I have already commented on the postponement of the American Solar Challenge due to COVID-19. The SASOL Solar Challenge in South Africa has also been postponed (see the current list of teams), as has the Albi Eco race.
The iLumen European Solar Challenge in Belgium is still expected to go ahead as planned, however (see the list of teams for that event).
One more “spot the difference” puzzle. The top is a copy of Children’s Games by Pieter Bruegel the Elder (1560). The bottom is the same thing with 21 edits of my own (including 8 outright additions, 7 outright removals, and 6 alterations of colour, shape, or number). The solution is here.
The American Solar Challenge, which was to have been held next July, has now been postponed until 2021, with a possible track-only event this September. Here, for historical reasons, is a list of the 34 teams (21 Challenger/SOV cars, 13 Cruiser/MOV cars, and no grandfathered cars) from 6 countries which were at one time registered for the race. Regular attendees SIUE, Florida, and UT were never registered, nor were WSC stalwarts Blue Sky. Teams are sorted in team number order and, as always, you can click the social media links, and click images to zoom (several photographs still reflect old cars). You can also check out the official ASC social media at 
(click on the icons).
University of Michigan 
Monohull challenger (Electrum) – their car name is the name of a gold/silver alloy famous in antiquity.
Previously, Michigan came 9th at WSC 13; came 4th at WSC 15; came 2nd at WSC 17; came 3rd at WSC 19; won ASC 14; won ASC 16; came 2nd at ASC 18; and won Abu Dhabi 15. Their team number (2) is a long-standing tradition.
Kentucky Symmetric challenger (Gato del Sol VI) – they will be back again, after doing well at FSGP 19.
Previously, Kentucky came 14th at FSGP 14; came 10th at FSGP 15; came 12th at ASC 16; came 7th at FSGP 17; and came 3rd at FSGP 19.
Massachusetts Institute of Technology Asymmetric challenger (new car: Nimbus) – they have said goodbye to Flux, and have built a new car.
Previously, MIT came 23rd at WSC 15; came 12th at FSGP 14; and came 5th at ASC 18.
Berkeley (CalSol) 
Four-seat cruiser (Tachyon) – they raced in Australia as number 66. Read about their Australian adventures here.
Previously, CalSol participated in the WSC 19 Cruiser class; came 15th at FSGP 14; came 7th at FSGP 15; came 9th at ASC 16; won FSGP 17; came 6th at ASC 18; and came 2nd in the FSGP 19 Cruiser class.
Vattenfall Solar Team (Delft) Asymmetric challenger (new car: Nuna Phoenix) – these are the champions formerly known as Nuon. Since their Nuna X was destroyed at WSC 19, they are building a new car specifically for ASC, incorporating features such as a metal roll cage (pictures shown are of their 2015 and 2017 cars, Nuna 8 and Nuna 9). They have also temporarily switched from their usual number 3.
Previously, Vattenfall won WSC 13; won WSC 15; won WSC 17; came 12th at WSC 19; won SASOL 14; won SASOL 16; and won SASOL 18.
Iowa State University (PrISUm) Four-seat cruiser (new car: Eliana) – the new car will have the suspension attached directly to a carbon fiber monocoque.
Previously, PrISUm participated in the WSC 17 Cruiser class; came 3rd at ASC 14; won FSGP 15; came 7th at ASC 16; and came 5th in the FSGP 18 Cruiser class.
Northwestern Symmetric challenger (SC7) – while a new SC8 is planned eventually, they will race the SC7 they sent to FSGP 19.
Previously, Northwestern came 16th at FSGP 16; came 12th at FSGP 17; and came 10th at FSGP 19.
Michigan State Two-seat cruiser (Aurora) – they are improving their car after having battery problems at FSGP 19.
Previously, Mich St came equal 15th at FSGP 17.
Stanford Solar Car Project Monohull challenger (Black Mamba) – they have a unique asymmetric bullet car with glass-free single junction GaAs solar panels, which they raced at WSC 19. Sadly, they had a serious battery fire during that event (video here). They are a late addition to the ASC field. They are very far behind on compulsory ASC documentation, suggesting that they are in some degree of trouble.
