Thursday, August 31, 2017

Student Loans Exceed Credit Card Debt

kw: book reviews, nonfiction, lending, student loans, debt

A good friend of mine was "killing himself by degrees" prior to age 30: he has four degrees, the familiar BS - MS - PhD in science, and a MS in Computer Science. He married a woman with two degrees in Fine Arts (and she is indeed a fine artist). They entered upon a new marriage and new careers with loads of student debt. However, he landed a job at the company I worked for, in a well-paying position, so in addition to making payments on their student loans, after a couple of years they were able to buy a house. It took them until their mid-forties to pay off all their student loans. I count them lucky.

Equally lucky are those who at least partly "work their way through". They finish a BS or BA degree holding debt that is no more than half a year's pay at a reasonably good job, say, $25,000 or less (The median wage in 2015 was $56,500). Over ten years at low interest, the payment would be about $220 monthly. That's only about twice what many folks pay for cable TV.

A growing number would not consider themselves lucky in any way. They borrowed $30,000 to $80,000 to fund an education that prepared them for years of unemployment or a "desperation job" (a McJob) that doesn't pay them enough to rent a tiny apartment with three roomies that is "only" a 10-minute walk from a bus stop. Car? You gotta be kidding! They live in their parents' house and borrow their car.

Let's face it. The job market for English and History and Anthropology majors, not to mention majors in Women's Studies, Social Science, Art, and almost any other "liberal art" is next-to-invisible. A few hundred college professors in "humanities" departments, at most, retire yearly. Not all are replaced (the student body is shrinking). If you have a degree in History, nearly the only jobs in History are that tiny pool of college professorships, for which you need to get a PhD anyway, at even greater expense. Or you can get a MS in Education and try for a teaching job at a high school or middle school. That job market is pretty small also, and shrinking.

OK. So you're lucky. You got a degree in a STEM discipline: Geology, Physics, Engineering, Math, even Industrial Engineering. You're marketable. Whew! The book probably isn't for you anyway.

Let's take a side tack for a moment. I am about to have a pair of roofers fix some squirrel damage to our church's roof. They'll probably work most of a day. The estimator's bid is $875. Considering that some of that money goes to the company and some to the boss, still, each worker will get around $250-$300 for the day's work. That comes to $60,000 to $72,000 for a year, as long as their company can keep them fully employed. And you know what? Nobody in India or China or Mexico or Vietnam can take that job. You can't "outsource" roofing! Nor plumbing, painting, carpentry, electrical work, landscaping, paving, and a host of other "trades". None of them require a college degree. Most of them pay better than teaching school, which these days requires two degrees (the low pay for most teachers is an injustice I'll take up on some other occasion).

For me, the hero of America's prosperity is not the college professor in the ivory tower, but the people interviewed by Mike Rowe for the Dirty Jobs series on the Discovery Channel. Mike is an actor, but the people doing the work sure aren't. To me they are heroes. And it would be a good idea if people had to work at a tough trade for several years before they were admitted to college!

This is all a riff on recently finishing the book Game of Loans: The Rhetoric and Reality of Student Debt by Beth Akers and Mattew M. Chingos. I don't really have much to say about the book itself. It saddened me, but not for the usual reason. I know enough already to be sad about abusive student debt, which is why we struggled to get our son through college debt-free. No, I am saddened by the lengths to which the authors go to minimize the reality, and they all-too-frequently "blame the victim".

I am a political conservative, though that term is losing its meaning these days. But I am also a social liberal, in the old sense of making people free, of giving them a hand up but not a handout. "Handout" politics is actually socialism, and there are darn few non-Socialists in today's Democratic party. I am not sure I would count Toni Morrison as a socialist. She is definitely a social liberal, and when I heard her speak at the commencement for our son's BA degree, she said this (not an exact quote; it has been a few years), "Will the day come that people will look back on our generation with astonishment that we required the best among us to pay for their own educations?" I agree with this, in part. Our system needs to re-gear itself toward having every student exit the "halls of academia" debt free. But I think it is healthy for a student to have some skin in the game. That means doing some work to pay for part of their education.

