quarantine 'em

It spins too slowly, it spins at irregular rates, it is constantly slowing down, and it can never be wound

Vibrating caesium atoms are much more reliable, and that's where we derive atomic time from

Unfortunately, for the purposes of civil timekeeping, the rotation of the Earth is all that matters, and nobody cares about caesium atoms

UTC is the compromise which gives us atomically accurate civil time while also actually tracking the solar day properly

Be honest, you probably don't need to care about leap seconds

Anyway, the extra second at the end of 2016 is likely to be one of 2016's better seconds

Note: the leap second happens at 23:59:60 UTC, no matter where you are. In the US, that's mid-to-early evening

In Australia, the leap second will be something like 10:59:60am on 1 January 2017