Wednesday, June 6, 2018

What is a horsetail fall?

Horsetail Falls in the Sierra Nevada (June 3, 2018)

A horsetail fall is a waterfall, the water of which maintaining contact with the bedrock in most places of the water trail. The descriptive word “horsetail” is a geometric classification; other types of waterfalls are “plunge,” “fan,”  “block,”  “chute,”  “scree,”  “ribbon,” and “punchbowl,” for example [1]. The list goes on. Standing in front of your favorite waterfall, you certainly will come up with your own term for a geometric waterfall description.

The water of a horsetail fall descends along a sloped surface followed by a steeper slope or edge where the water—depending on its speed—may shortly loose contact with the surface of the underlying hard rock. If you (without slipping or sliding on wet slopes) are able to get a side view of the water course of a horsetail fall, you may with a trigger of fantasy see a white water silhouette above the bedrock that resembles the shape of a horse's tail dangling down the butt. Terminology in anatomy meets waterfall classification terminology.

Often, a waterfall consists of a series of such horsetails, as is the case with Horsetail Falls (note the plural).  This waterfall is located southwest of Lake Tahoe in California [2]. It is fed by lakes such as Lake of Woods in  the Desolation Wilderness in hiking distance from the popular Echo Lakes. The bottom of the Horsetail Falls are best accessed via the Pyramid Creek Loop Trail, about 1.25 miles upslope from the Pyramid Creek Trailhead next to Highway 50.

Horsetail split within the Horsetail Falls structure

Keywords: geography, terminology, waterfall names.

Reference and more to explore

[1] Waterfalls 101: What Types Of Waterfalls Are There? World of Waterfalls. Link:

[2] Horsetail Falls, Eldorado County, California, United States. World Waterfall Database. Link:

Friday, May 25, 2018

What is the name of our sun's “mother” star?

Many of us grew up learning that a star comes and goes—ending its “life” by supernovae explosion or as a red giant turning into a white dwarf, for example. But the life story of a star has neither a sharply defined beginning nor a total ending. The death of a star can give birth to new stars by providing gas, dust and debris to built up new objects in space: solar system genealogy continues by recycling matter.

Recent research, including observations and modeling, suggests that the solar system had a parent star, which after its burst seeded the space with enough atoms of various chemical elements to make possible the formation of our solar system, and maybe even “sibling”systems [1-5]. The astrophysicists Matthieu Gounelle and Georges Meynet proposed to call the sun's “mother” star Coatlicue, after the Aztec mother of the sun [3-5].

Coatlicue (pronounced Co-at-li-cu-e) is the Aztec earth-mother goddess and patron of childbirth [6]. She also is seen as the goddess who gave birth to the moon and stars including the sun. She essentially was the “mother of everything” in Aztec mythology [7]. And from a planet Earth viewpoint, Coatlicue definitely was—unless new findings will make it necessary to redraw the galaxial family tree of star evolution within our corner of the Milky Way. What if there were multiple mothers and the picture of a star family tree needs to be replaced by a more elaborately networked star-descendency graph?

Keywords: Coatlicue; cosmochemistry; solar system formation; mythology.

References and more to explore

[1] S. Pfalzner et al.: The formation of the solar system. Physica Scripta April 2015, 90 (6). Link:
[2] R. Boyle: The Secret Life of the sun. Scientific American, June 2018, 318 (6), 26-33.
[3] M. Gounelle and G. Meynet: The solar system genealogy revealed by meteorites. Astronomy & Astrophysics August 2012, 545, article number A4. DOI: 10.1051/0004-6361/201219031.
[4] CNRS: Solar system genealogy revealed by meteorites. August 2012. PHYS.ORG. Link:
[5] A. Morlok: Die Galaxis ist gerade mal groß genug für uns. December 2015, EXO-PLANETAR BLOG. Link:
[6] M. Cartwright: Coatlicue. Ancient History Encyclopedia, November 2013. Link:
[7] Coatlicue mother of the Sun. astronoo, 2013. Link:

Friday, March 30, 2018

When to drop the “ad” and “ab” prefixes

The prefixes ad and ab are generally used with the meaning toward and away from, respectively. But not within every context is the meaning and distinction that clear. An interesting example comes with the terms adsorption and absorption—near homophones. The noun adsorption refers to the attraction of something toward the interface of an object, while absorption means that something has been drawn into the bulk of the object through the interface. But where does the interface end and where does the bulk begin? And what if the subject of interest is found both at the interface and inside the object?