It is unhealthy for someone to finish college with a degree or three or four, having never worked at a job people were willing to pay them to do. It is unhealthy for massively unprepared 17-year-olds to be dropped into a super high-school environment with no parental oversight, and with no understanding of the source of the funds hidden behind the meal card they swipe at the all-you-can-eat buffet many colleges now have in place of the "food service" I "enjoyed" at Kent State in the 1960's. (P.S., There was no "freshman 15" then. Most Frosh lost weight their first year of college.) It is unhealthy for students to find themselves faced with 20 or 100 options for "student aid", most of which involve debt under terms they haven't been educated to read with any understanding, and confusing qualifications that waste their time when they apply for things they can't get anyway.

I say "unhealthy". Debt-ridden college graduates are sick. Job-unprepared graduates are sick. We need a culture shift and I am not sure how to even describe it.

The authors of Game of Loans decry the difficulty of finding information about the cost-benefit ratio of most college degrees. This is true: Congress has passed laws specifically forbidding the gathering of such information! Guess which lobbyists supported those laws? But we don't really need information in such detail. Just look at the job market. Go to any employment agency and ask for a breakdown by job type.

Oh, I forgot for a moment: If you have read this far you are not likely to be a Millennial, but if you are, you never "go to" any such place as an employment agency. You want everything online. OK, go to the Bureau of Labor Statistics website, the Occupational Outlook Handbook (OOH) ( Dig around and find out whether there is much future for the kind of job you "sorta want" (I know, Millennials are practically free of passions). Here are a couple of examples I found by digging around:
Fine Arts or Crafts. About 50,000 jobs held in 2014. Growth rate less than 2% (or about 1,000 new jobs per year). Half of the jobs are "self employed". Median pay is under $49,000/year. Digging elsewhere we find that about 100,000 new BA's in Fine Arts graduate yearly. Only 1% will be able to make it pay, and half of them will spend more of their time running the business than "making art".
Environmental Scientist. About 95,000 jobs held in 2014. Growth rate 11% (~10,000 new jobs yearly). Median pay $69,000/year. I didn't find stats on graduation rates. But there are about 20 times as many jobs available as there are for artists.
Carpenter. Just under 1,000,000 jobs in 2014. Growth rate 6%, or about 60,000 new openings yearly. No college is needed but it usually takes 3-7 years in an apprenticeship program to become a Journeyman and earn pay in the mid-$40's or more.
I picked the first item because I have a young friend who is quite a good artist and illustrator. He wants to work in animation, even Animé. That's a smaller field than fine arts in general. There is little hope that he will ever be anything beyond "self employed" (struggling/starving artist working nights at a McJob to pay rent and buy beans to eat).

The biggest and most important educational innovation that could be performed for America would be to teach our young people the meaning of "employable": You must be able to do something people are willing to pay for. Period. If you need college credentials to get such a job, dig around in the OOH web site above for a dose of reality. Is it worth $30,000 in student loans to get a ½% chance of paid employment as an artist? Or is that four or more years (5-6 is common now) better spent in an apprenticeship program for carpentry, or electrician (2/3 the jobs as carpenters but better pay)? Get a part time job teaching art and making art at a private school of the arts (like I did with music).

I am in favor of programs advocating trades. I read that three million jobs in the trades are just waiting for competent workers to fill them. People go to college for many reasons, but I suspect for many of them, it is that they don't want to sweat on the job. The Bible has two things to say about that:
By the sweat of your brow you will eat your food until you return to the ground, since from it you were taken; for dust you are and to dust you will return. — Genesis 3:19
For even when we were with you, we gave you this rule: “The one who is unwilling to work shall not eat.” — 2 Thess. 3:10
These two passages are the basis of social conservatism. But they also highlight a problem with the education-versus-work culture in America today. Our youngsters are told (as my generation also was told) that they need a college education to get a "good job." But what is a "good job?" One that doesn't involve bodily sweat? When a plumber's hourly pay is greater than that of the accounting clerk going blind at a "desk job", which one has the better job?

