omenti

a legend

Adm Grace Hopper is of the heroes of early computing.  In addition to making fundamental contributions to software, she was one of the few who started to realize what technological change impacted people.  Recently some of the security folks - notably Bruce Schneier and Steve Bellovin - learned about a general talk she gave at the NSA in 1982.  They hounded the NSA to declassify and publish the talks and here they are!  They give a sense of what the world was like then and you can sense her brilliance.   This was a year before ARPANET cutover to TCP/IP, which many consider the real start of the Internet (although it goes back 13 years earlier in one form or another).  Perhaps there's something you can take away.  

Side story: About 12 years ago I found myself spitting into the wind trying to deal with climate deniers who lacked a technical background.  One of her papers gave a good description of what we now call sealioning. It was a good enough argument to convince me to move on and try other channels.  She also wrote about dealing with people like Trump who use bullshit asymmetry - what is known as Brandolini's law these days.  A very wise woman indeed!

 

 

 

the aether and ethernet

I just came across a piece by Om celebrating Ethernet's 50th birthday. A must-read if you don't know the history of this foundational technology.  Bob Metcalfe called it Ethernet as a play on the luminiferous aether that was used to explain how light could populate through the universe

 

I won't go into how the concept of the luminiferous aether came about, other than it was something of a hack that was needed given the knowledge of the day even though it was clear much about it was wrong.  Science is full of explanations that become dated with new discoveries.  Sometimes the old models work so well that they still find use for calculations and pedagogy.  Newtonian mechanics is still used in intro physics and is good enough for SpaceX, but falls apart for the map on your smartphone. 

 

By the mid 19th century issues with the luminiferous aether were beginning to fill books.  Issues that made it appear more like magic than science.  It had to be a fluid to completely fill space, it had to be massless,  it had to be billions of times stiffer than steel and have zero viscosity, it had to be perfectly transparent, and so on.  Most people would probably say "we don't understand it", ignore thinking about it and just proceed with what they had the tools to work on. 

 

A few experimentalists tried to prove or disprove its existence. Michelson and Morley showed there was no difference in the speed of light caused by the motion of the solar system.  That and Einstein's Special Theory of Relativity pretty much put a nail in the coffin of the luminiferous aether.  The vacuum of space back then was a void.

 

All well and good except it isn't.

 

Michael Faraday, playing around with electricity and magnetism nearly two hundred years ago, had the remarkable insight to think of electric and magnetic fields to explain how electric charges and magnets worked at a distance.  He didn't have the math to create a robust theory, but his insight is one of those astonishing events that changed history and one of the great moments in science.  Next, around the time of the American Civil War, James Clerk Maxwell published his equations - the first field theory that united the electric and magnetic forces.  

 

The move to towards field theories in fundamental physics continued and Quantum Field Theory is the most accurate theory in all of science.  The Standard Model, how we think about the Universe (except for gravity) is a collection of about 17 fields (depending on how you count) - one is associated with each fundamental particle.  "Particle" as a tiny ball that might be charged or have some other property isn't what's happening.  Rather there's a field that fills space for each type of particle.  Electromagnetism uses two - the photon and electron fields.  Neutrons and protons use up and down quark fields, the Higgs field basically allows the universe as we know it to exist, and so on..

 

What we think of a particle is an excitation of the appropriate field.  A proton is something we learn about in grade school.  It isn't fundamental, but rather made of three quarks.¹ So a proton is a collection of up and down quark excitations.  To a physicist the vacuum isn't a void.. it contains all of these fields.  If unexcited there won't be a particle (although they crackle with virtual creation and extinction all the time .. so fast that you mostly don't note it), but if you whack the vacuum hard enough, there's enough energy to excite one or more of the fields and a particle appears.   The large hadron collider is able to concentrate enormous amounts of energy in tiny spaces to do just that - whack the vacuum.

 

So the universe is filled with these fields - it's fair to think of them as a fluid of sorts.  The view of an aether is a nice description of the vacuum, except the banishment of the luminiferous aether as made the use of the term taboo.  

