omenti

objects and friction

Randall Munroe's xkcd is a necessary visit for anyone doing science, math, or engineering.   Artistically simple, he often sums things up with an almost poetic simplicity. Some have suggested topic ideas - he's taken two of mine and created beautifully distilled views of the underlying concepts that make me envious of his talent.  And he does it about three times a week.   Every now and again he creates something that resonates across a community.    It happened again last week:

 

 

Anyone who reads a lot of scientific papers recognizes this. Dozens of variations emerged overnight.  Some were very specialized - at least three relevant to astrophysics alone and I only know that because I know the community.    Here's one Abeba Birhane posted.¹

 

 

Serious truth!  A good deal of the community is this clueless.

It made me think of friction and objects.

 

One of the most remarkable features of physics is its simplicity.  While it may be non-intuitive and sometimes requires a bit of tricky math, you can remove complexity and discover underlying bedrock.  Once you understand the simple basics you can restore the complicating bits a piece at a time and describe a vast set of physical processes.  The fact that you can deconstruct and reconstruct so effortlessly is unique among the sciences.  It's why a physicist will tell you physics is the simplest science.  

 

Beyond physics complexity and emergent properties become important.  It turns out that asking "what is life?" is one of the most difficult questions. Working backwards from biology to biochemistry to chemistry to physics breaks down along the way.

But back to simplicity 

Students learning about motion and collisions start with a statement like "assume a frictionless surface."  Concepts become clear and it's easy to describe interactions where everything is understood.  Two blocks colliding elastically for example.  Later on you can restore friction.  Mechanical engineers, working in the real world,  are forced to deal with it.  In some of their systems - say a chain and gear bicycle transmission - it's possible to have efficiencies that exceed 99%.  Frictionless is the ideal here.  On the other hand you don't want frictionless tires or brakes - you'd never start and, if somehow put in motion, you couldn't stop.  The bicycle and road system is complicated enough that friction is good in places.  Fortunately good engineers know how to deal with such things.

 

The concept of "frictionless" has extended to interactions between computational objects and people.  In fact people are often treated as objects that contain a long series of properties.  Constructions like these lack the meaningful emergence that social creatures have. Serendipity and insight are often the result of social "frictions" in our interactions with other people.   We can have simple low friction interactions.  Sometimes they're great as we're not looking for much, but they're generally shallow.  A worry is large scale machine learning can create a faux sense that interactions with machines are deeper than they really are.  And many of these interactions are with other parties who make decisions about and for us. 

 

A few who build large scale social platforms have deep backgrounds in the social sciences and the humanities and think deeply about underlying social issues, but much of it is done without much clue by coders who build things quickly and then iterate to make them better - often more frictionless.  

 

Separately I had two wonderful reports from people at a very creative company.  Fully vaccinated people are back at the office with some precaution and maskless outside.  One reported she's had more insight and exciting ideas in the last week than in the last six months - largely through random talks with coworkers where they could "read" each other.  I hope all of you find the light at the end of the tunnel soon.

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¹ She's a cognitive scientist from Ethiopia who specializes in critical race theory - a rather important intersection these days.

 

 

 

the education question

Last week I sent a note to regular readers:

 

Perhaps it’s a sense that things are possible post-pandemic, but I’ve been asked for comments on the future of education three times since the beginning of the year. While I have some unscientific and undoubtedly biased thoughts I’m happy to share it occurs to me this group is exceptionally diverse.

So the request: Could you write a bit about what you’d like to see in education going forward? The subject is huge and readers represent at least seven countries so just pick a few and stay away from clear needs in some countries - like affordable and equitable education. Those are incredibly important, but perhaps some thoughts on curriculum, teaching, etc.. I’ll collect and post them with my comments in a week - say a cutoff on the 24^th of April. Let me know if you want your name attached or not. And don’t worry about it if you don’t have time.

 

Here are the responses in order of arrival:

 

I could write too much on this but one thing I think should be focused on is an increase and improvement of vocational education including changing the name and giving it an equal or near equal standing with so called academic education. With the rapid changes in technology there are numerous supporting jobs required and they must be trained for. I would also like to change the word Engineering to Applied science and technology which might attract more women and others who have a fear or not so great feeling about "Engineering" .......................you asked for it there are many other things like required mentoring in High school, more use of the case method in all education fields...... good question

Ed Hajim

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Thanks for the request, Steve!