Colleges charge 'way too much because their "services" are in demand. That demand is part of the problem. I have been sorry to see the demise of most of the nation's Vo-Tech and Trade Tech institutions, while we churn out tens of millions of unemployable college graduates who think they "deserve" a better job than driving a backhoe. Backhoe operator is a pretty skilled occupation! It frequently requires problem solving skills that would surprise you.

Parents of students entering high school, and high school students: Think about what you really want to do. Find out how likely it is that someone will pay good money for that to be done. The fastest growing occupations for the next decade or so will be in personal care and health care for all of us aging Boomers! Think about that. Construction trades are big right now but they may enter a period of decline, because Millennials, today's twenties and thirties, aren't so much into buying McMansions, compared to Generation X. And do yourself a favor. Unless you have both the love and the talent for a top profession such as medicine (which Obamacare is destroying), take off a year or three from education and work in a trade before deciding on a college major, if any. Examples from my experience:

I am one of four brothers, and our life arc has been thus:

  1. Me, the eldest. Majored in Chemistry, switched to Physics, finished in Geology after 7 years. Two of those years were working full time to pay my way through the rest of college, and part time work during the rest of college. Then I worked as a Draftsman who also did computer coding. Returned to graduate school at 32, getting a MS at 38 (another 7 years), working my way through with teaching and consulting. Worked as a coder until retirement at age 66, and was never paid a nickel to do any geology. I work part time in retirement, more by choice, but the added income is nice.
  2. Majored in Physics and Art History, graduating in 4 years. Worked his way through school as an electrician's apprentice. A calligrapher and carver, worked as a "starving artist" for 20+ years, making ends meet as an occasional coder. Returned to school and got a MA in History and PhD in Archaeology by age 50, working his way through as a book illustrator. Now a college professor. Age 66, with no end in sight.
  3. Majored in Mechanical Engineering. Worked in Environmental Equipment design until company folded when he was 60. Now works as a Maintenance Tech.
  4. Didn't finish college. Tried various "management training" type jobs with friends, but best pay has always been handyman and home remodeler. He is good at it. Age 62, with plenty of work and quite good pay.

None of us had college loans. We would have floundered had we had such debt to pay off.

You may wonder why I didn't really review the book. That is because it misses the point so badly.

Tuesday, August 22, 2017

Hi, Russian spiders. I'm still watching!

kw: blogging, blogs, spider scanning

The various tools on the Stats page in Blogger just showed me that these 181 hits from Russia all occurred in the 5:00 AM hour. I presume that is Pacific Daylight Time. That would be about 3:00 PM in Moscow and 7:00 PM in Novosibirsk, a more likely source.

If I decide to pay for the more precise analytics I could pinpoint the city, but I'll leave that to others. Considering that this blog has quite low popularity, I wonder whether the same spiders are making a big impact on really popular sites like the Freakonomics guys. Is anyone else out there even checking their stats?

Sunday, August 20, 2017

Your English isn't your grandfather's English

kw: book reviews, nonfiction, language, words, linguistics, historical linguistics

I find John McWhorter fascinating: he digs out so many lovely examples of language usage, and writes about them so engagingly… In a prior book I reviewed in 2009 (Our Magnificent Bastard Tongue) he brought to our gaze the numerous chunks of other languages that were dragged together almost wholesale to produce what we today call "English". Now in Words on the Move; Why English Won't—and Can't—Sit Still (Like, Literally), he provides an antidote to the amount of energy some of us "seasoned citizens" give to decrying the trends of change in language usage (Like, you know, gag me with a spoon if I have to keep hearing that!).

That last string of phrases caused much angst in my generation when "Valley Girl" (Val Gal) talk sprawled across the nation like a lanky teen on a love seat. In particular, "like" has gone from a word meaning (as a verb) "to desire or feel affinity to" or (adjective, adverb, etc.) "similarity", into a "piece of grammar", no longer really a word, but a functional sound that has morphed from the "similarity" end of things to at least three or four uses, most particularly a kind of bullet point, such as an example on page 215:
"So we're standing there and there were like grandparents and like grandkids and aunts and uncles…"
"Like" has become more a signal than a word, and this isn't new, it started almost a century ago, some 30 years before the Beatniks began to say, "Like, wow, man!". The new "like" has gathered new uses to the extent that McWhorter touches on it in three different chapters and spends a dozen pages on it in his last chapter, "This is your brain on writing." This word is an example of several he discusses, that are grammatical markers and have become very hard to explain as words. They are "grammaticalized." Consider what "well" or "so" might mean when used to begin a sentence. Could you explain them to an inquisitive five-year-old? Thought not!

