How many minutes are in a full day?

1,440 - twenty-four hours of sixty minutes. The sixties are inherited from Babylon, which counted in base sixty, and it has survived four thousand years because 60 divides neatly by 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30. Splitting an hour into thirds is easy; splitting a hundred is not.

The day is not exactly 1,440 minutes long, which is why leap seconds exist. Tidal friction from the Moon is very gradually slowing the Earth's rotation, and the rotation also wobbles unpredictably as mass shifts in the core and the oceans. Since 1972, 27 extra seconds have been inserted into official time to keep clocks matched to the planet.

They are being abolished. Leap seconds cause real trouble for computer systems, which do not expect a minute with 61 seconds in it - one in 2012 took down a number of large websites at once. In 2022 the international body responsible voted to stop adding them by 2035 and let the discrepancy accumulate instead. The Earth is losing an argument with the software.