Freeman Dyson, RIP

Freeman Dyson died today, Friday, 28 February 2020, age 96, at a hospital in his longtime home of Princeton, NJ. A thoughtful obituary by George Johnson just appeared (Friday night, 28 Feb 2020) on the New York Times website.

Dyson was a mathematical physicist who knew the greats -- Feynman, Oppenheimer, Bethe, Teller, and the rest -- and became great himself by contributing the theory of quantum electrodynamics. He was one of the final living members of the World War II generation of scientists who invented cryptography, radar, and, of course, nuclear weapons and who later wrote about and lobbied vigorously for their safe and controlled use. These scientists saw themselves also as humans, citizens, and small-d democrats who knew the essential need for public discussion of issues raised by the technology they created.

Dyson reminds me of Jacob Bronowski. Both were Englishmen, both mathematicians, and both authors of books overlapping science and the humanities. Bronowski is best known for his public television series The Ascent of Man (1973). Dyson, likewise, wrote many popular books, though in an unpopular way. He dared to bring in Johann Wolfgang von Goethe, Bertold Brecht, Ingmar Bergman, T.S. Eliot, and other nonscientist people of culture.

One of those books, his 1979 memoir Disturbing the Universe, I read over a cross-country Greyhound bus trip in January 1983. What I discovered in it was not science, nor memoir, but humanity. Dyson, for example, compared Richard Feynman to Jof the Juggler in Ingmar Bergman's film, The Seventh Seal (1956). That film, central now to my understanding of life, I did yet know, but Dyson's book sent me out to see it when it finally caught up to me. Thank you, Professor Dyson. One does not expect to learn such things in a scientist's memoir! (Feynman, of course, I have long known. Like so many of my generation, I learned physics partly by perusing all three volumes of The Feynman Lectures on Physics.)

Dyson was technological optimist. Problems on earth -- be they overpopulation or climate change -- either were not as serious as claimed or could be overcome by even more technology, such as space colonies somewhere else in the universe. One would travel there by spaceships powered by nuclear explosions. It is here I lose touch with Dyson. Perhaps I lack his imagination. Certainly I lack his faith in technological solutions to problems of human nature.

Disturbing the Universe introduced me as well to Goethe's Faust, particularly this favorite line from its Part I. It is a fitting quotation to a remembrance of Freeman Dyson: "All theory is gray, / But the tree of life, my friend, is green."

posted 2020-02-28, edited 2020-02-29

How old is old?

What is the oldest thing found on earth?

Rocks, right? Some of the oldest rock formations are found in northern and eastern Canada and date back about four billion years. Immensely, unimaginably old they are, and yet the earth itself is older, dated to about 4.54 billion years. On earth, rocks are continuously recycled, broken down by weathering and erosion, and moved by water, wind, and gravity. And rocks are also built back up, reformed by sedimentation and remelting, pushed up again by our earth's ever-moving crust. Original rocks, present when our newly-created, molten planet had cooled and solidified, are likely long since recycled and remade by our dynamic living planet.

So how about meteorites, the rocky remains of "shooting star" reaching the earth's surface still intact? They are older still. At the local New Mexico Museum of Natural History and Science is found an iron-nickel meteorite collected from South America and dated to 4.55 billion years ago. "PLEASE TOUCH" says the sign by the meteor. Awed, I place my hand on its rusty metallic surface and try to feel the vastness of time that my rational mind cannot comprehend. "This may be the oldest rock you will ever touch" suggests the sign. Indeed.

Iron-nickel meteorite at the New Mexico Museum of Natural History and Science

Earth, sun, and the seven planets [1] of our solar system all originated together about 4.57 billion years ago. Originally part of rocky objects smaller than Earth but still part of the solar system, rocks that would become meteorites cooled faster and solidified sooner than Earth. Thereby they are older.

But can we go even farther back in time? Can we find even more ancient mineral-based substances on earth? Until recently I thought not. But now, I stand corrected.

Older matter ought to exist somewhere. Old as Earth and the solar system are, we are but recent arrivals. As the Big Bang creation is dated to about 13.7 billion years ago, some two-thirds of the universe's history had already passed before our solar system was created. Generations upon generations of stars and galaxies predate us and our sun. The vastness of earth's history therefore contacts to something termed "recent". Absurd! My mind rebels at this absurdity and this monstrosity. I am a trained experimental scientist. I do believe these ages. Still, I need something solid, something tangible, something to touch and feel, if only with scientific instruments, so that I can also believe in my heart and marrow as I believe in my brain. I need more evidence.