Previously, Stanford came 4th at WSC 13; came 6th at WSC 15; came 9th at WSC 17; and came 26th at WSC 19.
Illinois State Symmetric challenger (Mercury 6) – I believe that they are returning with their existing car.
Previously, Illinois St came equal 16th at FSGP 14; came 3rd at FSGP 15; came 11th at ASC 16; came 5th at FSGP 17; came 12th at FSGP 18; came 7th at FSGP 19; and came 13th at Abu Dhabi 15.
University of Illinois (Illini) Monohull challenger (new car: Brizo) – I understand that they are replacing the Argo that they raced before.
Previously, Illini participated in the WSC 17 Adventure class; came 7th at ASC 18; and came 4th at FSGP 19.
Waterloo (Midnight Sun) Four-seat cruiser (new car: MS XIV) – they are replacing their MS XII by a new four-seater, which they hope to unveil in April. They are proud of their design, which has a drag coefficient below 0.15. They decided not to have a car called MS XIII.
Previously, Waterloo came 4th in the ASC 18 Cruiser class and came 3rd in the FSGP 19 Cruiser class.
University of British Columbia Monohull challenger (new car: Daybreak) – they are building a new car. They attended FSGP 19 as guests.
Western Michigan (Sunseeker) Asymmetric challenger (new car) – they are building a new car to replace Farasi.
Previously, W Mich came 7th at ASC 14; came 14th at FSGP 17; came 9th at ASC 18; and came 5th at FSGP 19. Their team number (30) is a temporary replacement for their usual number (786 – the sequence of digits for S-U-N on old phones), to recognize the 30th anniversary of the team’s first race in 1990.
Principia Solar Car Team Asymmetric challenger (new car: Ra XI) – it is great to see this team returning, after skipping 2018.
Previously, Principia came 17th at WSC 15; participated at WSC 17; came 5th at ASC 14; came 5th at FSGP 15; came 5th at ASC 16; came 13th at FSGP 17; came 2nd at FSGP 19; and came 6th at Abu Dhabi 15.
University of Minnesota Solar Vehicle Project Four-seat cruiser (new car: Freya I) – they are America’s Cruiser class pioneers. They are building a new car, but raced their old car at WSC 19 (read their race report here).
Previously, Minnesota came 4th in the WSC 13 Cruiser class; came 5th in the WSC 15 Cruiser class; participated in the WSC 17 Cruiser class; came 5th in the WSC 19 Cruiser class; came 2nd at ASC 14; came equal 10th at ASC 16; and came equal 2nd in the ASC 18 Cruiser class. Their team number (35) is derived from the Interstate 35 highway.
Missouri S&T 
Asymmetric challenger (Independence) – they are returning with their most recent car, which failed scrutineering at ASC 18, and did not make FSGP 19.
Previously, Missouri S&T came 7th at FSGP 14; came 4th at FSGP 15; came 4th at ASC 16; and came 8th at FSGP 17. Their team number (42) is a Hitchhiker’s Guide to the Galaxy reference.
Georgia Tech Monohull challenger (Endurance) – they raced this car at FSGP 19. It is quite narrow, at 1.25 m.
Previously, Ga Tech came 13th at FSGP 15; came 17th at FSGP 16; came 6th at FSGP 17; came 8th at ASC 18; and came 9th at FSGP 19. Their team number (49) is taken from STS-49, the maiden flight of the space shuttle Endeavour (which was the name of their first car).
Poly Montreal (Esteban) Two-seat cruiser (new car: Esteban 10) – they are replacing the zippy little car they raced at ASC 18 and FSGP 19.
Previously, Esteban came 4th at ASC 14; came 2nd at FSGP 15; came equal 10th at ASC 16; came 3rd at FSGP 17; came 4th at ASC 18; and won FSGP 19. Their team number (55) is the year that Western Electric began to sell licenses for silicon PV technology.