I think fixing the existing bureaucracy of schooling is a fool's errand, so I'm more interested in creating a scaffolding that helps anyone learn, at any time, with others not gated by their common age, etc. We've created many kinds of artificial scarcity where abundance exists.

With that in mind, if you have the time, I'd route you to my TEDx talk, then the Vegas talk I did right after, which dovetails into the first one, then my Brain on the Hidden Curriculum of Schooling and Great Design Questions Unschooling Raises.

Happy to talk about any of the above at any moment :)

Jerry Michalski

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As a grandparent who has primary care of two elementary school aged children, I have observed, obsessed and have a lot to comment on public education in my city, Seattle.

Our system is at once both profoundly broken and resilient.

Broken? A system that refused to use a complexity lens to plan and be able to respond to changing contexts. (And appears to have NOT been planning all along, but I don't know if that is true. They appear to operate with a fixed mindset. A mechanical mindset.When the governor set a deadline to return to school, the resulting design reflected a reaction versus a design ready for complex contexts. (The lowest common denominator?)

Resilient? The teachers and learning specialists who spend every ounce of their beings supporting their students (this is not ALL teachers, but we have been blessed with ones who have been AMAZING and have saved our collective sanity. Thank you Nadia, Michelle, Kendra, Stephanie, and many more...)

Broken is a system where children of color don't want to come back into the classroom for all the racism they endured before and during the pandemic. How is it we are shocked to hear this?

Resilient? The advocates for children with special needs, for communities of color, LBGTQ, and for families sapped by Covid-related financial and emotional losses. The people who have wrapped families as best they could with food, services, support and compassion.

The resilient people are resilient. Well supported families adapted in the pandemic with home based learning, bought the additional services their children needed/wanted, and when and where they had to, made sacrifices around their own work and parenting roles. Barely skipping a beat they continued their quest to get their kids "into a good college." Yup, the system they want is one that provides the path to a good college. They make the system work for their families or they go to private school. It is a sort of bootstrap mindset for white upper-middle and upper class families. "You can make it work if you do the work!" And they donate to the PTA so they are also addressing all the ills of the system. Yeah, right. But have we leveraged white privilege to redeem the school district? I don't think so. And lump me in there as often I crumble at the depth of need and the brokenness of the system.

Broken is a system so weirdly funded that when pressed to bring back students into the classroom, the caveat is "and sorry, transportation only for those federally mandated." (Note: this example is one of cascading impact. Bus drivers laid off, weird funding approaches and what might be perceived different motivations to remove choice options from the system by denying transportation.) A system that responds to loud, privileged parents who want their kids out of the house now. How is that an option for working families and single parents, particularly those with children in multiple schools? (Broken, in that the district has poor understanding and management of their own budget and yet resist audits and insights, preferring to spend money on PR to make things look good.)

Resilient? Parents who try and set up, moderate and endure Facebook support groups (that are often hijacked) that try and serve as a critical connection points (neighborhood car pools, walking busses?) even if the data shared is often wrong. (What happened to data???)

Broken is a state leadership that says schools MUST OPEN for the mental health of students, and yet the state nor the district provides funding for additional physical or mental health services (or has to cut them due to budget shortfalls), offers no support to families struggling with the mental health needs of their children beyond a link to a help line (not the school district's), and diminishes students who must stay or choose to stay remote by hyping those who are returning to the classrooms.

Our systems are designed based on outdated, broken financing models, labor/management relationships that have deteriorated over time into spaces of zero trust and constant battles, and the instantiation of our profound, national racism.

There is no better time to reinvent, not just tinker. To do that, however, we have to re-prioritize socially and financially the role of public education for all. We can't have schools funded on real-estate taxes which continue to thread red lines through our communities. And those of us with means CANNOT WALK AWAY.

Nancy White

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I think the focus on making students a product for companies is wrong.  The skills someone might need in 10 or 15 years may be very different.  I'd like to see school focus learning how to learn rather than memorizing facts that may not be facts.  At least some of it needs to be fun and play is overlooked.  Play's where you find your passion.  For people not going to college I like apprentice systems like the German and Danish systems.   