__________

¹ A proton is much more complex than just three quarks, but for the purpose of a non-technical description.  And further on there are some deep mysteries about the vacuum indicating there's much to learn.  

 

 

bondi blue

a minipost

Ask elite beach volleyball players to name their favorite beach and Bondi Beach often comes up.  The sand isn't world class, but the water - that amazing blue - can take your breath away.  There's a bit of a controversy on pronunciation, but I've heard an Australian player go with bond-eye.

 

About twenty five years ago Steve Jobs had to bring Apple back from its near-death experience.  There wasn't much in the way of in-house new technology, but Jobs had Jony Ive as well as his own taste.  They went with the iMac.  A strangely shaped, but very cute, little computer with a semi-translucent bondi blue case.  Pundits noted there wasn't anything new except design and pronounced it and Apple dead on arrival.  Apple sold enough to buy time for for the transition to an operating system and later a processor migration (one of two!), all the time working on "company-killing" products like a portable music player and a smartphone. 

 

The surprise success of the iMac set off a tidal wave of design element copycats.  Suddenly everything from routers to hair dryers sported translucent cases - often in bondi blue.  As far as I can tell the new design language didn't case a sensation in any of the non-Apple markets.

In the past month I've seen partly thought-out plans to include LLMs like ChatGPT in some way into existing or newly dreamed up products.  None of them were clearly articulated. Somehow ChatGPT or an equivalent would supply the appropriate magic.  LLMs have become the new bondi blue (bondization?)  There are clear usage cases as well as those that aren't.  I suspect a lot of money will be burned with a single digit survival rate .. sort of what one sees during Cambrian explosions.  

 

I won't comment here on the dangers of these technologies other than noting regulation is necessary with a well-defined "open", ownership of rights to all training data, evolution of regulation, etc.  History across many industries tells us industry shouldn't be involved in its own regulation.  

 

 

 

tesla mythology

Every now and again I try to post something on the history of science, technology, or math - at least in the areas where I've spent time with primary sources or history of science and technology classes. My first director at Bell Labs was big on the history of science and engineering, encouraging us to take a series of courses offered at Rutgers. Such courses are important, but far too rare. One counts as one of my favorite undergrad classes:  'Engineering disasters of the first part of the 20th century'.

 

My problem is keeping such pieces short and to the point. Nikola Tesla is someone I've started writing about at least three times before bailing as there was too much for an hour or so of writing.  Another issue is much of the folklore is wrong. As an electrical engineer he was incredibly intuitive, but his understanding of the underlying physics was often somewhere between wrong and batsh*t crazy.  It seemed like to much to deal with.

 

This short video on Tesla touches the high points and  is consistent with a course I had along with a lot of reading from the period.  The course was great.   Looking at the period from from from Michael Faraday through Philo Farnsworth, it touched on the physics, engineering and the business interests that drove the middle and later parts of the period.  Describing the period as colorful would be understatement.  

 

Reality doesn't diminish my respect for Tesla - it's just he wasn't what popular myth suggests. And a side note.  I spent about three years at Brookhaven National Laboratory on Long Island.  The remains of the old Tesla tower is nearby, protected by a too  easily scaled fence:-)

 

To the video - it's a short must-watch piece.

unexpected arcs

Three weeks ago breathless reports on the 'breakeven' fusion event at the National Ignition Facility began to appear.  While a remarkable achievement, it's more a marker of progress along a long and difficult path rather than an event promising a hopeful turn in decarbonizing the energy supply. 

 

Nuclear fusion has been hyped since the late 1950s.  Fission based reactors turned out to be straightforward.  All you had to do was refine uranium ore and then control a reaction to heat water and run an otherwise conventional power plant.  The cold war led to any number of atoms for peace projects suggesting a nuclear everything future.  The realization that nuclear fusion was much more efficient and "cleaner" than fission led to optimism and work on controlled fusion.  After all, it happens all the time in stars doesn't it?

