A new decade?
The job of an ontologist is to define concepts. And since I see some posts commenting on whether a decade is closing and a new decade is starting tonight, here's my private, but entirely official position.
A decade is a consecutive timespan of ten years, and therefore at every given point a new decade starts and one ends. But that's a trivial answer to the question and not very useful.
There are two ways to count calendar decades, and both are arbitrary and rely on retconning, I mean, they really on redefining the past. Therefore there is no right or wrong.
Method one is by using the proleptic Gregorian calendar, and starting with the year 1 and ending with the year 10, and calling that the first decade. If you keep counting, then the twohundredandthird decade will start on January 1st 2021, and we are currently firmly in the twohundredandsecond decade, and will stay there for another year.
Method two is based on the fact that for a millennium now and for many years to come there's a time period that conveniently lasts a decade where the years start with the same three digits. That is, the years starting with 202, which are called the 2020s, the ones with 199 which are called the 1990s (or sometimes just the 90s), etc. For centuries now we can find support for these kind of decades being widely used. According to this method, tonight marks a new decade.
So whether you are celebrating a new year tonight or not (because there are many other calendars out there too), or a new decade or not, I wish you wonderful 2020s!
SWAT4HCLS trip report