omenti

fusion!

The short version is it’s a remarkable technical and scientific achievement. Controlled human-made power from fission is easy - last week marked the 80th anniversary of the first reactor. Fusion - what powers the stars - is much more difficult on Earth. The necessary temperatures are far greater than those found in most stars. A star like the Sun gets away with a very slow and low power density reaction that would be impractical for generating power on Earth. It turns out the power density of the core of the Sun is about a quarter of your metabolic density and close to that of a lizard. To get around this different fuels are needed along with much higher temperatures. Still, if you can only figure it out, it sounds like the perfect goal - fuel from water and no radioactive waste.

 

The first serious attempt at magnetic confinement look place about 60 years ago .. it, along with every other effect until this last week failed. Those that achieved fusion required more input power than the power they produced. The figure of merit is Q: the ratio of the power of the fusion reaction divided by the power required to ignite and sustain it.

 

The laser confinement experiment announced focused a short pulse of light - about a billionth of a second - from 192 lasers onto a small gold container that vaporized to generate x-rays that collapsed a diamond coated fuel pellet of deuterium and tritium. The power of the laser light was 2.05 MJ (megajoules — a gallon of gasoline is 121 MJ, a hot dog in a bun is about 1.5 MJ) and the fusion explosion yielded 3.15 MJ. A Q of about 1.5. What isn’t mentioned is the efficiency of the lasers or the facility isn’t included - or the efficiency of extraction power from the miniblast. The lasers are less than one percent efficient so you can see there’s a long way to go.

 

This facility has been running for about a dozen years. It has been solving enormous engineering and applied science problems along the way as well as contributing to the pure science of understanding plasmas at this scale and temperature. Even the fuel pellets are very difficult to make and test. They have to be extraordinary symmetrical and most are rejected in testing - usable pellets are very expensive.  What has been achieved is not a prototype, but rather a triumph of instrumentation technology along with the control of some difficult to manage parameters. 

 

Moving this line of fusion forward seems like a long shot. A factor of five improvement may be possible with a redesign, but they need more than a thousand. Not impossible, but there’s a long path ahead.

 

There are other design types that confine microwave heated plasmas. Getting it right and working will take many years - probably decades and then there’s the issue of what does a facility cost compared to other types of power stations.

 

I hope work goes forward, but not at the cost of workable technologies that address global warming *now*. There’s so much that can be done, but very little political will.

 

2 december 1942 - a half watt

4:00 PM 2-Dec-1942

Compton: The Italian navigator has landed in the New World.

Conant: How were the natives?

Compton: Very friendly

 

Almost exactly 80 years ago the first human-made self sustaining nuclear reaction took place under the stands of a vacant football field at the University of Chicago.  It's a remarkable story and something of a race with Nazi Germany.  Fortunately so many competent physicists had fled Germany that the Nazi bomb project was a failure.  It turns out the wikipedia article on the subject is an accurate and readable summary of the dawn of the pre-manhattan project effort to get a handle on nuclear fission.  The piece  gets a bit technical here and there, but you can skip over those parts if you like.  I'll try and give a high level view of what a sustained reaction is without going into the quantum mechanics of the process.

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Nuclear fission is the process where the nucleus of an atom breaks apart into smaller pieces releasing energy (often quite a bit) in the process.  The nucleus of an atom is a tight cluster made up of positively charged protons and electrically neutral neutrons.

All of those positive changes packed together - you might ask why don't they fly apart? After all, electromagnetism causes like charges repel.  It turns out a very strong force, cleverly called the strong force, acts on neutrons and protons binding them together.  A difference between the two forces becomes important.  Electromagnetism is a long range force while the strong force only acts over short subatomic distances. To first order you can think of the strong force acting only between immediate neighbors while the electromagnetic force acts on all of the protons.

If the nucleus gets big enough the total repulsive electromagnetic force of all of the protons overcomes the closest-neighbor strong force and breaks the nucleus up in to smaller pieces releasing energy in the process (nuclear fission)

Most of the elements we're used to have nuclei that are too small to break up on their own.  A few are on the borderline. In the case of uranium the addition of a single neutron is enough to undergo fission and in the process it releases energy and, on average somewhat more than two extra neutrons along with a couple of nuclei that are smaller than uranium.¹

In nature uranium usually isn't concentrated and the neutrons from fission are absorbed by other materials.² But if you concentrate uranium you get to a point where each fission has a high probability of striking another uranium nucleus and so on - creating a sustained reaction. Unchecked, with enough purity, and you get an atomic bomb. At lower concentrations and with the ability control the amount of neutron absorption you get a controlled nuclear reactor that liberates a useful amount of energy.

