If we have an extra day added every 4 years, then how come we are not noticing it?


If earth’s rotation is 365,25 days this means that the first year December 31st at 23:59 will look like an early afternoon; on year 2 it will look like noon and year 3 it will look like a morning (since we have 18 hours to spare).

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The Earth still _rotates) just the same around its axis making the day length, it is the _orbit_ around the sun making the year, we are correcting for. The earth does not complete the whole circle around the sun in 365 days, we need an extra day every 4 years to get it to roughly the right spot.

We officially “end the year” early, so that it is always at midnight.

After four years, the extra bits that we missed off have accumulated to be an entire day and we add that extra day on to the fourth year

Aahh earth still always takes 24 h to turn? The change you are looking for should be in seasons? And seasons aren’t exactly punctual like a clock. I think

That is not how it works.

A year is how long it takes the earth to orbit around the sun and a day is how long it takes the earth to turn once around its own axis in respect tot eh sun.

A year is not an whole number of days.

It takes the earth about 365 days, 5 hours, 48 minutes and 45 seconds to obit once around the sun.

IF we always had a calendar with 365 days. The missing 5 hours and 48 minutes each year would add up over time and things like the beginning of spring would move around bit by tiny bit.

To make sure that the season happen each year around the same time we have to add a day about every 4 years.

The system as we have it now is so that the earth is not quite in the same place each January 1st, but due to the way we dd a leap day (almost) every four years it evens out.

One year the earth may be a quarter of a degree away from making a full circle and the next year that adds up to half a degree and then your have a leap year and you are ahead half a degree and then ahead a quarter of a degree and things don’t ever quite line up but they are close enough that nobody notices it much.

Clocks describe the cycle of days, not years. At 11:59 pm on NYE (and every day of the year) it’s night time, because that’s what 11:59 pm means. A year and a day are two separate measurements of time describing two unrelated motions of the planet.

What is actually happening at year 1 at 11:59 pm on NYE is that the planet hasn’t *quite* finished it’s trip around the sun yet. That’s okay though. We give it a participation trophy and start a new calendar year anyway. It finishes at 6 am on 1/1, but we pretend it happened at midnight. Who can tell anyway? Well, after a few years, we’d actually start being able to tell, because seasons and star charts would stop lining up, so every 4 years we add an extra day, because otherwise, on year 4 at 11:59 pm on NYE the earth would have another whole day’s worth of travel to finish it’s trip.