Gliding back to the first chapter, "The FACEs of English", we find a long discussion of the acronym FACE, used to describe the uses of grammaticalized words such as "well" or "so", which a linguist would call "Modal Pragmatic Markers" or MPM's. Here "pragmatic" most closely means "personal". Our author states that a multitude of such words are needed so that we don't just speak English, we can talk.

This brings us to a major theme of the book, the difference between written and spoken (or "talked") English. Firstly, of course, we use fewer grammaticalizations when writing. I tend to write at full speed as though I were having a conversation with you, so I almost began this paragraph with, "Now, …". Were you and I really talking together, that's how I would have said it. But even writing full speed at 50wpm or so, I edit as I go and make the written form a little more compact, and, I hope, readable. (Those who find me long-winded are saying, "Oh, really!")

He dwells much more on spelling. For example, written English has a pronunciation rule of "silent, terminal e", that it makes the vowel before the prior consonant into a long vowel. Thus we have "mad", meaning crazy or angry, in which the "a" is pronounced as flatly as possible and is often called "short A"; and we have "made", meaning constructed or produced, in which the "a" is pronounced almost like "eh-ee" and is called "long A". The author tells us that nobody would design such a system from scratch, and that it had to arise from some process. Indeed it did. He discusses the "Great Vowel Shift" on pages 152-159, using a map of the placement of vowels in our mouth to show how the "short A" of 5 to 9 centuries ago morphed into a longer "E" sound then to the "long A", and that a final "eh" sound at the end of many words was gradually dropped. Thus, "made" was once pronounced "mah-deh", as the spelling suggests, shifted through "meh-də' ", which a much shorter final syllable, shown by the schwa (ə), which is more of a tiny grunt than a vowel, and then into the one-syllable word of today. The Great Vowel shift moved all the vowels about, leading certain words that once rhymed to have different sounds now than then, and they no longer rhyme. "Water" and "after", in "Jack and Jill", used to rhyme perfectly. No longer.

Dictionaries began to be written for English very early in the Great Vowel Shift. While this didn't exactly entomb all the spellings in stone, they did tend to hold things back, and today, dictionaries of "modern English" have to trot to keep up, having been rendered out of date by our movable language just in the time needed to research, typeset, and publish them. By the way, usage of the words "typeset" and "typesetting" is dropping, having peaked in the 1980's; they are being overtaken by "key in" and "keying in". As computers get better at speech recognition, those will drop off also.

Here is side point that I enjoyed. Do you ever hear the expression "willy-nilly"? I figured out long ago that it came from "will I, or nill I", but I wasn't sure just what "nill" meant. Dr. McWhorter has the answer. A millennium or so ago, negating words was done by adding the prefix "ne-", so to "not will", or not desire, something was to "ne-will" it. To say you don't have something, you would say, "I ne-have it", but by Chaucer's time it would have been "I nave it", with "nave" pronounced "nah-veh" or even "nah-və". And Chaucer spelled it næbbe. It seems the consonants have shifted as well, but the author has left that for a future book, I reckon.

I'll forbear further nerdifying. It is a delightful book, and an incredibly informative one. I am thinking of giving a copy to a friend who is a linguist, but primarily of Chinese, not English, to see what similar trends might have occurred in Mandarin, which the Chinese acknowledge is not a written language at all: the "written Chinese" language is one that nobody speaks, but they all know how to interpret it into whatever dialect they grew up speaking.

Thursday, August 10, 2017

Amidst the hype, an Eclipse book of value

kw: book reviews, nonfiction, science, history, eclipses

OK, let's get the ooh-and-aah stuff out of the way first. This image shows the eclipsed Sun in an intermediate state: a medium amount of corona and several prominences are visible. The solar prominences are the red bits around the rim of the Moon. The image was enhanced by unsharp masking to show more of the corona, which has a sharp drop-off of intensity with distance from the solar photosphere (the "surface").