 

Power from nuclear fusion has been twenty years in the future ever since.   Science and technology have made serious progress, but the challenges are great.  There's also the issue of cost per kilowatt-hour. If you build a plant that produces more power than it takes to run it, will it be economically competitive with other low or no-carbon solutions? 

 

There's a simple invention → development → application → change arc of technology mindset that doesn't describe the real world. It turns out you can travel a good distance along the arc only to see failure.  The garage-worthy helicopter, supersonic airliners and dirigibles have all be built and commercialized, but have failed for a number of reasons that are likely to keep new versions failing for the foreseeable future.  Somehow the dream factor persists in many of these and new failures continue to rhyme.

 

There are hugely successful inventions that have solved a problem, but turn out to have a deadly flaw that caused great harm.  DDT,  chlorofluorocarbons and leaded gasoline are obvious examples.  Less obvious are inefficient transportation.  Standardizing on 3,500+ pound vehicles to move people a handful of miles on average trips has led to millions of traffic deaths, a large pollution toll and a structuring of infrastructure and where and how people live that is proving difficult to change even though much better choices exist.  Sometimes tend to fire, aim and then look for damage around the target.  Sometimes it takes decades and change is expensive. 

 

There are a wishlist class of inventions where some progress is made, but effective deployment is a long way off (fusion power plants)  or unlikely as the underlying approaches are flawed at this point (self-driving cars, hyperloops, neural implants, space elevators, nuclear powered cars and airplanes, etc.)

 

It's very easy for an imaginative artist or writer to sketch an idea that is technically impossible.  We have a tendency to sort through the chaff and find amazing predictions from a hundred years ago.  It's useful to realize how much noise there is and that these things didn't happen in the author's or their children's lifetimes.  Still - every now and again you run across something that stops you.  This is one of my favorites - not only because it suggests wireless video communications, but it also nails the social element of two people ignoring each other so they can look at a screen.

 

Then there's a class of necessary arcs that we need to get past application and into wide-spread use.  Flexible power distribution to move power from generation to where it can be stored or used.  An advanced worldwide pandemic monitoring system.  Water management and treatment to deal with changing local climates as well as use needs.  More efficient agriculture that can deal with changing climates.  Changes to transportation and housing infrastructures that are less damaging.  Some of these aren't terribly sexy, but require social and political will - areas where progress is often very difficult.  And in the background there needs to be investment in fundamental science.  While progress can be difficult to predict, historically it's easy to predict that there will be unexpected discovery that can lead to something useful down the road.

 

It's fun to enjoy the stories writers and artists weave.  Creating your own is a great way to work with the imagination of a nine year old on a rainy day. Time and interstellar travel won't come along with scores of other ideas that help move stories along.  

 

 

repairability

My Dad was a Ford man.  More specifically the Ford Falcon.  It was a simple compact car with a 170 cubic inch displacement straight six coupled to a three speed manual transmission.  It scored on the high end of the Mobil fuel economy test - about 19 miles per gallon when the average sedan was in the 12 to 14 range.   But what he really liked about it was how repairable it was.  Not only was it simple to work on, but most of his friends had cars with the same engine and transmission.  If something needed fixing we could usually do it ourselves using tools borrowed from one of his friends.  For more serious repairs there were specialized tools from Strobel's A to Z Rental, garages or (shudder) the Ford dealer.

 

The simplicity of cars of the day was balanced by crude manufacturing tolerances.  Pistons fit so poorly in the cylinders that the first 500 or 1000 miles were done with great care using an abrasive oil to polish the parts into shape.  It made a big difference in gas mileage and extending the life of the engine past 50,000 miles.  

 

The dual gas shocks of the 70s opened the market for better cars that used higher precision design and manufacturing processes.  That and the beginnings of cars that crumpled to absorb energy in crashes made simple repair much more difficult.  The amateur mechanic had largely vanished by the 80s.

 

Clothing and shoes were expensive back then.  Quality construction and repairability were important considerations while shopping.  Tailors and dress makers were common.  The same was true for appliances.  Vacuum cleaners, toasters and anything electronic could be repaired at home or the local repair shop. 

