As the planet’s mass becomes more oblate, or flatter, it spins more slowly and thus an Earth day gets longer. No one expected to ever need a negative leap second, so it has never been tested. While some experts believe a negative leap second is inevitable, we will eventually abandon leap seconds entirely. In 2022, the General Conference on Weights and Measures voted to end the leap second from 2035 for 100 years. Perhaps this should hasten the leap second’s demise.
