Our viewers was this younger Black-Topped Evening Heron (Nycticorax nycticorax), Oakland’s official metropolis chicken.
I sat down the opposite day for an interview with Liam O’Donoghue, producer of the exemplary East Bay Yesterday podcast. I had thought forward about what he would possibly ask, after all, however didn’t assume he’d ask me to outline plate tectonics, an all-encompassing Idea of the Earth, in a soundbite method.
I can talk about the small print of plate tectonics all day with out repeating myself, as a result of I’ve soaked within the literature for 50 years. In my guide I attempted to attenuate that whereas staying true to the science, avoiding lazy cliches and saying not more than what was completely mandatory. I spent days boiling it down to a couple important pages. How might I ship an “elevator pitch” model on the spot?
What I got here up with could not make it into the ultimate audio, but it surely went one thing like this.
The Earth is scorching and gooey on the within and chilly and brittle on the surface. The within half, regardless of being made principally of stable rock, manages to maneuver and stir, considerably just like the contents of a pot on a range. And the surface half, cooled by the chilly of outer area, responds considerably just like the floor of a cup of espresso as you blow on it. Between these two influences, cooling from above and heating from beneath, the onerous outer crust breaks into a couple of dozen massive segments, known as plates though they’re actually curved shells, and Oakland sits the place two of these plates rub towards one another.
Most discussions of plate tectonics don’t go this fashion; they begin by itemizing the completely different working elements after which describe how they work together, then they inform how that every one interprets into different options on the Earth’s floor like mountains, oceans, volcano chains and so forth. Additionally they recount the historical past of how we arrived at this idea. The free opengeology.com textbook An Introduction to Geology, a sound textual content written by skilled lecturers, does it that method. To my thoughts, this bottom-up method has by no means been straightforward to digest, though critical geology college students have to be taught all of it. I believe it displays the best way, traditionally, that plate tectonics was first found.
I choose to begin with the gist. It begins on increased floor, and it leads on to an intellectually thrilling frontier in astronomy: Earth-like exoplanets that revolve round different stars. The newest technology of telescopes has proven us rising numbers of worlds much like ours — small, with stable surfaces and comparatively skinny atmospheres. As we be taught extra about these planets, we must always be capable to distinguish the signatures of various tectonic types within the gentle they mirror towards us.
Earth hasn’t all the time had plate tectonics. The proof is delicate and the arguments are intricate, however Earth behaved in another way for its first billion years (or two or three billion relying on completely different strains of proof). And within the subsequent billion years (or two or three), plate tectonics ought to come to a halt. Is that this typical? Having just one specimen useful, we don’t know.
The identical method we labored out the final life historical past of stars by 1000’s of them, of random ages, so we ought to have the ability to do the identical for planets like our personal. Do they undergo the identical phases as Earth? If that’s the case, what’s the final timetable, and if not, what different potentialities has nature discovered? The solutions are ready for future scientists to find them.
After which drilling down from this elevator-pitch model of plate tectonics, it’s a brief attain to grasp the scenario in Oakland: We stay the place two plates are transferring previous one another, alongside the Hayward fault. The Hayward fault is certainly one of a number of faults prefer it on both aspect, together with the San Andreas fault on the west and the Calaveras and Harmony faults on the east. Collectively, these make up the boundary between the North America plate and the Pacific plate.
What’s easy to explain within the elevator pitch is extra complicated shut up. I image the plate boundary as a set of a number of freight trains on parallel tracks very shut — too shut — to one another, rolling the identical path at completely different speeds. The tracks are so previous and rickety that the automobiles maintain swaying and colliding with the subsequent prepare over. This analogy helps me perceive the long-term results on the panorama alongside the plate boundary over the previous few tens of thousands and thousands of years: the rise of the Coast Vary. I believe that will get the gist, too.
PS: Twelve years in the past I wrote a barely longer piece, “About Plate Tectonics,” for the positioning now often called ThoughtCo.com, that also reads effectively. (They took it down in 2016.) I prevented the historic method there, too.
For these with entry to Naomi Oreskes’ 2001 essay assortment Plate Tectonics: An Insider’s Historical past of the Trendy Idea of the Earth, David Sandwell’s fantastic essay “A Martian View of Plate Tectonics” imagines how the idea might have been assembled in an alternate historical past based mostly purely on satellite tv for pc observations. His publically out there draft is fairly near the printed model, and simply as refreshing.
