Get the latest tech news
What is a second?
A second is now defined in terms of periods of radiation from a cesium atom. Why was this necessary? Why cesium? What the particular number of periods?
The previous post looked into the common definition of Unix time as “the number of seconds since January 1, 1970 GMT” and why it’s not exactly true. Clearly the number was chosen for backward compatibility with the historical definition of a second, but that only approximately settles the question. Here “tropical year” means the time it took earth to orbit the sun from the perspective of the “fixed stars,” i.e. from a vantage point so far away that it doesn’t matter exactly how far away it is.
Or read this on Hacker News