#afactaday2025

#1676: after the eruption of Ksudach volcano, Kamchatka, in 1907, much of the surroundings were caked in "air-fall" pumice. some areas up to several metres deep had all life and water completely wiped, whereas some were just a few cm deep. this made it a perfect case study in succession (ecology, not the tv show). with a metre of pumice, lichen came back first, forming a "desert", followed by "pioneer herbs". in 10-30cm deep pumice, secondary succession was most prominent, whereas primary succession was moreso in 70-100cm. which makes sense. in the sweet inbetween spot is a "complex mosaic" of all sorts of plants coming back and coming for the first time. a 1994 study on this eruption recreated detailed maps of the area before and shortly after the 1907 eruption. they're ugly and old so i won't bother embedding, but they're fascinating to compare. there are a lot more different types of land many years after the eruption compared to before, even if each individual type is much less diverse. of course the lakes and rivers were filled in but then they found their way back very quickly to exactly the same size and shape, just in slightly different places. it's absolutely fascinating. the same study estimates that it'll take 2000 years for the area to "recover" completely to a climax community.

#1650: the ant Temnothorax albipennis sometimes needs to move its nest, and they use a magnificent process to choose a new site. they send out scouts who find possible sites, usually crevices. then they use tandem running to bring more ants to the new nest site, except they wait a little bit each time. the wait time is inversely proportional to how good the new nest site is - so if the new site is perfect they'll recruit ants immediately and if it's only just passable then they'll wait a while. ofc it also takes time to travel so further-away nests are also less favourable, which makes sense. eventually one of the nests will reach a critical threshold (measured by how often ants interact with one another) and when this happens, that means a high enough proportion of the colony has favoured a certain site, and the new nest has been chosen. it's insanely clever and efficient and gets the best result, yet no single ant orchestrates it. honey bees use similar processes i think, except with more waggling

#1583: the Fujita scale for assessing the intensity of a tornado was invented in 1971, but it wasn't really properly grounded in physics - all the numbers were more or less wild guesses, and you based on consensus. they upgraded the system to the Enhanced Fujita scale, which runs very similarly, but more standardised: there are a list of 26-odd "Damage Indicators" (Canada uses 31) which are basically types of structures (bungalow, shed, fence, stuff like that) and the windspeeds at which they fall over. the main difference between the two scales is that now all these structures are standardised: a wooden fence is made of panels with posts sunk into concrete post holes in the ground, for example. measuring the amount of roof lost on a heritage churche, for example, will point towards particular wind speeds to help categorise a tornado. the first tornado to get an EF5 on the new system was the Greensburg tornado in 2007.

Alice in Wonderland was written with a target audience of three people, the Liddells, and there whole book is filled with easter eggs and in-jokes that only these three children in specific were expected to understand. perhaps this one is similar.

#1488: the Dickin Medal, instituted by Maria Dickin, an animal welfare pioneer, honours animals for displaying valour in battle, as an equivalent of the Victoria Cross. it's been given to 54 different animals, over 32 of which were pigeons, i guess making them the bravest animal. to be honest i'm not sure whether they had much of a say in the matter. the other recipients are mostly dogs, but there were also five horses (one of which was called Sergeant Reckless who served in the Korean War and ate $30 of poker chips) and a cat (called Simon, who "disposed of many rats despite shrapnel injuries" and ultimately died of an infection. after killing a "particularly viscious rat known as Mao Tse-Tung" he was promoted to Able Seacat, and received so much fan mail that a Lieutenant was designated his secretary.)

#1473: some economists use the Big Mac Index (BMI) as a measure of the purchasing power of a currency. it can often disagree with the World Bank's purchasing-power parity (PPP) estimates by up to a factor of two, which are used on the global exchange market. sometimes, even though a currency is worth less, it can stretch more in its home country; instead, this patty-power parity is used as a better measure of how much some currency will actually get you. the US's economy overtook China's in the 1880s and is supposedly about 1.5 times as large (2019), but that's based on PPP exchange rates; if you instead spend China's entire GDP on 4.6 trillion Big Macs and then take them to the US and sell them, you'll find that China's economy is "larger" and has been since 2014.

anyhoosles! thank you so much if you're (somehow) still reading - i truly do thank anyone who's sent me a thought or comment or even a reaction haha! all the thoughts i've been given on the future of FOTD, and fotd2026, have been greatly appreciated, and of course the table is still wide open to future developments. i think i'll go quite a way off the beaten path this year - it's clear that consistency hasn't worked out for me this year, but we'll see where that takes us. thank you all, and all the best!!

#1825: some insects can be pretty susceptible to temperature so they put a lot of effort into thermoregulation. wood ants, for example, build nests out of pine needles which heat up in the sun very easily but also insulate well to keep the nest at a constant temperature through the night. in the tropics, lots of ants' nests go really deep underground where the dampness keeps it cool and the ground stays a constant temperature. some ants move their larvae and eggs up and down between chambers during the day and night as it warms up and cools down, so the brood is always at just the right temperature!