Timeline of the Universe

Late last month a scientific paper [2] appeared providing some of that evidence. The paper's title is instructive: "Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide". The words "presolar" and "interstellar" suggest matter older than the solar system and originating outside of it. "Dust" suggests solid matter, and "silicon carbide" is a particular type of mineral, one of the first minerals to form in the history of the universe [3]. Presolar grains are not new. What this paper contributes is a new method of dating them. The grains they dated are derived from the Murchison meteorite that landed in Australia in 1969. While most of the meteorite's matter dates from just after the formation of the solar system, embedded within it are trace grains of far older matter, matter containing the mineral silicon carbide (SiC). The oldest grains date to 1 to 5 billion years prior to the solar system's formation, or 5.6 to 9.6 billion years ago. As I touched the meteorite at the local museum, might my hand have come into contact with similar ancient presolar grains [4]?

Should we believe this paper? Key to answering that question is considering carefully the methods used. The authors face two challenges: (1) convincing us that the SiC grains came from outside the solar system and (2) establishing a date for their formation. For (1) the authors relied on a well-established method: demonstrating by mass spectroscopy isotopic anomalies characteristic of matter originating outside of the solar system. For (2) the authors developed a new dating method based on cosmic ray exposure. They had to. As they note in their paper, "Dating of interstellar dust directly with astronomical methods is not possible. Neither is dating based on the decay of long-lived radioactive nuclides, due to current analytical limitations and unknown initial isotopic compositions."

But can we go back even further in time?

Yes, we can go almost all of the way back, back more than 13.6 billion years, if we relax one key assumption. Up to this point, this blog post has been written from a geologist's point of view. What counts to the geologist are minerals, those underlying chemical components of terrestrial rocks, meteorites, and presolar grains. Key to the definition of mineral is the requirement that atoms continuously exist in an intact, regular, and solid structure. Recycling of rocks on earth's surface, for example, reshuffles this structure, thereby resetting a mineral's age to the most recent episode of (re)mineralization.

Chemists, in contrast, see things differently. They are more willing to let go of the requirement that dating apply to elements in their mineral form. What matters is only the elements themselves, and not their chemical neighborhood and bonding partners. All hydrogen, some helium, and traces of lithium were created in the Big Bang and predate even the first stars. Cosmologists estimate that by 379,000 years after the Big Bang, the expanding universe had cooled enough for the nuclei of the hydrogen, helium, and lithium to combine with electrons forming the first atoms.

I sip some tea, and in the water composing it, I taste and consume hydrogen dating back nearly to the Big Bang 13.7 billion years ago. Oh the places that hydrogen has been!


NOTES

1. Missing from the list of eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) is Pluto. Based on its small mass and the aberrant characteristics of its orbit (specifically, its eccentricity and large deviation from the ecliptic), Pluto was reclassified in 2006 from a "planet" to a "dwarf planet", the same status shared by Ceres, one of the larger known asteroids.

2. The article is by Philipp R. Heck et al.  and was published on 28 January 2020 in the Proceedings of the National Academy of Science, 117(4): 1884-1889. The original article is available here at no cost.

3. See Professor Robert Hazen's course, "The Origin and Evolution of Earth" (The Great Courses, 2013), especially lectures four and five. See also the Wikipedia entry on "presolar grains".

4. I am doubtful. The Murchison meteorite, a carbonaceous chondrite, has a composition distinctly different from iron-nickel meteorite displayed at the NM Museum of Natural History and Science.


ACKNOWLEDGMENT

Professor Carol Hill, her course "Planetary Geology" (now being taught at the University of New Mexico), and my fellow classmates motivated and informed this blog post.

posted: 2020-02-20, last modified: 2020-02-20

Sandia Granite and the Abyss of Time

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Granite. Ordinary granite. Its heft weighed in my hands. I rotated the muddy chunk with numb fingers to better examine the clear quartz within. "Intrusive igneous rock", I thought. No magnifying glass was required to make out the hexagonal prisms of quartz's crystals. "Slow-cooling too", I reasoned, for otherwise the crystals would be invisibly tiny to my unaided eye.

In geology, I am a novice, a mere child for whom the slightest glint or sparkle suffices to delight. In my specimen, quartz seems to float in an amorphous matrix of feldspars -- salmon-pink colored orthoclase and white plagioclase -- with black rectangular chunks of biotite, or maybe hornblende, mixed in [1]. With a steel rock hammer, I had just chipped it out of a road cut. That road is the "Old 66", as locals call it, or "NM 333", as the highway department designates it.

Sandia Granite, formed 1.4 billion years ago, from a road cut 
on NM 333 between Albuquerque and Tijeras, NM.

