Ergs

Namib Naukluft National Park, Namibia. (Photo by Michael Poliza)

Once again I have been thinking about the Namib Desert–the world’s oldest desert–which calls to me for reasons I cannot fully explain. I wrote about some of the Namib’s strange animals and plants…but one thing I did not mention was its ergs. This is because I did not know what an erg is, but today I looked it up and the concept is simultaneously horrifying and beautiful. An erg is a sea of wind-blown sand. This geographic feature is not unique to the Namib Desert—or indeed to planet Earth—but they do tend to be found only in vast & mighty deserts. Such a landscape is characterized by vast dunes—mountain-like sand hills composed of immense numbers of individual sand grains.

A sand dune in the Rub al Kali Desert

Geographers have seemingly fixed certain parameters on how large a sandbed must be to count as an erg—but I will let you look these up on your own—I think the word “sea” covers the scope of ergs. We are not talking about a child’s sandbox here.

Issaouane Erg, Algeria (photo from the International Space Station)

The word erg derives from an Arabic word “arq” which means dune landscape. The Rub al Kali Desert “the empty quarter” of Saudi Arabia is a vast erg—the world’s largest. There are a multitude of ergs throughout the Sahara (as seen on the map below) and they can also be found in central Asia, the middle of Australia, and the Atacama Desert (which I also really need to write about). Ergs are less common in North America than in Asia and Africa, but there a few notable examples mostly in the Sonoran Desert, but also including the unimaginatively named “Great Sand Dunes” in Colorado.

The geology of ergs is quite fascinating as the dominant agent of erosion and change is wind rather than water. When wind activity shapes the surface of the Earth (or another planet), geologists describe the varying sorts of erosion, deposition, and weathering as “Aeolian processes” in homage to the ancient Greek god of the winds who crops up in the Odyssey and the Aeneid. Ergs do not just feature great dunes but also strange sand sculpted rocks and dry river beds.

White Sands, New Mexico

As noted, ergs are not a phenomena exclusive to Earth, but can be found on other planetary bodies too (if they have silica and atmospheres). Ergs have been discovered on Mars where vast erg fields ring the polar caps. The Martian winds blow the ergs into bizarre patterns and shapes (usually I would say “otherworldly”, but that seems too pedestrian a word here). Venus also has ergs (discovered by the Magellan probe) and Cassini’s radar spotted huge parallel ergs on Saturn’s great moon Titan. Indeed ergs may be the dominant surface feature of Titan.

Martian Polar Dunes (photographed by the Mars Odyssey Spacecraft)

I have never been to an erg. There are none in Brooklyn (yet). However I would like to see one…although I admit to a certain amount of trepidation. They do not seem like places for life, and indeed they are among the most lifeless places on all of Earth. Ergs are beautiful but also terrible and dangerous. At least they should stay free of suburban sprawl for long enough for me to visit one (and it will probably be a very long time indeed before we cover the ergs of Titan with strip malls).

Erg Chebbi in Morocco (Bjørn Christian Tørrissen)

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The Rise and Fall of Cronus

Cronus

In Greek myth the Titan Cronus, was ruler the heavens and king of the gods prior to the ascent of Zeus. Cronus ruled over the golden age of humankind when suffering was unknown and death was but a gentle dream.  Yet there was a darkness behind the reign of Cronus, a terrible stain upon the sickle which was his emblem.  Even while Cronus ruled heaven, he knew that he would end as a maimed wretch cast down into the underworld. A dread augury had revealed that he would fall at the hands of a son more powerful than he–and his personal history convinced him the prophecy was sooth.

Cronus was the most powerful son of Uranus, the original god of the primordial heavens. At the beginning of all things Uranus ruled as king of the gods and the firmament–but Uranus was displeased by the Hekatonkheires, hundred handed monsters born to him by his spouse Gaia. Despite Gaia’s pleas, Uranus imprisoned these monstrous sons in the dark prison of Tartaros.  Incensed by the haughtiness of her spouse, Gaia crafted a great flint sickle from her own bones.  Only Cronus had sufficient ambition, nerve, and cruelty to wield the sickle.  He ambushed Uranus and cut him into bloody pieces.  Gods and monsters were born of the hewn apart body of Uranus.  Unfortunately for Gaia’s plans,  Cronus saw no reason to free the Hekatonkheires, the Cyclops (one eyed monsters), or the other “undesirables” Uranus had already locked away and thus he, in turn, incurred the wrath of Gaia.

Cronus devours one of his offspring (Peter Paul Rubens, 1636, oil on canvas)

Having committed such an act, Cronus could not rest easy with his own children.  Whenever his wife, the Titaness Rhea, bore a son or daughter he snatched the baby away and swallowed it whole.  The mighty immortal Olympians, Demeter, Hera, Hades, Hestia, and Poseidon all started their lives as prisoners in their father’s gullet. Just before Zeus was born, Gaia whispered a plan to Rhea.  Rhea dressed a stone in swaddling clothes and gave it to her husband in place of their newborn child.  Cronus gulped down the rock and was none the wiser.  The baby grew to adulthood tended by Nymphs and fed by the divine goat Amalthea. When Zeus had grown powerful he made allies with Gaia and he took a first wife, Mètis, the goddess of wisdom, deep thought, and cunning.  Mètis gave Cronus a purgative of wine and mustard which caused the Titan to hurl up the five fully grown siblings of Zeus.  Together the Olympians, in alliance with the various sorts of imprisoned monsters, made war on the Titans (except for Prometheus, who could see the future and joined Zeus).  This epic battle, the Titanomachy, reshaped the landscape of the world (particularly that of Thessaly), but when it was over, the Olympians were victorious.  Cronus was cast down and Zeus locked him in Tartarus along with the other Titans except for Prometheus (and strong Atlas—who suffered his own punishment).  Zeus incurred the wrath of Gaia for imprisoning the Titans, who were also her children, and she began plotting against him and bearing further monsters to end his reign.

The Battle Between the Gods and the Titans (Joachim Wtewael, 1600)

Thus Zeus became king of the gods, but prophecy whispered that he would one day be supplanted by a stronger son….

What about Cronus? In classical myth, gods are immortal. The maimed Cronus could not die.  In some traditions he was imprisoned for a time in Tartaros with his siblings.  Mystery cults asserted that he recovered some of his regal glory: the Greek dithyrambic poet  Pindar wrote of how Cronus was elevated to be ruler of Elysium, that portion of the underworld reserved for heroes. According to the Orphic poems, Cronus is imprisoned for eternity in the cave of Nyx.  In the abject darkness, drunk on soporific honey, he cries out sometimes–for he is troubled by dreams of horrors yet to come.