 

There are exceptions today .. Jheri makes her own clothing or buys high quality pieces with the intention of buying very little as she hopes each piece will last at least a decade.  She's abandoned fashion and has created a style very much her own.  I suspect some of you - Om for example - have a similar philosophy.    But while it can be done in clothing, it's next to impossible when electronics are involved.

 

By the time I was fourteen I had three or four black and white TVs.  None of them worked - watching TV wasn't interesting.  The tubes, capacitors, transformers, switches and so on..  now those were useful!  I designed and built a few radios and a stereo amplifier.   It was straightforward and the experience taught me a lot about electronics.  Now I look in a computer, TV or radio and see only massive integration.  It's still possible to build things, but design is much more difficult. Learning about circuit elements is probably better done with computer simulations.   

 

The right to repair movement has grown in recent years.  I welcome  it for some products, but given the tight integration of hardware and software  I worry it may not be as generally attractive as proponents claim.  

 

Smartphones are a case in point. Apple is infamous for discouraging third party repair.  You can order a kit from Ifixit to replace a screen, battery and some other parts.  It can work well if you have a bit of experience and Ifitit is upfront with the degree of difficultly. You lack the tools and technique to take apart, replace and reassemble the device to design specifications.  

 

My personal results are mixed.  I easily replaced the battery (twice!) on my first day, first generation iPod.  The battery and screen on my out of warranty iPhone 5 was a different matter.   After five hours of frustration I was left with an operating phone, but the case was fitting tightly and whatever waterproofness was gone.   The misaligned case also interfered with the physical buttons on the side.  I did get another year and a half from the phone though.   It could be worse.  I know someone who replaced the battery on an Android phone with an inexpensive battery from Amazon.  The phone got very hot during charging and caught on fire when he took it apart to pull the battery out.  It filled his place with acrid smoke, but fortunately only destroyed the phone and wastebasket

 

Apple is afraid of regulation so they offer repair kits for some of their devices.   The Verge documented a battery replacement.  You get a huge repair kit with a large hold on your credit card until Apple gets the kit back.  The process probably works well if you're skilled at working with small electronic devices, but this isn't for everyone. Given the cost of shipping I suspect Apple's losing money, but they're also trying to make a point of what it takes to do a high quality repair.  Of course a third party repair shop could buy the tools and perform quality repairs and I suspect that will happen.  Lower quality shops abound, but your phone or laptop may be a bit wonky afterwards.

 

We need to understand what's repairable, what's sort of repairable, and what's not.  Easy to repair smartphones have been offered but they're generally expensive and lacking in features.  I suspect smartphones, laptops and smartwatches are probably moving to a subscription model anyway.  Clothing and some appliances could made for longer lifetimes and repairability.  Then again convincing consumers and companies to move away from a consumption model is a huge, but very important, challenge. 

 

I've mentioned clothing, but should follow-up with other product areas where design for long life, repairability and upgrading is important. It's generally expensive, but in the long run can have advantages.  You may live in an example.

 

 

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. 

 

a thread of ev history

There's a nice vantage point in  Point Loma in San Diego with a monument to Juan Rodriguez Cabrillo.  In 1542 he made the first contact with the indigenous people of the area.  Not much happened, but sailing Northwards a few days later he noted smoke hanging over what is now Los Angeles.  Enough that he called one of the bays  Baya de los Fumos - Bay of the Smokes.

 

It's not clear what caused the smoke.  The Los Angeles region hosts three types of temperature inversions, each capable of trapping air masses close to the ground allowing smoke to build.  The region may have had one of the highest population density in North America in the 16th century, so it's possible the smoke was from thousands of fires - the region certainly held smoke in later centuries.  It's also possible there were large fires in the hillsides fanned by Santa Anna winds.

 

Before WWII Los Angeles, apart from areas around chemical plants, had fairly clear air most of the time.   That all changed after the war and by the fifties a thick brownish much often dropped visibility to a few blocks.  The brown smog was different from either smoke produced by wood fueled fires or the smogs coal burning was know for.