Just east of Albuquerque, Old 66 traverses the geologically-rich Tijeras Canyon. Stretching, rifting, and faulting of the earth's crust in these parts 10 to 20 million years ago uplifted that slow-cooling, subterranean granite, repositioning it overhead as the Sandia Mountains, and opening this Canyon. Here history, both geological and cultural, lurks.

"Along this very road", I thought, imagining Steinbeck's Joad family escaping the Oklahoma Dust Bowl in their overloaded, westbound jalopy. "Salt of the earth, as much as this rock in my hand." Conflating the movie version with the novel, I saw in my mind's eye a young Henry Fonda at the wheel, hungry, lean, and desperate. Old 66 symbolizes America and our restless drive, whether to escape, like the Joads, or instead to celebrate. "Get your kicks on Route 66." I hear that now, in Nat King Cole's cool baritone. And here I was literally walking the very road, rock hammer in hand, collecting specimens, and, yes, getting my kicks.

Wind blew wet and cold for this bleak October day of 2019. Chilling it further was the damp wake of occasional, fast-moving traffic as we worked from the road's narrow shoulder. "Grab your specimens and go", I reminded myself. "Keep focused, keep moving, stay warm, this is only the first of several scheduled stops. Others in the group are already in the car waiting for you." For Professor Carol A. Hill's class "Geology of the Sandia Mountains and the Rio Grande Rift", this was the optional field trip for the hardcore enthusiasts.

"One point four billion years old?", I asked aloud, knowing the number from books [2], as well as from her lectures, yet not quite ready to accept it. "Yes", Professor Hill replied. It is a matter of fact. Granite. Mundane granite, quite literally mundane, removed from the earth with a whack of the hammer. This chunk in my hand is enormously, unimaginably old. That much I understood.

America, our America, in contrast, repels the cling of history, or so it seems. Everything is always changing, wrecked or improved, opinions differ, in any case superseding what came before. Nearby Interstate 40, for instance, has made Old 66 a relic of a former, forgotten era. Long gone are the Art Deco motor lodges and sleek filling stations servicing streamlined cars. And these days, who still remembers Nat King Cole? As our culture forever morphs, these rocks and this earth remain, mute witnesses to it all, biding their time.

I have long worked with unimaginable numbers. Is there anything larger than Avogadro's constant of chemistry, or anything smaller than Planck's constant of physics? Just key them into your calculator using scientific notation. Easy, right? But 1.4 billion years is more than a number. It is also history, geological history, and as history it is a human creation. I ought to be able to feel it in order to fully know it.

One way to comprehend is to temporarily put aside the units -- years -- and only consider the magnitude. America has many billionaires. Can I comprehend their wealth? (Not really. I am satisfied simply to pay off my credit card balance each month.) Instead, as we are concerned with time, what about 1.4 billion seconds? How long might that be? About 44 years, according to my 33 year old HP-15c calculator. That's human middle age. Already, I've lived more than 1.4 billion seconds. That duration I know viscerally. I feel it as aches in my joints and muscles after several hours of hiking.

The relevant quantity, however, is 1.4 billion years. Because there are about 32 million seconds in a year, the age of my granite chunk is equivalent to 32 million middle-aged human lives, stacked end to end. No, I can't comprehend that either.

Another technique is to ignore the number's size and instead locate it in the context of what is already understood. In 2003, I visited the ancient bristlecone pines high in the White Mountains bordering California and Nevada. Immediately, as I walked among these scraggly Methuselahs of trees, I comprehended -- I felt in my marrow -- their 3000 year old age. Younger than the Trojan War I reasoned [3], yet also older than Homer's singing about the War in his epics, the Odyssey and the Iliad. I could understand because the Odyssey I have known and loved since childhood. Some stories of our cultural history evidently endure unchanged.

Earth's history has analogous mileposts. Life emerged on earth between 3.8 and 3.5 billion years ago and, much later, by 0.54 billion years ago life had evolved hard shells that preserved well as fossils. Somewhere within this three billion year span between life and fossils my chunk of granite cooled and solidified from magma. But, unlike the bristlecone pines, I still have no intuition or feeling for the age of the rock in my hand. The distance between the mileposts is just too great.

I am trained as an experimental scientist. I approach geology in that way. On another field trip, to a remote location near Socorro, NM in December 2019, I found a hefty chunk of glassy, translucent crystal [4]. It formed in sheet-like layers, almost like ice. Could it also be quartz? I tried, and succeeded, at scratching it with a knife. No, it definitely was not quartz. Then I watched and listened for what a drop of hydrochloric acid would do. I neither saw nor heard fizzing, so what I had was likely not calcite either. Perhaps unwisely, I licked it. Not salty, so not halite. Using established tests and guide books, using simple instruments like a knife and acid, using my five senses, and using my fallible reasoning, I tentatively conclude that what I found was selenite (crystalline calcium sulfate).