Viewing an eclipse without magnification, you are unlikely to see the prominences, so it helps to have a telescope set up ahead of time, its clock drive running, ready for action the instant that second contact occurs. A magnification of 30-to-60x is sufficient. This is about how the Sun would look at 30x.

Perhaps you know that the Sun has an 11-year cycle of activity. During periods of low activity, it is more likely to look like this (and this photo was enhanced also). This is an older, black-and-white photo, but I suspect few prominences would have been visible in a color image.

Interestingly, even in quiet years the corona may be quite extended, though it tends to be smoother. 2009 was a very quite year, according to records at, the Sun's face was free of sunspots on 260 days, 71% of the year.

At the peak of a sunspot cycle, sunspots are typically visible every single day, or very nearly. Sunspots are evidence of the "wound-up" condition of the magnetic fields inside the Sun. Prominences and flares are triggered by magnetic re-combination events.

A large, active corona is seen here. Looking carefully (click on the image for a larger version), you can see prominences. The rather bright blob at right might be a coronal mass ejection. When one of these occurs in the center of the Sun's face, we can expect a magnetic storm on Earth in 2-3 days' time.

To see what the outer corona looks like any time, look at the LASCO images at the Solar and Heliospheric Observatory (SOHO) satellite's image and video gallery here. One cannot see the close-in corona because the satellite's coronagraph is about two solar diameters across. Sometimes I've looked at a video of the past week or so and been able to watch a comet "auger in".

Now, to the book. John Dvorak is an exceptionally good writer, with much of value to say, and in a time of extraordinary hype about the solar eclipse that will occur across the entire U.S. in just 11 days, he has produced a valuable book of lore, history, and scientific explanations: Mask of the Sun: The Science, History, and Forgotten Lore of Eclipses.

While most people through history have viewed eclipses of both Sun and Moon as dramatic omens of misfortune, there have always been a few wiser folk who realized that though they are so infrequent, they are subject to natural laws. While a total solar eclipse is visible over a small area, a swath no more than 112 km across, partial eclipses can be seen as far as about the diameter of the Moon (3,473 km) on either side of the central path…or a bit farther because of the curvature of the Earth's surface. Thus, if there is a solar eclipse going on, the majority or people on the sunlit side of Earth at the time will be able to witness at least a partial eclipse.

Since the sky doesn't darken much during a partial solar eclipse, how were they noticed in antiquity? Think pinholes. The crescents seen here were in shadows cast by leaves of a tree. If you are used to seeing the round dots on the ground or a wall in a tree's shadow, then you'll likely be drawn to the view when they change shape. Pinhole viewing of partial solar eclipses has been recorded over at least the past 2,400 years.

So, although an average location on Earth experiences one total solar eclipse about every 330 years, a partial eclipse is likely to be seen about every 2-3 years from almost anywhere. With a bit greater frequency, almost anywhere you live you'll be able to see an eclipse of the Moon almost every year, because they are visible from an entire hemisphere at once.

In classical times, one of the seven required subjects of  a classical education was Astronomy, which actually meant learning to gather naked-eye observations and make the calculations to determine the motion of the Moon and the naked-eye visible planets (Mercury, Venus, Mars, Jupiter and Saturn), primarily for astrological purposes and to (very roughly) predict eclipses. Much of Mask of the Sun discusses the ebb and flow of lore and superstition about eclipses, both lunar and solar. Kings and emperors employed skilled mathematicians to predict eclipses, because unfriendly (or hype-engrossed) persons were making the same predictions, and then predicting the likely demise of whomever was in power at the time. A leader with better advance knowledge could then take advantage of public magical ceremonies intended to stave off the disaster and survive the eclipse, which really meant to stave of the likelihood of a revolt.

