On the Himawari satellite

Adapted from this twitter thread, 13 November 2019

I had an "Ohhhh" moment just now when I realised why the Japanese weather satellites are called "Himawari". The Himawari series are weather satellites belonging to the Japanese Meteorological Agency. They provide their satellite imagery to meteorological agencies in other countries. It has a lot of very lovely imagery of the Asia-Pacific region, although unfortunately today I was mostly admiring the way it captured the Australian Bushfires.

The area of the smoke over the Pacific Ocean is now larger than #Australia 🇦🇺. Image source: Japanese Himawari-8 #satellite, 12 Nov 2019 at 20:10 UTC time via @CIRA_CSU. #bushfires #NSWfires pic.twitter.com/UgUmfZXIE2

— Antti Lipponen (@anttilip) November 12, 2019

Himawari means "sunflower", which breaks down into 日(『hi』sun) and 回り(『mawari』to spin). The name refers to the way the flower turns to track the sun across the sky.

But 日 can also be used to mean day. Since the Himawari satellites are geostationary, it follows the earth's orbit i.e. it does an orbit every day. And since it orbits the earth, which in turn orbits the sun, it follows the sun too.

An interesting addendum is that himawari actually has several kanji "spellings". The main kanji for it is 向日葵, which is a loanword from Chinese. In Japanese, those characters would not normally be read as "himawari" i.e. it's an irregular word, where the characters don't match up with the pronunciation at all.

The kanji I gave earlier – 日回り– is the literal rendering of the Japanese word "himawari". It's an alternate kanji for it, but not the main one. So 向日葵 takes the meaning of the Chinese written characters, translates it to Japanese, then slaps that reading back onto the characters.