The Seasons

It’s solstice time in a few days, so here is an infographic on the seasons (click for hi-res image):

Infographic constructed using R (with DescTools::DrawCircle, rasterImage, layout, and the suncalc package for day length calculation). Images used are a diagram by “Colivine,” paintings by Arthur Streeton and Joseph Farquharson, and two photographs of my own.


The constellation Scorpius

Winter is here (in the Southern Hemisphere, at least), and the constellation Scorpius always heralds the southern winter’s icy sting. The image below is based on a vintage astronomical illustration, but I have corrected the star positions of the major stars and indicated their apparent magnitude (brightness) and approximate colour (based on spectral class). It is interesting to compare the image with this quality photograph.

Generations of astronomers have memorised the O–B–A–F–G–K–M stellar classification system developed by Annie Jump Cannon with the mnemonic “Oh, Be A Fine Girl/Guy/Gal/Gentleman, Kiss Me.” Scorpius does not contain any bright O-class stars, but it is easy to see stars ranging from the hot blue-white B class to the cooler orange-red M class (stars which are only “red hot”).

The most obvious star in Scorpius is the enormous red supergiant Antares, which has that name because it is easily confused with the planet Mars (Ares). It is also known as “Cor Scorpii” (the heart of the scorpion). It is easy to recognise the curved tail as well, with the stingers Shaula and Lesath at its tip. It is less obvious which stars are the scorpion’s claws – the artist here has drawn the left claw extended so as to reach the dim white star Psi Scorpii. Other artists draw the scorpion facing more to the right, with the line of blue-white stars being the claws.

Infographic constructed using R (with lm to map true sky coordinates to image coordinates, rasterImage for the background, and the showtext package for fonts).

Eureka! – a book review

Eureka!: The Birth of Science by Andrew Gregory

I recently read Eureka!: The Birth of Science by Andrew Gregory. The book deals with a topic that has long fascinated me – the birth of science. In a previous post I argued that this took place in the 12th century, the age of cathedrals. Gregory takes the view that it happened with the ancient Greeks, and sees Aristotle and Archimedes as among science’s pioneers. He gives a brief defence of this thesis, and provides a quick summary of Greek scientific thought.

Aristotle and Archimedes

I found this book rather short for the subject (177 pages, including bibliography), was disappointed at the lack of endnotes, and found some annoying errors (the Greeks did not consider the universe small, for example – Archimedes took it to be 2 light-years across). But the big unanswered question is: what went wrong? Gregory includes a list of key people at the back of the book, and if you turn that list into a bar chart, you can see that Greek science basically fell off a cliff around 200 BC.

In a brief two-page section towards the end, Gregory suggests that Christianity was somehow responsible for the decline of Greek science, but that simply makes no sense. Was it instead Roman conquest, beginning around 280 BC? Was it the growing separation of aristocratic philosophy from plebeian technology? Was it the replacement of original science by encyclopaedic systematisation (such as that of Pliny)? It would have been nice to have those questions answered.

Goodreads gives this book 3.4 stars; I was rather less enthusiastic.

Eureka!: The Birth of Science by Andrew Gregory: 2 stars

Bridges, gender, and Benjamin Lee Whorf

I’ve long been fascinated by the Sapir-Whorf hypothesis – the idea that the structure of language determines (or at least influences) the way that you think. I first read Whorf’s book several decades ago.

A friend recently pointed me at this TED talk by Lera Boroditsky. After years of being sneered at, it seems that Whorf is back in fashion.

And there’s certainly something to Whorf’s ideas. For example, there is solid evidence that the way that you name colours influences the way that you see them (slightly, anyway). There is some exaggeration in the TED talk, though. Australian aboriginal speakers of Kuuk Thaayorre have a unique way of describing directions (in absolute, rather than relative terms, e.g. “there is an ant on your northern leg”). They also navigate well across their tribal lands. But is there a causal relationship? Do aboriginal people with this linguistic feature navigate better than those without it? No, they don’t.