In Alberta we had streaming. Kids were assigned to groups by what they thought was ability.    They must have thought it would be easier to put me in the slowest group because I'm deaf.   We were the kids who were constantly reminded we'd never amount to anything.   On top of that  kids and even some of the staff bullied me because I look unusual.  My parents didn't know enough to advocate for me.  Some children fall through the floor.  I'd like to see that fixed.  

Oh - I want people like Steve to teach math and science:-)

Jheri

 

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I've written quite a bit on what I think is important assuming the issues Nancy points out can be addressed, so I'll spare you.  Get in touch if you'd ever like to talk about it. But one thing..

 

The first time I was in my grad school mentor's office I noticed something on the top left of his blackboard

Knowledge is acquired and never bestowed

It was always there. 

 

aerosol transmission

minipost

 

The American Physical Society had a webinar on aerosol covid transmission.   Jose Jimenez of the University of Colorado at Boulder is an aerosol physics expert.    It’s not terribly technical, but the first 45 minutes is probably mostly for public health and medical types. Much  is making the case for about 80% of covid transmission being aerosol rather than droplet.  This was an issue until a few months ago as the WHO and CDC believed it was mostly droplet.  It turns out that was based on a flawed study that is almost 50 years old!  They’ve since recanted.

 

 

Starting around 45m he goes into recommendations.   As always the best bet is to avoid them if people you don’t live with are present or have recently been inside.  With aerosols stagnant air is a problem so you want good ventilation if others are involved.  It turns out CO₂ level in a room is a good enough proxy for aerosol concentration.  Sit in a car with three other people, windows up, and after a short amount of time you’re breathing each other’s air and the CO₂ levels are sky high. Open a window and turn on the ventilation and the levels come down.  He wants to see CO₂ meters in all enclosed public spaces so you can decide what might be safe or not or how long you can be inside.  He’s not a virologist, but some are recommending 700 ppm as a guideline (I've seen 600 mentioned).

 

 

Good enough detectors based on NDIR are in the $100 to $200 range.  It's a very simple technology that uses the fact that carbon dioxide strongly absorbs a specific frequency of  infrared light.  They’re only good +/-50 ppm, but that’s good enough.   Of course all of this has to be balanced with the infection levels in your community.  

 

postscript

 

Several readers asked for CO₂ meter recommendations. I can make a few recommendations, but have only used a few.  Stay away from sub $100 units is the only rule of thumb I can offer.  Schools should have them in each room as well as stores, offices and so on.   You probably don't need one in your home unless you’re curious or want to see how well your windows and HVAC system are working (that can be a big issue).

 

The seminar talks about airplanes. Air exchanges per hour are very high when the ventilation system is on so airborne infection risk is low inside the cabin.  The rest of the trip is questionable - very high levels were found in jetways for example. New York subway trains have good air exchange rates, but I haven’t seen any work on the platforms. Buses vary and I’d be suspicious when the heaters are on in the Winter. I’ve measured a variety of cars. With windows up and two occupants CO₂ levels were over 3500 ppm in twenty minutes. That’s extremely dangerous if one of the occupants is contagious. Opening windows helps, but cars vary. The effect isn’t big on very streamlined cars like Teslas. On aerodynamically dirtier cars opening rear windows canincrease air exchange more than front windows as the outside air pressure on a moving car increases towards the rear of the vehicle. You should also turn on air circulation. With just circulation I got readings around 900 ppm and the best readings with windows were in the 700s.  I’d stay away from any car if someone outside of your bubble is in it.

 

An interesting note is some measurements have been done on cognitive ability and alertness. Over 1500 ppm and people become less alert.  That can have an impact on the quality of work as well as high attention activities like driving. The few studies that have looked at cognitive ability show declines with increasing CO₂ levels.  One study saw the decline start around 800 ppm and another around 1500 ppm.  Neither study was gold standard robust, but I suspect the effect is real - certainly alertness is real.  Many school rooms, offices and homes are normally over those levels so your may want to make changes even after the pandemic.

 

 

scribbler moon

Margaret Atwood

David Mitchell

Elif Shafak

Han Kang

Karl Ove Knausgaard

Ocean Vuong

 

Each of these authors has taken a walk through Nordmarka Forest in Norway to place a their manuscript in a special room in the Deichman Library.  Ninety four more will follow.  The authors are specially chosen for their imagination and the stories are to based on the themes of imagination and time.  No one other than the authors will see their words until 2114.   In that year someone who doesn't exist now will take each of the 100 manuscripts from their containers and prepare them for printing on paper made from 1,000 one hundred year old Norwegian spruces that were planted just before the Margret Atwood took the first walk through the forest. 

