists posit that as Australia moved north over a hotspot, volcanic features were created over the course of 33 million years.

Cosgrove volcano track

"We realized that the same hotspot had caused volcanoes in the Whitsundays and the central Victoria region, and also some rare features in New South Wales, roughly halfway between them."
― Dr. Rhodri Davies, Australian National University

Hotspots occur where rocks melt to create flowing magma. Heated by the hot core, fluid rock in the mantle rises and falls. Plumes of magma occasionally penetrate the crust to produce volcanoes. Over millions of years, continental plates move laterally over the hotspots thus creating a travel log expressed by volcanic features marking the surface of the Earth.

"Ultimately this new understanding may help us to reconstruct the past movements of continents from other hotspots."
― Dr. Nick Rawlinson, University of Aberdeen

REFERENCES

• Core Energy, GrokEarth, 5 September 2015.
• Hotspot, Wikipedia
• Lithospheric controls on magma composition along Earth’s longest continental hotspot track, D. R. Davies, N. Rawlinson, G. Iaffaldano & I. H. Campbell, Nature, 14 September 2015.
• What is a Hotspot, Oregon State University, Volcano World.
• World's longest continental volcano chain in Australia, Science News, 14 September 2015.
• Yellowstone Hotspot, Wikipedia.

Know thy Tribe

H O M O.   Nosce te ipsum

Carl Linnaeus published Systema Naturae in 1735. Linnaeus described humans (Homo) with the latin phrase nosce te ipsum which translates to know thyself.

Systema Naturae lists more than 10,000 species of plants and animals and introduced Linnaean taxonomy.

Linnaean taxonomy became the foundation for biological nomenclature and provides the hierarchical basis for how we classify animals, plants, bacteria and other organisms including ourselves, homo sapiens.

Human classification gets revised as we unearth more bones and fossils.

You are truly home only when you find your tribe.
― Srividya Srinivasan

Like others animals, the classification of homo sapiens is illustrated by a taxonomic chain that starts in the broad classification of the animal kingdom then gets increasingly specific before arriving at our genus and species homo sapiens.

Human Classification

Kingdom	Animalia
Phylum	Chordata (animals with a notochord; in fish, reptiles, birds and mammals, the notochord becomes the vertebral column)
Class	Mammalia
Order	Primates (lemurs, bush babies, tarsiers, monkeys, apes and humans)
Family	Hominidae (orangutans, gorillas, chimpanzees and humans)
Subfamily	Homininae (gorillas, chimpanzees and humans)
Tribe	Hominini (humans and our close extinct relatives)
Genus	Homo
Species	Sapiens

Homo naledi

Berger et al. 2015 

A new hominin species found in a cave in South Africa was announced last Thursday (Berger et al). The new species is named Homo naledi. Naledi means star in the local Sesotho language.
Naledi refers to the Rising Star Cave where the bones were discovered undisturbed on an earthen flow below a narrow crack in a limestone wall.

Naledi is a new member of our hominini tribe.

The collection of bones in a remote cave chamber suggests that early hominins intentionally placed their dead which is a behavior previously thought to be limited humans.

Tribe follows tribe, and nation follows nation, like the waves of the sea. It is the order of nature, and regret is useless.
― Duwamish Chief Seattle, 1854 Oration

REFERENCES

• Homo Naledi, New Species in Human Lineage, Is Found in South African Cave, by John Noble Wilfordspet, New York Times, 10 September 2015.
• What’s in a Name? Hominid Versus Hominin, Smithsonian magazine, 16 November 2011.
• When Indians became cowboys : native peoples and cattle ranching in the American West, by Peter Iverson, University of Oklahoma Press, 1994.

Core Energy

Using a three-dimensional supercomputer simulation that aggregated seismic wave pathways generated from 273 earthquakes over the past 20 years, geophysicists from Lawrence Berkeley National Laboratory recently mapped plumes of heat energy from Earth's interior:

Heat plumes at boundary between the Earth's
metal core and it's rocky mantle 1,800 miles
below ground.

Lawrence Berkeley National Laboratory
University of California, Berkeley

This visualization of the plumes of hot rock rising through the mantle correlate to hotspots around the planet where we observe the ongoing generation of chains of volcanic islands.

Geologists have long recognized the ongoing occurrences of terrestrial changes as Sir Archibald Geikie observed in his 1879 lecture to the Royal Geographical Society:

Looking back across the long cycles of change through which the land has been shaped into its present form, let us realise that these geographical revolutions are not events wholly of the dim past, but that they are still in progress. So slow and measured has been their march, that even from the earliest times of human history they seem hardly to have advanced at all. But none the less are they surely and steadily transpiring around us. In the fall of rain and the flow of rivers, in the bubble of springs and the silence of frost, in the quiet creep of glaciers and the tumultuous rush of ocean waves, in the tremor of the earthquake and the outburst of the volcano, we may recognise the same play of terrestrial forces by which the framework of the continents has been step by step evolved.
— Sir Archibald Geikie, lecture at the RGS, 24 March 1879

Structural Cutaway

source: kelvinsong

Earth's crust consists of oceans and continents.

Underlying the crust is the mantle which is about 1,800 miles thick.

The mantle consists of hot but solid rock. Below the mantle is the outer core which is a liquid layer of molten iron and nickel.

And many a fire there burns beneath the ground.
— Empedocles

The inner core is solid iron.

Terrestrial Change

Heated by the hot core, rock in the mantle rises and falls. Plumes of hot rock occasionally penetrate the crust to produce volcanoes. As Earth's crust moves laterally around the planet via plate tectonics, the hot stationary rock in the mantle penetrate the crust to generate chains of islands.

The Galapagos, Cape Verde, Samoa, Hawaiian, and Canary islands are examples of volcanic island chains created by Earth's crust moving laterally over stationary super-heated mantle rock.


REFERENCES

• CT scan of Earth links deep mantle plumes with volcanic hotspots, Science Daily, 2 September 2015.
• Structure of the Earth, Wikipedia.
• Today in Science quotations.