Adsorption and absorption phenomena are studied in physical chemistry. They play a key role in many chemical engineering processes. Chemical species such as neutral molecules and ions may stick to a material surfaces and/or diffuse deeper into the substrate material. Robert Kunin, who worked in the field of ion exchange, thoughtfully elaborated on the “ad-versus-ab controversy” in the 1950s:  
If we consider adsorption processes strictly as confined to changes occurring at an interface or surface and absorption as those processes involving solids engulfing substances throughout their entire structure, then ion exchange phenomena may fall into both categories and might therefore be more safely considered as a sorption process, a term that avoids the controversy between the devotees of the ad and ab prefixes. --- [Robert Kunin, 1958].

Kunin elected to use the term adsorption within his book on ion-exchange resins, considering that “energy considerations of ion exchange are more closely related to true adsorptive processes.”

Often, your particular context will clarify whether to speak of  ad- or absorption. When in doubt or with excusable lack of commitment to detail, the unprefixed word sorption—as implied by Kunin—should be the word of choice. The expression “ad/ab-sorption” is possible, but may confuse more than help.

Keywords: terminology, prefix use, physicochemical vocabulary.



Robert Kunin: Ion Exchange Resins. John Wiley & Sons, Inc., New York, 1958 (Second Edition); page 5.

Saturday, March 10, 2018

What is the wood-wide web?

The expression wood-wide web is a play on the term world-wide web. Both terms refer to communication networks. But in the case of the wood-wide web, communication is non-digital: it is chemical. Trees and other plants are able to send signals and communicate via airborne substances including hormones. In addition to wireless communication, forest trees share information and resources through wired underground root systems in cooperation with networks of mycorrhizal fungi.

Richard Grant recently wrote about the complex life of trees in a Smithsonian article [1].  He met with Peter Wohlleben—a German logger-turned-forest-conservationist, who is known for his book The Hidden Life of Trees: What They Feel, How They Communicate. Therein, Wohlleben describes the wood-wide web in non-technical prose backed up with scientific research results and related literature. Grant recalls in his article how Wohlleben talked about trees forming alliances among themselves and with other species [1]:

“Some are calling it the ‘wood-wide web,’ ” says Wohlleben in German-accented English. “All the trees here, and in  every forest that is not too damaged, are connected to each other through underground fungal networks. Trees share water and nutrients through the networks, and also use them to communicate. They send distress signals about drought and disease, for example, or insect attacks, and other trees alter their behavior when they receive these messages.”

Other great writings that explain the world-wide web—plus examples of involved species—can be found in journals and blog posts [2-5].

What is the main difference between the wood-wide web and the world-wide web?
The latter is man-made, while, what is called the wood-wide web, is a complex biological system understood as a result of natural selection. World-wide webs—yes, we need to use the plural form since we don't talk about a global structure but locally confined worlds—may be around since the first time when trees and forests began struggling or thriving on earth's landscape.
Keywords: forest ecology, plant science, terminology, communication, signaling, networking.

Forest around Tahoe Meadows above Lake Tahoe: How connected is it?


References and more to explore

[1] Richard Grant: The Whispering of the Trees. Smithsonian, March 2018, 48 (10), pp. 48-57.
[2] Robert Macfarlane: The Secrets of the Wood Wide Web. The New Yorker, August 7, 2016. Link:
[3] Emily Stone: The Wood Wide Web. Featured by William Graham. Link:
[4] How Plants Work: The Wood-Wide-Web: Are Plants Inter-Connected by a Subterranean Fungal Network? Link:
[5] Z. T. Evans: Introduction ot the Wood-wide Web. Tellurian Studies, December 2, 2015. Link:

Saturday, December 9, 2017

What is a pre-Darwinian Darwinist?