 

The Future Library project was created to stir the imagination and give hope.  A century is a good time period - just outside an average human lifespan, but not so long as to be unimaginable. What will be around? Will people care?  

Our greatest responsibility is to be good ancestors - Jonas Salk

 

We live with a number of legacies - a written language, medicine, science, religion, weapons, slavery, pollution. ... some good and some bad. Mostly we live in the present and don't think much about the leverage we have in creating future legacies. Some legacies happen by default.  Humans are one of the few species with a sense of the future.  Projects like the Future Library spark wonder and perhaps give us hope that maybe we can make a difference.  Perhaps a trick is to think about time scales and what we might accomplish.

 

You can do something for yourself on a smaller scale. Here's one of mine:   My thesis advisor gave me his favorite slide rule when I received my Ph.D. It had been given to him by his advisor when he received his.  It became my favorite.  I used it regularly and wondered about the legacy of calculations that were used to build conjectures and hypothesis through their careers.  Every now and again I wondered what I'd do with it.  About twenty years ago a very unusual Summer student came along.  Art and computer science, she ended up at an animation company.  In slide rule had been used for a certain type of story telling..  small corners of the fundamentals of Nature.  I gave it to her some time ago so I could enjoy the link between the past and the future.  One type of story telling changing into another.  She says it's very special to her and gets use for calculations used in making films that tell stories.  Wondering who she gives it to and what path and stories it might inspire gives me pleasure and hope.

 

In my work I have to think of a variety of time scales.  Some events at the subatomic level take place in a under a billionth of a billionth of a second.  At the scale of the Universe some things have been around for billions of years and will be around much much longer.  These times so foreign as to be abstract.  A few weeks ago one of you sent a note from the Grand Canyon that was filled with wonder inspired by that slow geological process that created it.  Wonderful experiences to stir the imagination.  We should seek out these experiences, but I find staying in human time scales and thinking about and building legacies lets me live in a slightly better future and gives me hope.    Set your mind some distance in the future and think of something good you'd like to see there or something bad you'd like to change.  With a target maybe you can imagine a path and help work towards it.  It gives us a way to not discount future people and their world.

 

Scribbler Moon?  That's the title of Margaret Atwood's book you won't read, but maybe your great great grandkid will..

 

how big is switzerland?

Rey-k-javík

The big test was would come at the end of May.  Sixth grade and we had to identify countries and their capitals on a world map.  That meant spelling everything correctly and adding some countries not on the list for extra credit.   I wasn't good at spelling then and it seems to have gone downhill since, but the unit was fun as our teacher had been around Europe and was a good story teller.  She also wanted to make the point that maps lie - that various projections color our impressions and even doing something simple like measuring an area on a Mercator projection was difficult.  A few weeks later the question came that I kept visiting for a few decades. 

 

How is the area of a country measured?  Is it considered a flat surface, or do you measure it on a sphere (I didn't know about the shape of the Earth then), or what about uneven ground?  What do you do about tides?  Shared lakes (like some of the Great Lakes)?  How do you measure a coastline? 

 

My parents tolerated this for awhile and then it was off to the library.  There wasn't much on this, but visits to libraries are never wasted. 

 

Over the years bits and pieces came when I wasn't looking. I first encountered fractals in Scientific American and followed up with Mandelbrot's paper . The measure of a coastline became finally became clear. There was an inherent fuzziness and you had to choose a scale.  And he had developed some beautiful mathematics that got at the heart of the matter - what is a fractional dimension?

 

A countries area is usually defined as the outline of the country projected onto the Earth's geoid or ellipsoid (there isn't standardization, but using the ellipsoid is probably good enough). In other words the so-of spherical nature of the Earth is used.  High tide marks boundaries, interior bodies of water are included in the area, but uneven terrain isn't accounted for.  The terrain bit made me want to see what the impact would be.   About ten years ago I found a dataset of terrain altitudes for the planet on a 100 meter grid. I used these with some detailed country outline data and looked at a few countries.  The Netherlands only gains a tiny bit of area.  The US grows by almost two percent, but Switzerland was slightly more than seven percent larger.  That's big enough to make Switzerland larger than Denmark and the Netherlands.   I didn't have good data for places like Nepal and Bhutan - they'd be spectacular.  And imagine looking at Manhattan with a one meter grid...  Its area would grow enormously.  