University of Calgary Two-seat cruiser (Schulich Elysia) – they are the northernmost North American team. I understand that they are returning with the car that won the Cruiser class at FSGP 19. They are quite far behind on compulsory ASC documentation, suggesting that they are in some degree of trouble.
Previously, Calgary came 8th in the WSC 13 Cruiser class; came 9th at FSGP 15; and won the FSGP 19 Cruiser class.
Rutgers University Asymmetric challenger (Arctan) – they seem to have been given Stanford’s 2015 car for FSGP 19 (where they failed scrutineering). They are very far behind on compulsory ASC documentation, suggesting that they are in some degree of trouble.
Hypernova (George Mason) Cruiser (new team) – they planned on 3D printing the car body for their Cruiser, in spite of being advised against it. Progress on 3D printing was slow, with the first test prints only rolling off on 28 February. Berkeley (CalSol) gave them Gold Rush, a 3-wheel car from 2009. I’m not sure what they plan to do with it. They are also very far behind on compulsory ASC documentation, suggesting that they are in some degree of trouble. Their team number (77) is normally used by Toronto (Blue Sky).
New Jersey Institute of Technology (NJIT) Symmetric challenger (Eleos) – their car appears to be the one they began building for ASC 2018, based on the body moulds for CalSol’s Zephyr. It was still unfinished during FSGP 19.
Kaohsiung / Apollo Two-seat cruiser (new car: Apollo IX) – they have been building a new car for some time, but I haven’t seen a complete car yet.
Previously, Apollo came 6th in the WSC 13 Cruiser class; participated in the WSC 17 Cruiser class; and came 9th at Abu Dhabi 15.
Western University (Sunstang) Two-seat cruiser (new car: SunStang 2020) – they are building a new car for this event. The car uses Sunpower Maxeon Gen II monocrystalline silicon cells.
Previously, Sunstang came 14th at FSGP 15 and came equal 15th at FSGP 17.
North Carolina State University (SolarPack) Two-seat cruiser – they failed scrutineering at FSGP 19. They are returning with the same car, which they claim is “a vehicle no one has seen before,” and are feeling very positive. This video provides more details.
ETS Quebec (Eclipse) Asymmetric challenger (Éclipse X.1) – they raced in Australia as number 92, finishing 2nd among North American teams.
Previously, Eclipse came 18th at WSC 13; came 9th at WSC 19; came 10th at ASC 14; came 8th at ASC 16; came 4th at FSGP 17; and came 3rd at ASC 18.
Bridger Solar Team (Montana State University) Monohull challenger (new car) – KBZK Bozeman News has been telling their story. Their team number (406) is the telephone area code for Montana.
Southern California Solar Car Team Symmetric challenger (new car: Traveler 1) – this team has been fund-raising since 2015, but does not yet seem to have a car.
Grand Valley State Symmetric challenger (new team) – they appear to have gotten started by being given Poly Montreal’s Esteban 8. Their team number (616) is the telephone area code for Grand Rapids, Michigan.
PUT Solar Dynamics (Poznań University of Technology) Two-seat cruiser (new team) – they are making good progress on construction. This (Polish) video describes their project. They had originally hoped to race at WSC 19.
KU Solar Car Monohull challenger (new team with car: Astra) – they are raising funds for construction. The render they have posted shows a monohull design, 1.3 m wide. They completed their battery pack in March. However, they are quite far behind on compulsory ASC documentation, suggesting that they are in some degree of trouble. Their team number (785) is the telephone area code for northern Kansas.
Solar Car UPRM Asymmetric challenger (new car) – they will be returning with a whole new car – an asymmetric design this time.
Previously, UPRM came equal 16th at FSGP 14; came 12th at FSGP 15; came 11th at FSGP 17; and came 6th at FSGP 19. Their team number (787) is the main telephone area code for Puerto Rico.