The term “A pre-Darwinian Darwinist” refers to a researcher or scientist who foretook evolutionary ideas in his (or her) writings before Charles Darwin (1809-1882) published his book On the Origin of Species in 1859.

Who was a pre-Darwinian Darwinist?

Pre-Darwinism took place in the Darwin family itself. Erasmus Darwin (1731-1802), Charles' grandfather, foreshadowed  the theory of evolution in his scientific work Zoonomia, in which he discussed topics such as inheritance of acquired characteristics and also presented his thoughts on how one species could involve into another [1,2]. The Scottish journalist Robert Chambers (1802-1871) included ideas of evolution and transmutation of species in his work Vestiges of the Natural History of Creation (1884), anonymously published in 1844 [3,4]. Many other preeminent scientists and keen observers of the natural world in pre-Darwinian times advocated evolutionary— rather than creationist—explanations of species origin and biological diversity. Evolutionary theory was evolving.

Alexander von Humboldt as a word-barraging pre-Darwinian Darwinist

Alexander von Humboldt (1769-1859) was an explorer, naturalist and polymath. Darwin had Humboldt's Personal Narrative—the account of the Latin American expedition of Humboldt and Aimé Bonpland—next to his hammock on board of the Beagle (see page 257 in [5]). Humboldt and Darwin met in January 1842, while Humboldt accompanied his benefactor Friedrich Wilhelm IV of Prussia to England for the christening of the Prince of Wales. With the help of geologist Roderick Murchison, he managed to meet the then thirty-two-year-old Darwin. The gathering turned out to be a lecture with Humboldt talking endlessly and Darwin not having the chance of starting a meaningful discussion. In The Invention of Nature, Andrea Wulf writes [5]:

If the two men had talked properly that day, perhaps Humboldt would have discussed his ideas of a world governed not by balance and stability but by dynamic change—thoughts that he would soon introduce in the first volume of Cosmos. A species was a part of the whole, linked both to the past and future, Humboldt would write, more mutable than 'fixed'. In Cosmos he would also discuss the missing link and the 'intermediate steps' that could be found in the fossil records. He would write about 'cyclical change', transitions and constant renewal. In short, Humboldt's nature was in flux. All these ideas were precursors to Darwin's evolutionary theory. Humboldt was, as scientists later said, a 'pre-Darwinian Darwinist'.

Humboldt started the publication of his five volumes of Cosmos (Kosmos, in German) in 1845, fourteen years before Darwin published his Origin.

Keywords: biology, natural history, evolutionary theory, history of emerging ideas.

References and more to explore

[1] Erasmus Darwin: Zoonomia; or the Laws of Organic Life []; for example, see chapter XXIX. Of Generation.
[2] Erasmus Darwin (1731-1802) [].
[3]  John van Wyhe about Robert Chambers' Vestiges of the Natural History of Creation [].
[4] See footnote on page 288 in [5].
[5] Andrea Wulf: The Invention of Nature. First Vintage Books Edition, Vintage Books, New York, 2016

Sunday, October 8, 2017

Named for Georg Wilhelm Steller

Georg Wilhelm Steller (1709-1746) was an 18th-century German naturalist and explorer [1]. As a ship's doctor, he was accompanying Danish cartographer and Russian naval captain Vitus Jonassen Bering (1681-1741) on their expeditions to the north-eastern coast of Asia (eastern Siberia) and the western coast of  North America. Stellar became the first European naturalist who came ashore Alaska, where he described various animals of the North Pacific, some of which bear his name, either in the common or in the scientific name, or in both:
  • Gumboot chiton (Cryptochiton stelleri), the largest of the chitons
  • Steller's sea cow (Hydrodamalis gigas), a sirenian hunted to extinction
  • Steller's eider (Polysticta stelleri), a sea duck
  • Steller's sea eagle  (Haliaeetus pelagicus)
  • Steller's sea lion (Eumetopias jubatus)
  • Steller's jay (Cyanocitta stelleri)
The latter two “Steller animals” are also found in regions farther south, such as California. From a San Francisco Bay perspective, Nate Seltenrich writes about Steller's sea lion [2]:

We see mostly females and pups [along California's coast]. Males rarely appear except in the breeding season at rookeries, the southernmost of which is off the Oregon coast near Portland, says Cara Field, staff veterinarian at Sausalito's Marine Mammal Center. In 42 years the rescue center has seen only 35 Stellers, 11 of them already dead and the rest mainly young pups, Field says, kept company during rehabilitation by their tourist-thrilling cousins.

And about Steller's jay Seltenrich notes [2]:

The Steller's jay's range reaches south to Nicaragua. The largest jay in North America, it is identifiable as the only western jay with a crest. Although Steller's original specimen was lost (as was his sea cow skeleton, and presumably others) when the expedition was stranded for that fate winter [when shipwrecked on Bering Island], his field notes informed the naming of the Steller's jay in 1788. So next time his namesake crashes your backyard feeder, remember Georg Steller and the Russian expedition that pioneered Alaskan natural history. 

Also, plants have been named by and for Steller. Further, the Georg Wilhelm Steller Gymnasium in Bad Windsheim (Steller's place of birth) near Nuremberg, Germany, has been named to honor the explorer [3].

Keywords: natural history, zoology, discovery, Pacific coast

References and more to explore

[1] Auf den Spuren Wilhelm Stellers. 2009 StellerJahr Bad Windsheim. Link:
[2] Nate Seltenric: Steller: The Man Behind the Name. Bay Nature, October-December 2017, page 10.
[3] Willkommen am Georg-Wilhelm-Steller Gymnasium. Link:

Saturday, September 30, 2017

Fascinated by the word Kassel - and the city as well

Orangery near downtown Kassel
Kassel is a German city in northern Hesse. The geographic name “Kassel” derives from the Latin word “castellum”, which also is the source of the English word “castle”.

The history of Kassel begins with the ancient Castellum Cattorum, a castle of the Chatti [1]. The Chatti were an ancient Germanic tribe,  living in the upper Weser and Fulda river region since Roman times. In the tenth century the Franks took over the fortlet. They used the words “castella” and “cassela”. Before the current spelling “Kassel” was adopted in the late 1920s, the city name had been written in various letter combinations  including “Chassala”, “Chassela”, “Cassele” and “Cassel” [2].

Treppenstrasse in downtown Kassel

Antonia Baum recently shared her fascination with the word “Kassel” in a MERIAN essay [3]:

Kassel is a word where the K smashes into the double-S like a ladle slapping into a bowl of soup; or like careening down a hill wityh so much speed that the momentum takes you straight up to the other side. As a child, sitting in the backseat of our car while driving past Kassel on the autobahn, I always found it odd that this word existed and asked myself what on earth this Kassel was. What strange and wonderful things went on in Kassel that made it deserving of the name Kassel. I was fascinated by the word itself and would mumble “Kassel, Kassel, Kassel” to myself as I gazed out of the window.

Strange and wonderful things happen in Kassel every five years, when the documenta, the world's foremost art exhibition with avant-garde and often scandalous or grotesque displays and performances, is infiltrating the city's urban environment. Selected art objects from past documenta exhibitions keep staying in the city. Here are some snapshots of outdoor installations from documenta 14 in 2014 and from earlier exhibitions:  


Fulda river bank in Kassel with Claes Oldenborg's Pickaxe (Spitzhacke) 


[1] Kassel. Wikipedia:,_Germany.
[2]  Dieter Berger: Geographische Namen in Deutschland. Second Edition. Dudenverlag, Mannheim, 1999.
[3] Antonia Baum: The little lady in the black fur. Merian, English Edition, 2017