Making 1.4 billion years troublesome to me is its unapproachable abstraction. I can't taste it or try to scratch it. I cannot relate that age to my favorite stories, whether by Steinbeck or by Homer, much less to the voice of Mr. Cole. Sandia granite is found in America but seems not to be of America. I can hold a chunk of it, but I can't fully understand it, not its age. Here, my understanding hits its limits.

Footnotes

1. Sandia "granite" is, more precisely, the granite subtype called granodiorite.

2. For the geology and rock ages, see Jayne Aubele et al., "Geology of the Sandia Mountains", chapter 5 of Field Guide to the Sandia Mountains (edited by Robert Julyan and Mary Stuever), University of New Mexico Press, 2005. For background,  Halka Chronic, Roadside Geology of New Mexico, Mountain Press Publishing Company, 1987, pp. xii-xiii, 27-31, 169-173, is helpful.

3. As I have understood it, the Trojan War was fought between 1200 and 1150 BCE. Homer, if he existed, travelled the Aegean in roughly 750 BCE and, over the course of several long nights, sang the epics to enthralled audiences.

4. This field trip is recounted in an earlier blog post, Land Beneath My Feet.

Posted: 2019-01-08. Updated: 2019-01-08.

President Trump and the Economics of Wind Power

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Call it synchronicity. Sometimes, in the chance meeting of two unrelated events, new understanding emerges. Such was the case with me recently.

Like many Americans, I traveled over the Christmas holidays. These travels found me with a long layover at the Dallas-Fort Worth (DFW) airport. Wandering the terminal to pass time, I came upon a wall plaque announcing that DFW had become a carbon neutral airport, indeed, the largest one in the world. Making it possible was its reliance on renewable energy sources, particularly electricity generated by Texas wind farms.

The other event was a 21 December 2019 speech delivered by President Trump to a conservative political organization in Florida. The President lashed out against "windmills" [1] and the "fumes" they release into the environment. He said [2] --

We’ll have an economy based on wind. I never understood wind. You know, I know windmills very much. I’ve studied it better than anybody. I know it’s very expensive. They’re made in China and Germany mostly — very few made here, almost none. But they’re manufactured tremendous — if you’re into this — tremendous fumes. Gases are spewing into the atmosphere. You know we have a world, right? So the world is tiny compared to the universe. So tremendous, tremendous amount of fumes and everything. You talk about the carbon footprint — fumes are spewing into the air. Right? Spewing. Whether it’s in China, Germany, it’s going into the air. It’s our air, their air, everything — right? So they make these things and then they put them up.

Uniting these two disparate events is the state of Texas. The Lone Star state is a politically conservative "red" state. It has been home of Republican Presidents George H.W. and George W. Bush, and it has deep roots in the oil and gas industry. And yet ... Texas leads all American states in installed wind power capacity. At 27,000 megawatts of capacity, Texas has power to keep the lights on at DFW, and much more. In a distant second place is Iowa at 9000 megawatts. Texas's involvement with wind power began in the early 2000s under then-Governor (now Secretary of Energy) Rick Perry. The state invested heavily in wind power, including some seven billion dollars spent on transmission lines to deliver the electric power.

How can this be? If wind power is "very expensive" as the President claims, then why would anyone -- most of all, Texas -- invest in it? Perhaps Texas is a fluke. But in third place among the states is Oklahoma, at 8000 megawatts capacity. And it too has an economy tied to oil and gas. It too is politically conservative. Of course, strong winds sweep North Texas and Western Oklahoma. But, I think, there is more to it than that. In reporting on DFW's carbon neutral status, The Dallas Morning News notes

Altogether, the airport says it has reduced its carbon emissions by 31,000 metric tons since 2010, with more than half of the savings coming from the switch to purchasing only renewable wind energy. At the same time, the airport's annual energy bill has fallen from $32 million in 2006 to just under $18 million in the most recent fiscal year.