 

A number of interesting characters were involved in these early experiments.  Enrico Fermi was the key player in the first sustained reaction.  Physics was getting specialized and he was probably the last physicist who was both a great theorist and experimentalist. 

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¹ I've left out a lot.  I haven't mentioned which isotope of uranium for example.  Also - you may have noticed that adding an extra neutron shouldn't increase the electromagnetic force as the neutron is neutral.  It turns out the uranium nuclei is so close to breaking up that the kinetic energy of the addition neutron adds just enough to break things up.  A nice example is adding a neutron to U-235.  One possible fission chain  n + U-235 → Rb-92 + Cs-140 + 3n + 200 MeV of energy. 

Also details of the strong force weren't known at the time..  A clear hypothesis didn't arrive until about 30 years later and deeper details of the mechanism took almost thirty more..

² A natural formations of uranium t pure enough to initiate sustained nuclear reactions was discovered in Gabon.  It operated for a few hundred thousand years producing less than a megawatt of power.  

 

 

who are you going to call?

Drop two pieces of bread into the toaster and push the lever down.  You go about your business getting the rest of breakfast ready and then, after a few minutes, two pieces of toast pop up.  Have you ever thought about what's going on?

 

We usually think about the toaster receiving the bread and giving it back to us after a few minutes - electric heating somehow.  Someone from a few thousand years ago might wonder where the bread came from and what kind of magic transformed it into something similar but different after a few minutes.  He might wonder if the lever was some kind of prayer or incantation.  We can examine the process at a variety of levels and can find considerable depth.  We know the cord is plugged into a socket which has a path though a series of transformers and wires that usually lead to a generator that is turned by spinning a turbine with falling water or steam superheated by nuclear fission or the burning of fossil fuels.  When the switch goes on the load on the generators increases by a bit more than we're using.  The steps required advances small and large over the decades in science and technology.   For example getting the of generation and transmission of electricity to work efficiently depends on an understanding of Maxwell's equations and a fair amount of math.  

 

We don't think about these things because we trust them. There's a solid bedrock of reliable knowledge in much of our technology even though we're not one hundred percent sure of the science.  Our trust in science is nearly universal even though some of us chose to deny certain aspects.  Global warming deniers and flat earthers have no problem using the Internet - computer mediated communication built on silicon based semiconductor technology, fiber optics and much more.   Their mistrust is often based on something in their personal value system that to first order may seem orthogonal to the scientific arguments.

 

Not many people have a good handle on how science is done and how it progresses.  Many of us had to memorize the steps in "the scientific process" in elementary school, but it turns out it's messy and there's no formal process.  In college you may have come across Karl Popper's notion of falsifiability and Thomas Kuhn’s paradigm shifts. Both of these models have been shown to be wrong.  The view among many scientists and philosophers of science is science is more or less makeshift, but produces reliable knowledge and tends towards self-correction and reliable knowledge over time.

 

A few years ago a few lectures by Naomi Oreskes at Princeton gave me the basis of something I'm more comfortable with even though it's not complete. She argues reliable knowledge is based on five factors:  method, evidence,  consensus, values and humility.  I won't go into these as each is a deep subject, suffice it to say that the last three are deeply social - something many "hard" scientists tend to have a difficult time admitting.  Science is deeply collaborative and these social aspects often determine what is worked on as well as how it, and the people who did it, are perceived. 

 

Although most people trust much of science, personal and group values can get in the way of trusting certain aspects as well as certain scientists.  We've witnessed this up close with the pandemic, global warming and evolution.  I worry that many scientists have made a mistake by hiding their values (that's changing with some of us) as well as separating science and technology.  The separation of science and technology was value based and began to become dominant after WWII. Somehow science was to be the pure pursuit of nature even though it's linked to technology at the hip.  Often technologists are well versed in the science underlying their work and some venture into applied science.  Scientists, particularly experimentalists, are by necessity amateur technologists.  I've done some technology and have a bit of a feel for it, but I'm certainly not skilled - I do much better on the science side.  I'm in as much awe of great technologists as I am of great scientists. 