 

One of those questions a kid can wonder about that gets quite involved and requires standards be set. 

 

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Simple Summer Pasta and Tomatoes

For many of us this is peak tomato season.  In late August years ago I had a very simple tomato and pasta dish. The tomatoes were in chucks and not really cooked. It would only work if they were perfect so I gave it a try. Here is about what I did. This would be enough for two hungry people or four people if served as a side course.  It's more of a narration than a conventional recipe. 

Two really amazingly blimpishly ripe tomatoes that are going to have great flavor. If you can, go with heirloom tomatoes as the new ones have so much goodness bred out of them. My guess is I had maybe about one and a half pounds of tomato. Chop these into half inch pieces and scape them into a bowl making sure to recover some of the juice left on the cutting board.

Pour to glugs of a good extra virgin olive oil over the tomatoes.  Sprinkle on a good finishing salt (Malden is great) and freshly ground pepper before gently stirring to mix.  Set the bowl aside. 

Start some water boiling for the pasta and throw some salt in. Cheap salt of course

Now chop a strong red onion into slivers. Maybe about a quarter cup

Chop a handful of good arugula

Cook about a half pound of pasta (I like a quality thick spaghetti for this, but pick your favorite) and try to stay away from the marinating tomatoes

Layer the onions on top of the tomatoes and then make a layer of arugula choppings

Dump the cooked pasta onto the layered mixture in the bowl and give it two or three minutes to heat up a bit. To deal with the frustration grate some parmesan for a topping. (I prefer it cheeseless, but most people probably want it). The heat from the pasta is slightly cooking the ingredients beneath, just barely, but perfectly enough.

Gently mix and serve.

 

companies that care

Recently a heard a podcast on what it means for a company, or employee, to be a steward.  It could be any number of things - relationships, society, the environment. All good, but not many large companies seem to exemplify this beyond PR efforts.  But some smaller organizations are good at this.  I'll mention one - you can probably think of a few on your own. 

 

I'm not athletic but enjoy rowing as an exercise.  In the early 90s I found myself with a used Concept 2 model B rowing ergometer. It had been abused and needed a serious clearing and a few replacement parts.  Calling the company I found myself talking to the product engineer responsible for its design.  He asked some questions and said he'd send a parts list.  A few days later a box arrived with very clear repair sheets and the parts.  The bill of sale said $0.00.  I started the repair, but one of the old parts was bent and I was afraid of damaging the unit.  Another call and he talked me through the repair.  I asked what the parts cost and was told that wasn't a big deal, he was just happy to see one of his old machines being used. 

 

The old model B still works well.  It was made in 1986 and has seen more or less daily use since the repair in  1995.  I've had to buy some parts for standard wear and tear over the years.  They aren't expensive and the company stocks parts for every machine they've made.  The phone support is always friendly and free. 

 

Their ergs work well and I've probably generated a half dozen sales - word of mouth and gym experience are their big referrals. They're the standard erg in college rowing programs and the sport of competitive erg rowing has grown organically within the user base.  They also make most of the oars used in Olympic class competitions.  A combination of design, execution, support and general friendliness makes them one of my favorite companies.   Here's a piece about them from twenty years ago.

 

(the image is of an ancient model B like mine - newer ones look different, but are functionally about the same)

 

Feel free to write about your favorite in the comments section.  Are there any that will be making people happy and the world a better place fifty years down the road?  How about any that are publicly traded?  Is there a size ceiling? 

 

 

 

the small things that make you happy

Pip Coburn and his circle have a practice of sharing "anti pet peeves" - those little things that bring a smile and a bit of happiness. It's a good practice these days.  I had one today and sent it to him and Om Malik.  Om suggested I post it.   Feel free to add your own reason to smile in the comment section.

 

We live next to a large piece of undeveloped swampland. It’s full of deer paths and a mixture of heavily wooded and open areas. For about seventeen years I’ve taken a ninety minute walk around noon when I’m working from home. Today is worth writing about - my vulture returned!