Appalachian State University (Sunergy) Two-seat cruiser (ROSE) – they had been planning to race at WSC 19, but ran into logistics problems. They are making several improvements to the car for ASC 20.
Previously, AppState came 6th at ASC 16; came 2nd at FSGP 17; and came equal 2nd in the ASC 18 Cruiser class. Their team number (828) is the telephone area code for western North Carolina.
This page last updated 12:52 on 25 April 2020 AEST.
I have been playing around with “spot the difference” puzzles. This one is based on a photograph by Daderot, with a few edits of my own. More of these on my Instagram.
The chart above (click to zoom) shows registered deaths in the UK according to the ONS up to 10 April (note that during holiday periods, some deaths may be “carried over” to the next week). The year 2020 is on the way to passing 2018 as the worst year of recent times, with the fortnight to 10 April being particularly bad.
The difference between the red and black lines (highlighted in yellow) indicates deaths where COVID-19 was mentioned on the death certificate (this includes deaths “with” as well as “from” COVID-19, although other data suggests that in most cases COVID-19 would be the actual cause of death). A clear COVID-19 spike is visible.
The jump in the red line is also disturbing, however. The the red line shows deaths excluding deaths where COVID-19 was mentioned on the death certificate. The jump in the red line may indicate:
At present, I have no way of deciding which of those three options are the correct ones. Hopefully both COVID-19 and those other factors will pass soon (the IHME model suggests that COVID-19 deaths in the UK reached their peak on 21 April).
I should note that CNBC has also looked at this dataset, but they’ve compared this year against an average period that excludes 2018 and 2019. I don’t know why they did that.
A friend suggested this to me as a way of visualising COVID-19 risk for the United States. The red bars in the chart above show the expected death rates for different age groups over the whole pandemic period up to August 2020 (combining the projected total deaths from IHME with the age breakdown from CDC). For comparison, the blue bars show the expected deaths from other causes over an ordinary 9-day period (using data from CDC). For every age group, the risk of dying from COVID-19 during the pandemic is less than 9 days worth of ordinary risk, because 7,700 people die in the United States on an average day (of course, the COVID-19 risk would be somewhat higher without current social distancing measures).
For children and young people aged 0–24, the risk is less than 1 day worth of ordinary risk. This is clearer if we re-plot the chart on a logarithmic scale:
Update: I have updated the charts above to match the new IHME projections dated 16 April.
I have often tried to visualise the circle of fifths in a way that makes sense both musically and mathematically. Above (click to zoom) is my latest attempt.
There are 12 notes in an octave (7 white piano keys and 5 black piano keys), and the diagram shows these 12 piano keys wrapped into a circle. A fifth is a step of 7 semitones (7 piano keys, counting black ones, e.g. C→D♭→D→E♭→E→F→F♯→G). The coloured spiral in the chart shows the “circle of fifths” resulting from moving up a fifth 12 times (moving left to right, and hence moving anticlockwise).
The reason that this works is that 7 and 12 have no common factor – and therefore the first multiple of 7 that is also a multiple of 12 is 7 × 12. Therefore every time you move up a fifth you get a different note, returning to the starting note only when you have moved up 12 times. In the process, you have hit every other note exactly once.
This web site has been making COVID-19 projections for the US that seem to be tracking reality fairly well. They are predicting that 0.018% of the US will die. Comparing with this list, that is about 8% more than are normally killed during a year by ordinary influenza or pneumonia.
The apparent high death rate in other countries seems to be due to a combination of poor-quality health care and inflated statistics resulting from under-testing the population. In a few weeks, we will see how accurate the US projections are (the Wyoming predictions seem dubious to me).
Below, from the same projections, are predicted ICU bed demands in excess of state capacity (click to zoom). It can be seen that there is a particular problem in the northeast.
Update: I have updated the charts to match the new IHME projections dated 16 April, and added expected death rates for each state (below, click to zoom):
The expected death rates for each state seem to have no relationship to the number of control interventions implemented by state governments. Clearly other factors are decisive:
Scientific Gems 