 

A final point.  Who should you trust to do science?  If the light in your house keep going out when you plug the toaster in, it probably makes sense to call a licensed electrician.  When a pipe in your house bursts spewing out gallons per minute, you call a licensed plumber and not an electrician or dentist. A trip to the dentist and not the Ghostbusters is in order when you hit a cherry pit in a piece of pie and a tooth falls out.  And when you're thinking of the long term - say your children's lives - listening to experts on global warming makes sense while listening to Mobil-Exxon or the Farmer's Almanac doesn't.  In each of these areas there are mostly good players and a few bad ones. You find the good ones from the consensus of their community. 

 

building blocks

Watching Apple's Mac Studio announcement yesterday took my mind to something Carl Sagan said in the Cosmos series.

The Mac Studio's underlying technology goes far beyond the many tens of thousands of person-hours Apple has invested.  The semiconductor industry that stands on the shoulders of Bell Laboratories back to the fundamental work of James Clerk Maxwell and before.  Apple and others are able to come up with advances that strike us as dramatic as they make an impact on our lives.  The impact of some innovations like the electric light, the telephone, the automobile, powered flight, radio, the atomic bomb and the Internet have changed how we see ourselves.   But take a look and they're all built on long chains of invention and innovation that are often forgotten.

 

This comes to mind with the horrors going on in Ukraine.  Russia has always had brilliant minds.  They've made stunning advances in physics and math, but they haven't been as successful as the West in building on that.  A good deal of their technology is derivative.  In the past 25 years this may be by design. Most of the export value comes from extraction - oil and other natural resources. These industries seem to fall under the direct control of Putin's friends.  More technical industries are still under oligarchs, but these aren't super high profit.  As long as the core players can control them, the real focus of the economy is what can be run by shear force and power rather than technology and sound business practices.  (note - this is speculation as I'm certainly not a Russian expert..  so take it with a grain of salt).  

 

High tech industry is required for the military and some consumer use.  Although that is supposed to be home-brew there is a lot of importing and rebranding. I've seen that in electronics used in physics experiments and am told is standard operating procedure.

 

So imagine you can't important and rebrand the CNC tools necessary to make jet engines.  Can you make the tools yourself. What if you can't even make precision bearings?  What if China doesn't allow electronics into the country (they probably will, but now they can be the Mafia dons)?  Sanctions can make a medium and longterm impact.  

 

You don't need to make your Apple pies from scratch - we have our universe - but few companies or countries have the capability to build objects of the modern world without technologies that exist outside.  All of these long threads few of us think about until they aren't available.  Think about all of those high value products waiting for fifty cent ICs that were designed twenty years ago...

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PS - I'd love a Mac Studio, but it's way beyond my budget. 

 

 

orbits

It's almost Perihelion Day!   I may wish people Happy New Year, but the beginning of a calendar year is artificial, so I celebrate a specific point in our orbit every year.

 

The orbit of the Earth is elliptical. Not terribly so, but enough we're about 5.1 million kilometers closer to the Sun in early January than we are in early July.  The closest point is the perihelion and the furthest, the aphelion.  The exact time of perihelion varies from year to year - this year it's the 4^th of January at 6:52am UT or 1:52am EST.  Californias get to celebrate on the 3^rd.

 

At perihelion the Earth is at its fastest speed in our orbit - 30.29 kilometers per second.  At aphelion, the slowest point, we've slowed by about a kilometer per second.  Given its closeness, the apparent disk of the Sun has about 7% more area at perihelion than it does at aphelion.  That seems to bother people as it's Winter in the Northern Hemisphere.  In fact the Earth is a bit more than 2°C colder at perihelion than at aphelion - an artifact of the distribution of the continents and a bit of physics.

 

There more land in the Northern than the Southern Hemisphere.  Water has a higher heat capacity than land.  Think about a desert.  During the day it can get scorching hot, but it rapidly cools off at night.  The ground doesn't hold heat as well as water.  In July the Northern Hemisphere has long days that allow the land to heat up for longer periods raising the temperature of the air above it and raising the average temperature of the Earth in the process.   In January the Southern Hemisphere is getting the most sunlight, but most of it falls on water, which doesn't heat up as much as the land. 

 

There are some interesting rabbit holes one can get into and much can be learned by studying the positions of bodies in our solar system and people have been doing it for thousands of year.   Some civilizations were very sophisticated in calculating and predicting astronomical events even though their models of the solar system were wrong.  An early computer that makes your jaw drop is the Antikythera mechanism.  People have been studying it for over a century and Scientific American has a fine summary of what's currently known about the device.

