https://en.wikipedia.org/wiki/Sidereal_year

In the time it takes the earth to revolve around the sun, the earth rotates on its axis 365.256363004 times. (simply put, 1 year = 365.256363004 days)

If that number was exactly 365.2500000, then we could simply have a leap day (feb 29) exactly every 4 years to account for the 0.25

However, since the number is actually greater than 365.25, wouldn't we need to have even more leap days? 0.25/0.006363004 = roughly 40. So, the way it seems to me, we should need to have an extra leap day for every 40 (Instead of having 40 leap days in 160 years, we should need to have 41)

But our current system is actually the opposite. Right now, we only have 97 leap days every 400 years (fewer than 1 every 4 years). https://www.timeanddate.com/date/leapyear.html#rules

Can anyone help me find the source of my confusion? It really seems like we need to be having leap days more than once every 4 years. But we are actually having it less than that on average.

This post was edited by Kayeto on May 16 2020 10:14pm

Start at 2 minutes to avoid introduction

2:14: "lengthening the calendar by 1 day every 4 years is slightly too much"

That seems false to me. It's not too much, it's too little. The true number of days in a year (365.256363004) is greater than 365.25. That's where I'm confused.

It seems like we need more leap days to adjust for the every 0.006363004 excess. We don't need fewer.

This post was edited by Kayeto on May 16 2020 11:51pm

When I google it brings up nasa.gov and sources 365.2422 days. Where did you source the number you are using?

the very first line of my first post

was i just blind and misread that whole wiki?

This post was edited by Kayeto on May 16 2020 11:52pm

"The sidereal year differs from the tropical year, "the period of time required for the ecliptic longitude of the Sun to increase 360 degrees",[2] due to the precession of the equinoxes. The sidereal year is 20 min 24.5 s longer than the mean tropical year at J2000.0 (365.242 190 402 ephemeris days).[1]"

I guess that's where my confusion is then because none of that makes sense to me. Can you ELI5 for me what effect the procession of the equinox's has on the situation and why the tropical year is the right number but the sidereal year is the wrong one?

Is it that ancient astronomers got "tricked" into relying on the sidereal year because they were using the rest of the stars as a framework, but they didn't realize that those other stars were also moving in their own ways?

This post was edited by Kayeto on May 16 2020 11:59pm

Ancient astronomers could not see stars changing positions. They only change relative position with the Earth over thousands of years, and the kind of record-keeping that would be required to understand that just didn't exist until the industrial era.

Neither is "right", but if you want your calendar to stay in line with seasons then you use the tropical year.

The source of the confusion is Satan.
Satan created the lie of a spinning ball earth.
A sphere or ball has no borders or walls, so this lie was meant to suppress humans natural curiosity to explore.
What would happen if people went to Antarctica and found the edge of earth and the solid firmament that encloses our world?
That was taken care of almost 70 years ago with the Antarctic Treaty that prohibits all exploration.
Another clue that reveals the lie about a spinning ball earth is, ask yourself why can you see the same star constellations in the sky at night, each and every night?
How is that possible if the ball earth is hurtling through space (being invisibly pulled by a giant sun) while spinning at the same time, but you see the same stars every night??????

Procession of the equinoxes only affects the seasons, not the years.