About six years ago a female turkey vulture began to accompany me. She’d wait on a telephone pole where the woods cleared or sometimes she’d spiral down from the sky. For nearly a kilometer I’d walk through a large open area and she’d follow along, making short flights from telephone pole to telephone pole. . Then I’d disappear into a heavily wooded around for about thirty minutes before coming back to the clearing. She’d be waiting and together we’d make our way through the open space - regular partners for nearly four seasons.

Then nothing…

I kept looking and even got in touch with the Raptor Trust in case they had taken in an injured vulture, but after a month assumed she had left the area. Hopefully by her own choice.

Today - mirabile dictu - she reappeared. She only followed me one way, but it was so nice to see an old friend.

 

 

lightning in a bottle

Last week I had my first face to face group meeting since early March. Seven of us set up lawn chairs in a distanced circle on a beautiful lawn.  Apart from not being able to hear each other without speaking up and needing something better to draw on, it was wonderful.  I could talk about the out of band signals that face ot face conversation has, but something else struck me.  Our group tells stories and listens.  We have a real dialog - our group is smarter than the smartest individual. 

 

Dialog was one of the terms the social science group I was associated with banned.  Many people equate dialog with debate.  My favorite way to communicate with small groups (often one other person) is to have a dialog.  We tell stories and listen to each other discovering and learning about each other and ourselves along the way. Both of us can be smarter than each of us as individuals.   Debate - where one person says something and the other challenges  - is the opposite of dialog.  It attempts to convince.  When people with different strongly held opinions engage in debate both parties are dragged into the mud.  Debate fuels emotion and happens to be easy to jump into and highly addictive.   It's a form of communication that is easily weaponized with the aid of machine learning to promote engagement and sell advertising. 

 

Social media platforms focus on social comparison, competition, competition, unsupervised debate and so on. Some allow isolated groups where learning and dialog can place, but tools rarely support that and these groups depend on excellent moderation to survive. 

 

Zoom and other conversation tools have a lot of warts, but allow open conversation that can be turned into dialog. They tend to use subscription models.  People have speculated on the design of real dialog platforms, but I suspect much of the magic is in the same category of picking the perfect members of a team.  My friends tend to be those I can have interesting dialogs with - those who I can learn from.  i only hope our conversations are half as useful to them.

 

There's a special kind of dialog.  The face to face meeting I mentioned had little breadth in educational background.  We get things done, but I've found a lot of creativity seems to happen after talking to or working with someone who is smart, but in a very different field.  The process of learning from them seems to populate and connect parts of your mind that had never connected. Two weeks ago I had a long conversation - a dialog - with someone who is very different.  Over the next week new thoughts came almost daily and one gave me insight into something I've been thinking about for over a decade.  Lightning in a bottle dialogs.  Are there ways to support them?  I suspect the answer won't come from technology.

 

 

 

 

 

take it outside

a minipost

 

Other than the new graduate student, most of us have worked together for a few years.  This morning we carried our folding chairs across the large lawn struck by the novelty of seeing each other without glass, silicon and coordinated electrical signals getting in the way. It was our first face to face meeting since late February.

 

It would have happened earlier if we didn't believe the SARS-CoV-2 coronavirus couldn't be effectively carried by aerosols, but there's too much evidence to the contrary.  Aerosol clouds move and disperse quickly outdoors, so here we were with our face masks and some distance from each other.  Someone brought an easel with large sheets of paper and a few markers and we were off.  

 

A few things cropped up right away.   It gets hot sitting in the Sun for any length of time (you'd think we'd have more sense, but my type generally lacks it).  It was difficult hearing each other.  I can imagine a smartphone app that could take care of that - a local audio conference cloud.  (Gregg - this would be a good student project - I can think of several ways to do it).  One could also imagine iPad screen sharing, but I don't think it would work as well for our discussions - your mileage may vary.

 

We did manage to get a lot done - much more than the Zoom calls we've had.  There's a lot of "out of band" communication that takes place when you're face to face. 