Eclipses earned great practical value during the "age of sail": they can be used to determine longitude. It isn't easy, but it was too valuable an aid to navigation to not perform. First, one must have a good (relatively speaking) time-measurement device. The water clocks and other mechanical timekeeping devices in use before the pendulum clock was invented in 1656 (by Huygens) were better than counting heartbeats, but not by much. You, the seafaring captain intent on determining the location of some distant port, would contract with an astronomer at home to determine the time at which certain critical events occurred,and their location in the sky, usually during a lunar eclipse. This requires a bit of explanation.

The shadow of a planet or satellite has two parts, the Umbra and the Penumbra. When you see a total solar eclipse, during the time of totality you are standing inside the Umbra. Before and after totality, and in any place where a partial eclipse is witnessed, that is in the Penumbra. There are thus four contacts that delimit a total solar eclipse:

  1. The Moon first impinges on the edge of the Sun.
  2. The Moon fully covers the whole Sun.
  3. The Sun first begins to exit from behind the Moon.
  4. The last bit of the Moon exits the edge of the Sun.

The same four contacts pertain to a total lunar eclipse, except they refer to the impingement of first the penumbra of Earth's shadow, then the umbra, shading the Moon, and then the Moon's exit from first the umbra and then the penumbra.

By taking readings with a sextant or octant of the Moon's position in the sky when each contact occurs, and noting the time of each as exactly as possible, both you and the astronomer back at home gather data that can be used to calculate the longitude difference between the place you were and your home port. Of course, latitude is much easier to measure in the Northern hemisphere by sighting the north star. Seeing the orientation of the Big Dipper lets you correct for the star's offset from the actual pole, which is presently about one degree (Because of Earth's precession, Thuban in the constellation Draco was the star nearest the pole 5,000 years ago, when the pyramids were a-building in Egypt). Prior to the late 1700's, when very accurate marine chronometers were invented, it took months to learn "where" you had been! And then you might still be off by a few degrees (each degree is 60 nautical miles, that is 69 mi or 111 km).

During a total solar eclipse stars become visible. In 1919, this photo was taken and the two stars marked with little dashes were among those used to verify Einstein's general theory of relativity.

Spectroscopy of the solar corona was first done in the 1860's, and led to a paradox that has not yet been resolved. The spectroscope had revealed that the Sun's photosphere is at a temperature of about 5800K (about 10,000°F), and later that the middle part of the chromosphere, a thin pinkish layer just above it, is at about 3800K (about 6,400°F). But the corona had a puzzling spectrum that wasn't figured out until the 1930's and 1940's: its temperature ranges from one to three million kelvins! That's two to more than five million °F.

Before I close I must mention the two central solar eclipses I have seen. The first was July 20, 1963, when I was not quite 16. The Moon's shadow crossed from northwestern Canada to Maine. My family took a vacation starting nearly two weeks earlier, to Montreal and Quebec, and then on the 20th we crossed into Maine at a spot where the highway would be right at the center of the umbra. I had fitted a telescope with a projection screen, with which we watched from just prior to first contact until second contact. Then we looked at the sky to see the Sun and its corona. The hillside had a view to the northwest, and we saw the umbra racing toward us just before second contact. Seeing something, even a shadow, approach at 2,000 mph is amazing! Seeing the "hole in the sky" surrounded by a large corona was amazing! In just over a minute, it ended and third contact occurred. We saw the "diamond ring", the first bright ray of sunlight peeking through a mountain pass on the Moon.

The second was the annular eclipse that passed through Ponca City, Oklahoma, May 10, 1994, when I worked for Conoco. This picture shows the projection screen attached to my telescope, and the eyepiece is visible at the right edge. This is the same telescope I used in 1963, and I still use it. Annular eclipses occur when the Moon is in a further part of its orbit, near apogee, and doesn't cover the entire Sun.

Conoco management gave everyone half the day off. School groups and others were invited on-site. A filtered video camera was used to broadcast the eclipse inside the buildings on TV monitors usually used for executive communications. At least twelve telescopes were brought onsite by Conocoans and a few others, and used, usually by projection, to show the Sun to groups of people. One friend of mine brought a large telescope fitted with a full-aperture solar filter, so you could look through his wide-angle eyepiece at a 100x view of the whole Sun. Now, that was an amazing view!

