Today the summer solstice — the longest day of the year in the Northern Hemisphere — will begin, and it will be the earliest solstice in 228 years.
This means that the solstice is the opposite in the Southern Hemisphere — the June solstice is the shortest day of the year and marks the winter solstice in the south. The calendar divides one year into 365 days. However, Earth's actual full orbital time around the sun is 365 days, 5 hours, 48 minutes and 45 seconds — which we account for by adding a leap year every four years to round the calendar up. But this creates its own problem: four times 5 hours, 48 minutes and 45 seconds is 23 hours and 15 minutes, meaning it's 45 minutes short of a full day.