 

In 1900 diver Elias Stadiatis, clad in a copper and brass helmet and a heavy canvas suit, emerged from the sea shaking in fear and mumbling about a “heap of dead naked people.” He was among a group of Greek divers from the Eastern Mediterranean island of Symi who were searching for natural sponges. They had sheltered from a violent storm near the tiny island of Antikythera, between Crete and mainland Greece. When the storm subsided, they dived for sponges and chanced on a shipwreck full of Greek treasures—the most significant wreck from the ancient world to have been found up to that point. The “dead naked people” were marble sculptures scattered on the seafloor, along with many other artifacts. Soon after, their discovery prompted the first major underwater archaeological dig in history.

One object recovered from the site, a lump the size of a large dictionary, initially escaped notice amid more exciting finds. Months later, however, at the National Archaeological Museum in Athens, the lump broke apart, revealing bronze precision gearwheels the size of coins. According to historical knowledge at the time, gears like these should not have appeared in ancient Greece, or anywhere else in the world, until many centuries after the shipwreck. The find generated huge controversy.

...

 

A more technical discussion appears in a recent article in Nature (open access)

 

A Model of the Cosmos in the ancient Greek Antikythera Mechanism

Tony Freeth, David Higgon, Aris Dacanalis, Lindsay MacDonald, Myrto Georgakopoulou & Adam Wojcik

The Antikythera Mechanism, an ancient Greek astronomical calculator, has challenged researchers since its discovery in 1901. Now split into 82 fragments, only a third of the original survives, including 30 corroded bronze gearwheels. Microfocus X-ray Computed Tomography (X-ray CT) in 2005 decoded the structure of the rear of the machine but the front remained largely unresolved. X-ray CT also revealed inscriptions describing the motions of the Sun, Moon and all five planets known in antiquity and how they were displayed at the front as an ancient Greek Cosmos. Inscriptions specifying complex planetary periods forced new thinking on the mechanization of this Cosmos, but no previous reconstruction has come close to matching the data. Our discoveries lead to a new model, satisfying and explaining the evidence. Solving this complex 3D puzzle reveals a creation of genius— combining cycles from Babylonian astronomy, mathematics from Plato’s Academy and ancient Greek astronomical theories.

 

Back to now.  Happy Perihelion Day to all of you!

and a comment

I'm  not fond of the idea of the Earth making a circuit every year as, the Earth never comes back to the same spot in any reference frame.  It's roughly close enough for most, but in four dimensional space time it's something of an approximate helix expanding out along the time axis.  You can never go home. Good enough reason to look forward!

 

 

 

 

 

meshes and trees

A few weeks ago an unexpected email arrived from Germany.  A physics postdoc and had come across an ancient transition radiation detector in storage at CERN a few months before.  It seemed like it could be useful in an experiment her group was thinking about. She had a few questions and it turned out I was the best person to talk to.

 

Many people think science is done with sparkling new state-of-the-art kit.  A few pieces perhaps, but very old equipment is updated, repaired and repurposed where it might be useful.  An experiment I was part of in the early 80s required a very large magnet.  The best bet was one that had been a cyclotron at Berkeley fifty years earlier.  It worked well,  but we had to tap into institutional knowledge that had migrated out of physics entirely.  That knowledge combined with technology that hadn't been invented at the time gave us something fantastic.  

 

I have no idea how my old detector made its way from Brookhaven National Laboratories to CERN.  The documentation and lab books were packed with it, but they made assumptions that the people who built it would be involved.   That meant me.  I asked for photos of some of the lab book pages and then it came back.  I listened to her ideas, offered some suggestions and wished we had her experience back then..  Of course that experience came years later.

 

These interactions spanning several decades may not be common, but twenty year interactions of hardware, software and people.  It's all a mesh.  Old apparatus islands that have been repurposed and grafted onto new apparatus.  It's an organic process that's difficult to map out and impossible to predict.   Diagrams it would look like flocks of meshes that are grafted together with a lot of institutional knowledge.  No one has a complete picture and local expertise is critical.  A team sport spanning decades.  It isn't easy, but it works.

 

Last week I came across something by Frank Oppenheimer in the 30s:

 

 

 

It's one of the better commentaries I've seen on how science progresses.  The same is probably true for many other fields.  I suspect it's true for any infrastructure involved in messy and complex endeavors where creativity and insight come into play.  