The example of Texas proves the President wrong.  In wind power is money to be saved, and money to be made. Texans know it. And so do I. I found DFW to be comfortably heated, brightly lit, and as pleasant as an airport during the holidays can be. Kudos to Texas!

https://windexchange.energy.gov/maps-data/321

Postscript

In a future post I hope to consider the "fumes" and "gases" the President spoke of. Presumably he meant greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), and water vapor (H₂0). These gases are natural products and essential components of Earth's atmosphere. Without them, earth's average surface temperature would be -18 C (0 F), rather than the current 15 C (59 F). Some greenhouse effect is evidently desirable, even necessary, for life to flourish. However, excess quantities of these gases is believed to be the primary cause of global warming. Crucial here is "excess" and how human activity contributes. The primary gas of concern is carbon dioxide, a byproduct of fossil fuel burning, like that I personally caused by my recent flights to and from DFW. Carbon dioxide concentration in our atmosphere has been steadily rising since the inception of the Industrial Revolution in the early 19th Century. So too have average global temperatures. Wind power -- like solar, hydro, and nuclear power -- emits negligible amounts of greenhouse gases. Surely the President must understand this. That he does not also articulate that is both a shame and a mystery.

Footnotes

1. I assume that by "windmills", the President actually means electricity-generating wind turbines, which, incidentally, was the subject of a recent post to this blog.

2. Because this transcript seems nonsensical, it is helpful also to watch the video of the speech. Whatever he meant to say, the President, through his gestures and tone of voice, communicates unmistakable enmity toward wind power.

Posted: 2019-12-26. Updated: 2019-12-26.

Land Beneath My Feet

Hiking the Quebradas Back Country east of Socorro, NM on 14 December 2019

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Land beneath my feet demands attention. Step upwards watching for the prickly cacti populating this arid country. Step downwards, gingerly, not putting too much weight on that potential stepping stone. Probe it first with your hiking pole. It crumbles at the slightest poke. Gypsum, I finally concluded. It's the stuff of dry wall, and it's all over this place. Cloaked by dark, mossy overgrowth, it is white and crusty, like a snow that's neither cold nor wet. Chunks of it crumble with little effort between my fingers. Pretty sure now of its identity -- plain old calcium sulfate -- I taste it. Not salty, not a trace of halite detected. How strange, I think, to find it here.

One of the advantages to being a beginner, as I am in geology, is the ease at which one is amazed. In my mind, "gypsum" immediately conjures images of White Sands National Monument. It is found in the Tularosa Basin 120 miles to the southeast. Its white sands are not the usual quartz sand but rather finely-powdered gypsum, blown by a steady westerly wind, from playa into the Monument's vast field of ever-shifting dunes.

Playa are flat lake beds thirsty dry much of the year. Lacking a natural outlet, playa water escapes by evaporation, abandoning its load of dissolved mineral solute as a crust of opaque, white gypsum and translucent crystals of selenite. Elsewhere in the American Southwest, other evaporite minerals, such as borax and trona, are found on vast, flat, desiccated lake beds. Searles Lake in California comes to mind. I remember my time there, the afternoon April sun becoming blinding in its reflecting off the crunchy white surface under foot.

Once this New Mexican land too must have been flat. Once. Long ago. Long, long enough ago for time's slow subsequent actions to accumulate, eventually altering the land and forming the rugged terrain over which I climb over now. By folding and faulting, lifting up and eroding down, moving by wind blowing, depositing by water flowing, and wasting by gravity falling, the landscape inevitably changes. "Once" might be 160 million years ago, in the middle Jurassic Period, that is, during the heydey of the dinosaurs, for, as geologists say, New Mexico was then submerged beneath a huge Lake Todilto [1]. Something -- but what? -- must changed the climate, making it drier and hotter, leaving Lake Todilto to shrink, shrivel, and disappear. Perhaps the gypsum here precipitated then.

By four miles in, of seven miles total, and my knees are feeling it, all of the stepping and zigzagging up, down, and around. We are hiking in the Quebradas back country roughly seven miles due east of Socorro, New Mexico. "Quebradas" is apt, for the word denotes a ravine, especially one formed by an arroyo. I wash down a couple of ibuprofen tablets with what water I have left. Of the dozen of us on this hike, I am one of the quiet ones. I want to read the landscape and understand its deep time history. Anyway, lacking both grandchildren soon to be born or even adult children recently married, I have little to contribute to conversations heard around me. My family history goes longer. My children are all adopted. They are elements of the Periodic Table born in the exploding death throes of ancient stars predating the birth, by hydrogen fusion ignition, of our own sun 4.6 billion years ago. From all of that sound and fury comes the calcium, the sulfur, and the oxygen composing this soft gypsum and the land beneath my feet.

Footnotes
1. Ancient Lake Todilto may have only covered what today is southern Colorado and northern New Mexico. If so, it would not explain gypsum deposition near Socorro. An alternative source of evaporative gypsum deposition is the disappearance of a vast sea covering southern New Mexico in the Permian Period, 286 to 245 million years ago. See Halka Chronic, Roadside Geology of New Mexico, 1987, pp. xiii, 28, 201,

posted: 2019-12-16, last edited: 2019-12-16