While the publication of Mask of the Sun was timed to take advantage of public interest in the solar eclipse that will be seen all across North America on August 21, 2017, it is not hyping the eclipse, but instead giving us a primer into the past and continuing importance of eclipses. For example, eclipses on earth and elsewhere (notably, shadows of Jupiter's moons on that planet's cloud tops) are still one of the key ingredients to measuring planetary distances in the solar system. I have deliberately touched on only a few of the many delightful matters covered in the book. It is well worth reading by anyone with any level of scientific education.

Saturday, August 05, 2017

To survive, dig in

kw: book reviews, nonfiction, science, paleontology, zoology, burrowing, mass extinctions

Shortly after we moved to our house 22 years ago we bought some flat stepping stones for high-traffic areas in our yard, such as the path through a "gate" in a hedge. I dug these in to be an inch or so above ground level, a little lower than the mower blade at its lowest setting. Now, nearly all of them have sunk to ground level or below. Two examples are shown here. Is this just soil compaction from the stones being walked on? Not entirely. Wherever I dig in my yard, I encounter several earthworms in every shovelful.

Charles Darwin spent about 20 years studying earthworms, and using "worm stones" plus an ingenious measuring device attached to bedrock beneath, determined that bioturbation (the modern term) of the subsoil by earthworms caused the stones to sink by an average of 2.2 mm/year. Darwin's earthworms must have been very energetic. The "sink rate" for my stepping stones is closer to 1.0-1.5 mm/year.

One of Darwin's worm stones is pictured in The Evolution Underground: Burrows, Bunkers, and the Marvelous Subterranean World Beneath Our Feet by Anthony J. Martin. Dr. Martin's thesis is simple: burrowing and other means of living below ground at least part of the time is so beneficial that many animals are burrowers. I don't know if you could say "most animals", but that might be true (he doesn't say). Also, burrowers provide homes for other species that share their spaces. The author makes a good case, with numerous examples, that living at least part time underground enabled many animal species to survive the various nastinesses we call "mass extinctions".

The "big five" mass extinctions had such profound effects on both biology and geology that they mark geological boundaries (the abbreviation "mya" means "million years ago"):

  • Ordovician-Silurian boundary, 429 mya. About half of species vanished, and about 85% of all animals died.
  • Late Devonian, 364 mya. About 75% of species became extinct.
  • Permian-Triassic boundary, 251 mya. The baddest of the bad, this one drove 96% of species extinct. All living things today are descended from the remaining 4%.
  • Triassic-Jurassic series, between 214 and 199 mya. By the end of this 15-million-year period, more than half of species had been eliminated.
  • End-Cretaceous, 65 mya. This is the best known, because it centers on an asteroid impact and led to the demise of the dinosaurs…or, at least, the non-avian dinosaurs. It is now known that birds are dinosaurs, or, if you prefer, birds are descended from theropod dinosaurs. 76% of species went extinct.

Many cases show that animals that were underground during the big smash, or whatever happened, were the most likely to survive in numbers sufficient to restore their populations afterward and become the ancestors of modern life. But before the first of the mass extinctions, there were big changes as animal life arose and developed, including the development of the first burrowing creatures. An odd group of animal species called the Ediacara Fauna did just a little burrowing, but were followed by the "Small Shelly Fauna" that burrowed more and deeper, and then the proliferation of hard shells that marks the beginning of the Cambrian period also marks the beginning of rather thorough bioturbation of ocean floor sediments.

The author shows the history of animal life from the perspective of an Ichnologist, a scientist who studies trace fossils. This picture, a 6"x8" section of a rock about 15" square, shows trace fossils on a rock I picked up from a sandstone bed near the base of the Morrison Formation in South Dakota, so it is about 150 million years old. This is a bottom cast; we are "looking up" at sediment that settled into tracks and shallow burrows in the late Jurassic sea bed.

Somewhat visible are ripples crossing from top right towards bottom left, showing that this was in rather shallow water. At least three kinds of tracks are visible, though I don't know what animal made any of them. Other dug-in structures are seen, or rather, their casts. Dr. Martin and his colleagues are experts in discerning the meaning of such traces.