Even stranger is the idea that Spanish speakers, for whom a bridge is masculine (el puente), are less likely to describe a bridge as “beautiful,” and more likely to describe it as “strong,” than German speakers, for whom a bridge is feminine (die Brücke). There really are way too many confounding factors there – people who speak different languages differ in other ways too. So I thought I’d try a quick-and-dirty experiment of my own.

For a set of 17 languages, I counted Google hits for the phrases “beautiful bridge” (e.g. French: beau pont, German: schöne Brücke) and “strong bridge” (e.g. Greek: ισχυρή γέφυρα, Dutch: sterke brug), divided one set of numbers by the other, and took the logarithms of those ratios. The chart below summarises the results. Languages in pink have a feminine bridge, languages in blue have a masculine bridge, and languages in grey have a bridge which is neither (for example, English has no gender, while Dutch and Swedish have merged masculine and feminine into a “common” gender).

The mean values there are 0.95, 1.14, and 1.60, where positive numbers mean more hits with “beautiful bridge” (i.e. the trend runs the opposite way from the prediction), but none of the differences are statistically significant (p > 0.4). Gender does not seem to influence perceptions of bridges.

Interestingly, if we exclude the international languages English and Spanish, there is actually a statistically significant (but weak) correlation with GDP of the relevant nation (p = 0.029, r = 0.58). On the whole, poorer countries are more likely to describe a bridge as “strong,” and wealthier countries as “beautiful.” That makes sense, if you think about it (although Iceland is an exception to this pattern).

How about you? Is the bridge beautiful, or strong?

Nature journals

Having said something about phenology wheels, I thought that I should mention nature journals too. Some years ago, I blogged about the professional aspects of this, but nature journals are a powerful educational tool, because of the way that they focus observational attention. John Muir Laws has good advice on getting started, including “Do not focus on trying to make pretty pictures. That just leads to journal block. Open your journal with the intention of discovering something new. Use the process to help you slow down and look more carefully.

Mother and child nature journaling examples from Nature Study Australia Instagram and website

The very useful Nature Study Australia website also has good advice and several examples, as well as other nature study resources for Australians. Artist Paula Peeters, aiming more at adults, runs nature journaling workshops around Australia, and offers an introductory book for sale or free download.

Nature journaling example from Paula Peeters, who runs workshops around Australia

Nature journals need not only contain pictures and text: a spiral-bound sketchbook will easily accomodate flat objects such as leaves, pressed flowers, feathers, and sun prints. Drawings are an essential aspect, however.

The CNPS curriculum

The California Native Plant Society offers a superb nature journaling curriculum for free download. It includes the observational prompts “I notice… I wonder… It reminds me of…” It advises parents and teachers not to say things like “that is really pretty” or “what a good drawing,” but instead to say things like “Oh, you found a spider on top of the flower! Great observation.” It also provides excellent practical advice on drawing, poetry, and other activities.

With so many excellent guides to nature journalling, why not get started on your own?

A drawing of mine (from quite some time ago)

Midwestern Solar Challenge

On June 3, two of the top Cruiser-class solar cars held a Midwestern Solar Challenge, racing south from St Paul, MN to Ames, IA. The teams were:

Race news


Here is my (totally informal) scoring of the race (see the chart below):

  • Person-kilometres is the race distance times the average number of people carried (which I believe was 4 for PrISUm and 2 for UMNSVP). The first coloured bar shows this, scaled so that 100% is the highest value.
  • Energy input is the number of charges (1, in this case) times battery size. The second coloured bar shows this, scaled so that 100% is the highest value (this bar points downward, because smaller is better).
  • The third coloured bar shows the ratio of these numbers, scaled so that 80% is the highest ratio.
  • We add on (in grey) the practicality scores (I’m estimating 9 for PrISUm and 7 for UMNSVP), scaled so that 20% is the highest practicality.
  • This gives final scores of 100 for PrISUm and 82 for UMNSVP. Congratulations, PrISUm!
  • But will PrISUm still have the advantage when it needs to carry passengers uphill?