 

I doubt that many would do this on a regular basis, but it raises an interesting point.  Indoors plus an aerosol transmission vector are a bad combination.  To make indoors work you need good fresh air exchange - perhaps a room volume every few minutes.  (Exactly how thoroughly and quickly isn't well-known yet.  This isn't anywhere as bad as measles for example.) Opening windows and doors using fans can do it.  The same with a properly balanced HVAC system .. but that can be difficult and expensive.  Most building systems recirculate air.  You can pass the air through a high-spec HEPA filter (note - HEPA is not a type of filter, but rather a standard).  Unfortunately they restrict airflow and it takes a lot of power to push air enough through.  I'd bet a fair amount of money most classrooms and offices aren't up to the task.

 

I jokingly suggested perfume, cigarette smoke, or incense smoke as a test to someone who studies aerosol physics.  They said it was a good idea.  You shouldn't be able to smell these kind of sources in a properly ventilated room unless you're very close.  Another test is CO₂ level.  A classroom full of people shouldn't register over 800ppm after an hour has gone by.  Building managers are often equipped to test CO₂ and volatile gas levels (you shouldn't be able to smell the carpet either). 

 

In many countries this won't be a big deal.  They've managed to get a handle on the situation with the ability to find and isolate hotspots.  How safe it is to have k-12 kids in schoolrooms is likely to be an experiment we'll see played out.  Colleges, restaurants and bars are probably a clearer call. Such decisions are well beyond my pay grade. 

 

 

rewiring your tardis

In the past few days three friends have been through a lot of stress.  Times like these make me think about where I've been and the paths I've taken.  I recognize too few people have had the freedom and privilege to make choices like I have.  At times like these I wonder about certain turning points that have been important - points that often seemed unimportant from others at the time.  More and more I'm drawn to thinking about events in space-time rather than in just time or space.

 

Studied closely neither time or space hold up on their own.  They seem to, but it's just an illusion that comes from the fact we move around on the Earth at tiny fractions of the speed of light. Space-time, with it’s four dimensions, gives a deeper way to sort out reality.

 

Since it's difficult thinking about anything with more than three dimensions it’s convenient to think of a three shadow of space-time with space as a two dimensioned plane and time running off at a right angle. If you think of the Earth’s orbit around the Sun as a 2d circle in space, we don’t come back to the spot every year in space-time.¹ Instead it's more like a helical slinky with about  four and a half billion equally spaced turns growing by another turn every year. Your birthdays are a long distance from each other.  A minute ago is a huge distance away too .. there's no way you can get back to it. 

 

Not going into detail, but the realization that paths are much more important than destinations was one that escaped me until I was about thirty.  Friendship, curiosity, serendipity ..  there are many things that turned out to be much more important to me than goals.  I like to think about these paths we take through space-time.  From a distance they look like spirals that ultimately might make eighty or ninety turns.  Zoom in on a short section and you realize there's a lot of jagged movement perpendicular to the flow of time. Other people and animals have their own jagged spirals sometimes coming very close or even touching yours.  Those times we're in the presence of each other.  At the scale of that expanding slinky we travel on around the Sun they're such rare events.

 

I've been having more intense dreams during the pandemic.  These ephemeral "realities" sometimes create alternate space-times that never could exist. Places and times that could never exist in the same real space-time.  During her final years my mother spend a lot of time in this place - even when she was awake.

 

For her last four years my mother had dementia.  It came in the form of small strokes.  She'd have one and then find herself with parts of her memory missing.  Between then and the next stroke her mind tried to make sense of the world.  How do you make reality square with what your mind can now connect to.  The brain does as much as it can and the mind now has a new reality to deal with.  

 

She never seemed to realize she had dementia and was usually very happy. Some memories - smell and music - seemed very robust.  But now her best friends might be someone from when she was fourteen and someone else from her forties.  One from Brigham City, Utah and the other from Great Falls, Montana.  She'd have conversations with them and sometimes complained that they didn't quite seem to see eye-to-eye.  The conversations must have been very real to her and overlapped directly into the world the rest of us perceived as real.  It was like watching someone walking along hearing half of their cellphone conversation.  

 

All of this was powerful to watch. Her mind, as it rewired itself, became a TARDIS of sorts that granted her a dream-like freedom from the rigid constraints of space-time.²  She was bringing some of those jagged microsections of the big helix of her life together.  And she seemed to love it.  It made me ask "who am I to judge the happiness of others."

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¹ it’s really an ellipse, but to make the argument a bit clearer I use a circle.

² On basic principles I won't define what a TARDIS is.