Before digging into his subject, however, the author discusses "A brief history of humans underground." If you've heard of Cappadocia, you may know of the underground homes dug into the soft sandstone. That has been going on for several thousand years! Long before that, humans utilized natural caves, not only for shelter and burials but even for their art (think of the amazing art in the caves at Altamira and Lascaux).

While we tend to denigrate "cave men", thinking only Neanderthals lived in caves, the "art gallery" caves were painted by our species. When there were only a few humans worldwide, it makes sense to consider that many or most of them used caves and sometimes stayed in them for extended periods, not just during bad weather or extreme seasons. A cave is easier to defend from predators. And just as the burrows of gopher tortoises permit them to thrive in areas with tough winters, so caves shield those who dwell in them from climatic extremes. Indian Echo Caverns, in Pennsylvania about two hours from where I live, was the home of William Wilson from 1802-1821. The "Pennsylvania Hermit" stayed pretty well wrapped up most of the time, because the cave stays a nice, chilly 54°F (12°C) all the time.

There just aren't enough caves to go around, so now we build artificial caves we call "houses". One of the professors at South Dakota Tech had an "underground house" when I was there in the 1980's. It was technically a house built into a tight place between two rock outcrops. An underground house is nearly free to heat or cool, if it is in the "temperate band" across the world where average temperatures are between about 60°F and 75°F (16°C-24°C). The below-ground temperature near Rapid City, SD is closer to 47°F (8°C), so my professor had to insulate the excavation, pour concrete for the dwelling, and insulate more. South of Oklahoma in the U.S.A. an underground house would not need heating or cooling (just moisture control, perhaps!); in Europe, think Spain, Italy, Greece and Turkey, including Cappadocia.

This may become more pertinent in another generation, if the climate continues to warm. I will be even more pertinent when the "Holocene warming" that began about 12,000 years ago comes to an end and another 100,000-year Ice Age begins! Today's "global warming" caused by "carbon pollution" (an oxymoron; we are made of carbon and its oxy- and hydro-derivatives!) may actually delay an ice age by a century or so.

The most ubiquitous burrowers and tunnelers, humans aside, are invertebrates. Earthworms don't leave open tunnels; their burrows fill in behind them with the excreted feces from which they've digested key organic materials. But ants and termites produce long-lasting tunnels. Some of these have been studied by pouring in plaster or even molten aluminum. This cast of an ant nest is from leaf-cutter ants of Central America.

There is a surprising array of vertebrate burrowers, however. We are familiar with gophers and voles, perhaps, but certain birds burrow, such as kiwis, bee-eaters, and some penguins. The gopher tortoise, as its name suggests, is quite a digger, and its burrows shelter at least 400 species that are enabled to live in otherwise inhospitable places because of a tortoise's "hospitality".

The author also discusses the most amazing tunneler of all prehistory, the giant ground sloth. You might not think of an animal the size of a 4-door sedan as a burrower, but in southernmost Brazil there are hundreds, perhaps thousands, of burrows you could literally drive a truck through! The tunnels are 4-4.5 m wide (13-15 ft) and 2-2.5 m high (6.5-8 ft).

The last Brazilian ground sloths died (probably eaten by early Brazilians) about 12,000 years ago. They had used their strong claws to dig though soft, semi-cemented sandstone. The various species of giant sloth lived through numerous ice ages, having evolved about 23 million years ago, or perhaps earlier. Great bulk is itself helpful for surviving great cold, but burrowing confers an added advantage.

Biologists and paleontologists in general pay most of their attention to animals that lived above ground. True, finding and recognizing the fossil of an animal that died underground is more difficult. But there is so much going on beneath our feet, and so much of prehistory that took place underground, that we must realize that the livability of our environment is largely a result of these hidden lives. Scientists of all stripes would do well to take note.

Are we the cause of a great extinction being called, by some, the Anthropocene? If we are, it is mainly affecting the critters above ground. If we should extinct ourselves at some point, the "rulers of the underworld" will remain, and may hardly notice much difference. They will continue their ecosystem services as before, keeping a significant percentage of the subsurface a nice place to make a home.