 

I've been fascinated watching the techno-solutionist approach to cities - the so-called smart city.  These are often based on a "start with internet and build up" model.  They try to measure everything and automate control.  Sensors embedded everywhere and tree-like computational structures making decisions to smooth out - well - everything.  A fundamental problem is we don't know what is being measured and what the biases - social and technical - are.   A simple truth I've learned from my exposure to sports science is you have to know exactly what's being measured and exactly where it is useful. (duh!)   Often current measurements and/or models just don't work.  Something complex like a city is that on steroids with the tree-like information structures introducing a certain rigidity.

 

There are a few types of people who thrive in the messy environment of a city.  Impedance matchers - those who can connect and explain across disciplines, and synthesizers come to mind.  (many others too - artists for example)  They respond to intellectual and system friction and help spark creativity. They're ground zero essentials for  creativity and invention.  I have doubts that the techno-solutionist cities can be terribly creative in the long run.

a song by Malvina Reynolds comes to mind

 

opportunity++

Now it's posh, but London's Soho district was a rather unfortunate place in the mid 19th century.  The region was experiencing dramatic growth, but it didn't connect to London's sewer system.  Residences crammed in with slaughter houses and rendering plants overloaded a primitive sewer system that was unable to serve everyone.  Cesspools ran over and untreated waste flowed directly into the Thames.  This was taking place during a worldwide pandemic. London had seen outbreaks before, but the 1854  outbreak on Broad Street changed the course of history.

 

John Snow is famous for mapping out cholera deaths in the area and noting a cluster served by a water pump on Broad Street. The pump drew water from a well that was contaminated by human and animal sewage. The Broad Street pump was removed from service, but didn't make much of a dent in the three or four thousand cholera deaths in London.  What made a difference was what he did next. - an analysis of deaths in regions served by water pumped from the Thames.  He set up a double blind experiment and showed cholera was carried by an agent in the water rather than the dominate theory that it was "bad air" (miasma).  It was the beginning of scientific epidemiology and modern public health. 

 

There's a pub named in his honor near the location of the pump that started his line of reasoning.

 

Over the last year and a half we've been  learning just how important public health is.  It seems odd to unquestionaingly spend so much on a war industry when a pandemic mixed with politics and a fear of science has prove more lethal than war.  That aside we're learning fresh air is critical with airborne spread diseases.  During an outbreak that means masks universally worn as a first and final line of defense and frequent air changes.  With the delta variant of SARS-CoV-2  it looks like you need at least fifteen air changes an hour to qualify as safe with minimal masking.  Outside of clean rooms and operating theaters that's a tall order indoors.  We can get part of the way there with in-room air cleaners, upgraded HVAC systems and opening windows when you can.  I've been spending some time doing this to learn a bit and have come to the conclusion that, although effective, it's sort of a piano wire and chewing gum approach.   Real fixes require an architectural design approach informed by science to create new spaces as well as retrofit existing ones.  Very few people do the science and much needs to be done.  New technologies probably need to be developed and there needs to be a better understanding of what can be done with what exists.. 

 

Creating clean spaces goes well beyond the current pandemic.  Clean indoor rooms can have an impact on the flu plus there are a number of chemicals that outgas that we mostly ignore.  And many of us have had to deal with PM 2.5 pollution from forest fires and combustion.    The question is how do you make this desirable enough that we learn how to make and implement better designs than we have?   How do you spark a revolution in public health that involves architecture design and retrofit on a massive scale?

 

Unfortunately successful public health measures are often seen as expensive overkill.  Perhaps carbon dioxide concentration is the answer.  Over the years studies have shown decreases in cognitive functions and alertness linked to higher  CO₂ concentrations.¹ Generally 1000 parts per million is seen as a boundary, but some studies show decreased mental ability around 800 ppm.  Many offices and schools regularly exceed 1000 when occupied.  Your car is probably several thousand in a half hour  if you aren't bringing in outside air.  How much would a school spend to upgrade the mental ability of its students?  Would a company pay extra for more alert workers who function at higher cognitive levels and get sick less often? And what about homes?  Many homes are worse than offices - maybe working from home should be rethought or at least certified.   