 

While the LA area was a natural environment for temperature inversions, it also hosted centers of intellectual curiosity.  A few years after the war Los Angeles decided to tackle the problem and created the first air pollution district in the country.  Arie Jan Haagen-Smit of Caltech managed to figure out what it was by 1950.  Sorting out how it was produced took a few more years.   He was able to show eighty percent came from  the automobile.

 

Caltech became a breading ground for ideas to deal with automotive smog.  By the mid 1960s Haagen-Smit and others were thinking about modern incarnations of electric cars. Wally Rippel was a student fascinated by the idea of electrifying transportation. His aha moment came when he showed electrifying the automotive fleet would only require a twenty percent increase in electricity generation.  (the number today is considerably less than ten percent). Wanting to move things along Rippel did what any Caltech student would do.  He challenged MIT to a race.

 

The Caltech team added over a ton of lead acid batteries to an old VW van for the Pasadena → Cambridge trip, while MIT converted a Corvair for their trip to Pasadena. MIT finished about a day and a half faster, but they broke down several times requiring towing more than once. The van, on the other hand, just motored through without incident and were declared winners.  

 

The 70s saw further development at several engineering schools. Recognizing batteries were heavy,  Caltech worked on early hybrid cars that would drive short distances on power from smaller battery packs before starting up a gasoline engine.  Along the way they develope regenerative braking to boost efficiency.  The first energy crises hammered home the idea that efficiency was important.  A Scientific American article appeared in 1973 telling the story of efficiency and declaring a person on a bicycle one of the most efficient forms of transportation in nature .. Steve Jobs later riffed on that calling personal computers bicycles for the mind.  An electric bike would be about twice as efficient as a human powered bike.  That led to work on motors and controllers. Unfortunately the American book disappeared and plans for a safe cycling infrastructure died.  Electric bikes would have to wait a few decades.

 

 

 

In the 80s Rippel was working with Paul MacCready's AeroVironment, something of a Caltech spinoff, on a specialized, almost anything goes, solar powered car for the five day World Solar Challenge race in Australia.  GM footed the bill for Sunraycer team and the car buried the competition.  GM engineering worked with them and the collaboration continued.  Learnings from the solar races went into new motor and controller designs as well as a recognition that aerodynamics were very important gave people the feeling something practical could be done.  Enthusiasm within GM's engineering community talked the company into building the EV1 - the first production modern electric car .  GM corporate didn't know what to do with it.. much has been written on how and why the project was killed after three years of production and extremely enthusiastic customers. Other than its batteries, the EV1 was more sophisticated than current electric cars.

 

Rippel and a few others from the EV1 experience founded AC Propulsion, building a demonstrator called the tzero.  More a proof of concept, it was sportscar designed to impress wealthy tech types defeating a stream of Ferraris and Porsches along the way. Martin Eberhard tried to convince them to take it to production, but the jump in scale was too much for them.  Instead he co-founded a company called Tesla well before Musk entered the scene.

 

Electric car history has many threads.  I'm familiar with this as I heard bits and pieces in school and through people I know.   The deeper story requires many more angles, but it's sticking how much can take place with just a few people.

 

I'm a believer in efficiency and infrastructure.  Moving towards safe active transport (walking, cycling and e-bikes) offers a much greater improvement over conventional electric cars.  (long story, willing to argue) 

 

A bit of early history. International Rectifier funded a solar car project in 1960.  Silicon solar cells were still very new and exotic.  IR provided solar cells to the space program, but wanted to grow a commercial market.  Doing the math they realized powering a home would be incredibly expensive, but a short range vehicle for city use might be practical earlier.  To make a statement they sent a solar panel to Charles Escoffery who converted a 1912 Baker Electric.  The world's first useable solar car.

Finally the clean air work starting at Caltech lead to catalytic convertors, reformulated gasoline and any number of environment regulation that have saved many lives.  That work was an innovation. 

 

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...

__________

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.

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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!