If Earth were to shift to even longer days, we may need to incorporate a “negative leap second”—this would be unprecedented, and may break the internet.

~ Matt King and Christopher Watson from, https://phys.org/news/2022-08-length-earth-days-mysteriously-scientists.html

The use of the phrase “may break the internet” made me smile. It’s not irony, and it’s serious. I do not want to think about what would happen if they inserted a negative leap second; The forward sort are bad enough, and don’t get me started on Daylight Savings Time. I digress.

This is a refreshingly clear, popular-science level article that covers the myriad reasons there is such variability in the exact amount of time it takes our magic marble to whirl precisely once around its axis. The very first thing most people never think of is how do we even precisely decide what “one rotation” is. (Hint: Astronomy.)

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