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¹ A fairly recent study on cognitive function associated with CO₂ and VOC exposure 

 

 

the universe has it in for computers

a minipost

Cosmic rays have fascinated me since I was 13 and found a detector with a couple of patient physicists on the summit of Sulphur Mountain in Banff.   That was my first exposure to relativity.  I written a few posts on cosmics, but just say the word if you ever want to get me started on particles that can have the energy of a fastball and require detectors spread over thousands of square kilometers to properly detect.   Smashing into molecules in the upper atmosphere they produce large showers of elementary particles.  These can make it to the ground - or to a memory chip in a computer.  A direct hit on a memory cell can flip a bit from 1 to 0 without damaging the memory.  It's why you don't locate computer animation companies in Albuquerque or Denver.  It's why you use ECC memory in computers that run programs for more than a few hours and why many spacecraft have multiple radiation-hardened computers.   In addition to computer problems they're responsible for a large number of biological mutations.  They're one of many reasons why I think it's nutty to send humans into space beyond near Earth orbit. 

 

It's a very rich topic and this video by Derek Muller is an excellent introduction with historical examples of problems.  They've even interfered with an election. 

low distortion rearview mirrors

 

History Does Not Repeat Itself, But It Rhymes

      -  Mark Twain

Except it wasn't him.  

His clever and prolific writing made people assume he said it even though he never did.  It turns out it first appears around 1970 in a poem by a Canadian artist named Robert Colombo.  When asked if he knew where it was from Colombo couldn't recall other than he might have seen it in a literary section of the New York Times a few years earlier.  In fact it appears with and without attribution several times around the time of Colombo's poem in the early 70s.   That said, a hundred years from now people will still think Twain said it.

 

The process of science is much messier than the simple order kids learn in school.   There are too many dependancies to list.  A few philosophers of science  - notably Karl Popper and Thomas Kuhn - have tried to describe how scientific revolutions and change happens.  The how, where and why of scientific change.  Kuhn and Popper are somewhat at odds.  Kuhn's ideas were popularized and are still taught as how scientific revolutions happen.  It turns out that both of the frameworks are deeply flawed and have fallen from favor with serious students of the history and philosophy of science.  I came to it late, but I'm more a fan of an earlier step - trying to understand some of the history of science. 

 

Unfortunately the history of science is often neglected in scientific training.  Students are told a few selective stories from the great revolutionaries without much context.  Experiments, theories and techniques are described with little background.  The struggle and small steps forward and backward are  missing.  The world seems much too messy when you start doing real science on your own.  (this is probably true in many fields!)

 

One gets bits and pieces of local history from the last generation or two in their subfield.  This can be very powerful. I learned a lot about the development of the atomic bomb as some of the people I studied with were parts of the Manhattan Project.  You need to learn the importance of failure as well as hunches and the need to distrust your own work.  

 

The history of science, like the history of art or music,  is a story of the development of ideas that can be appreciated by non-specialists.   There are some wonderful books out there.  The trigger for this post was one of them:  Einstein's Fridge by Paul Sen.  I know the technical area well, but have big holes in my understanding of how all of this came about.  If you can follow articles in the New York Times science section, you'll learn a lot of what the physics is saying without the math and how it changed the world.  He gives a very simple, but accurate, description of entropy and has the best description of photosynthesis I've seen that doesn't get into biochemistry.  The historical motivations make it come alive.  I'm stealing some of his clear descriptions.

 

Most of this is probably true in many other fields.  About twenty years ago a friend invited me to dinner with Maurice Wilkes - his grand advisor.  Even though Maurice was in his late eighties the discussion went on late into the night and continued on two more occasions. I'm not a computer scientist or engineer, but Maurice is a physicist who happened to invent a good deal of the fundamentals of computing that's still in use.  Hearing him talk about the early history and the connections to our shared background made it all come alive.  The problems computers had to solve as well as the nuts and bolts of designing one - provided a wonderfully rich learning experience.  There was this hint of how the great mind of this humble person worked. A good history book can provide that kind of experience.

 

 

the fundamentals

mini-post

The Standard Model of Physics dates back to the mid 70s and is far and away the most complete and accurate description of three of the four forces of Nature.  Add General Relativity for gravity you have the basis to  answer fundamental questions like what we're made of and the forces. That's the bedrock of physics.    (the Standard Model with General Relativity tacked on is sometimes called Core Theory)  It's something that almost every physicist wants to see fail as there are hints of something deeper.

It's very elegant physics with beautiful mathematics, but good enough non-technical descriptions aren't easy.  Here's the best short discussion I've seen.  

 

I should note that while physics can describe all of these interactions, there's a problem with calculation.  Our mathematical techniques are often too weak so we have to resort to clever and not so clever approximations.  A lot of physics turns out to be applied mathematics.