#when winter changes to spring it completes a full axial rotation cycle for the earth

[obey-the-milkman]

guys. its march. we made it.

🌞 daytime will be just as long as nighttime 🌙 it will be spring 🌱 flowers will bloom 🌸 and the winter depression is shedding

also i learned some cool stuff and i infodumped about it in the tags if you know about it i would love to know if i came to the correct conclusions

[megacircuit9universe]

A Quasi Religious Orbital Completion Time to All!

THU DEC 26 2019

Though our orbit around the Sun is not circular, but elliptical, there are still four keenly discernible moments in that orbit, which divide it cleanly at right angles, into four quarters.

This is thanks to the fact that we not only orbit around the Sun, but we also spin on our axis.  That spin, means we have angular momentum, and that angular momentum means that our axis wants to stay in a fixed orientation with respect, not to the Sun, but to the universe.

What does that mean?... well, the North Pole always points to a distant star known as Polaris... no matter where we are in our annual circuit around the Sun.

Not that there’s anything special or magical about Polaris... it’s just an accident that a star, 430 light years away, happens to be more or less at the same spot where our apparently rotating sky appears to be anchored.

Now, the sky is not actually rotating, but, if you sit outside for a whole night, and pay attention to how all those stars rise in the east.... circle over... and set in the west... it will appear that the sky is indeed a sphere that rotates around us.

And if you are in the Northern Hemisphere, then you will also notice that Polaris doesn’t rise or set.  It just sits in the same spot all night... and all year.  The constellations nearest to Polaris, such as the Big Dipper, also don’t really rise or set.... they just travel in a small circle around Polaris.

Further away from Polaris, the constellations start to get blocked by the horizon... rising and setting in ever longer arcs*.

All of the constellations, and all the stars that compose them, are all fixed, relative to one another... like a bunch of dots painted on the inside of an enormous black sphere, with glow-in-the-dark paint.

They are the unchanging background of our night sky.

This background only appears to rotate, because our planet itself is rotating... but the position of Polaris in the sky never moves... no matter where we are in our annual journey around the Sun... because of the Law of Conservation of Angular Momentum... which keeps our axis in the same orientation with respect to the universe... and not with respect to the Sun**.

Now, with respect to the plane around which we orbit the Sun (the plane of the Sun’s equator) this rotational axis of ours is not perpendicular, but instead, tilted by about twenty-three degrees.

This is why our North Pole MUST, at one point in our orbit, point 23 degrees away from the sun, while at the exact opposite point in our orbit... it MUST point 23 degrees toward the sun.

It must do this, because it must always point to Polaris, thanks to angular momentum.

But this means that there are two other points... where our axis is neither pointing away from, or toward the sun, but is exactly side-on to the sun... in other words... still tilted at 23 degrees as always, our axis is now side-on, such that it’s tilt is neither away, nor toward it... and thus all surfaces of the Earth, from pole to pole, get, for one rotation (or one day) exactly equal illumination.

Everybody has twelve hours of daylight and twelve hours of night... from the North Pole to the South Pole, and the Equator too.

Those two points are known as the vernal (spring) and autumnal (fall) equinoxes.

The former two points, are known as the solstices, with one solstice having the longest night/shortest day of the year, and the other having the shortest night/longest day of the year...  and whichever solstice it is, for the northern hemisphere... will be the opposite for the southern hemisphere.

Northern winter is southern summer, and vise versa.

So... as it happens, we humans evolved at a time on the planet where the forever drifting continents which sit atop forever moving tectonic plates***, happened to be situated such that we had a lot more land mass around the northern hemisphere... which inevitably lead to our current cultural bias in which the beginning and end of a year takes place around the northern winter solstice.

If you’re starting without a calendar, and only have those four cardinal points in the orbit to go by, then you’re gonna pick a solstice, rather than an equinox, to be the start/end point of the year... because the equinoxes are identical to one another, whereas the solstices are distinct opposites.

That given, you’re gonna want to hold your big celebration on the winter solstice, rather than the summer solstice... because winter is a bitch.  It’s long and dark and cold.  All the plants are dead, and most of the animals are gone... because of migration, hibernation, etc.

You and your society need the psychological boost of a new year celebration on that longest night of the year... to keep hope alive.  Throwing a party and having a feast on that day is a big middle finger to the otherwise looming despair of winter.  It says that we know the days will get longer from here, and therefore that things will get better eventually... and also that we’ve stored up enough food and fuel, that we can survive this even after a huge feast.  

Fuck you, Winter!  We’ve made it through another year, and we will be just fine!

And back then there was one class of plant that didn’t die in the winter... the evergreens... the pine trees.  And there was one class of big game animal that didn’t go away... the deer.  Moose, reindeer, regular deer... which explains why both are still so central to the modern celebration.

Modern Christmas and New Year are simply the start and end of a week long solstice celebration full of gift giving, feasting, drinking, and partying, while the cares of daily life are ignored as much as possible.

Places of business go down to skeleton crews, closing completely when possible. The news cycle grinds to a halt. Social media dies down. We need this whole week to be as big a blur of heady escapism as possible... so that when we get back to our senses, we find ourselves one week to the good, in terms of the coming slog, that will be January and February.

In Modern times, this week long celebration doesn’t even begin until four days after the actual winter solstice... in order to give us that slight extra edge on the lengthening daylight, when January begins.

Not that eleven or twelve days makes any noticeable difference in the actual length of daylight... and not that daylight means much when the worst of winter, in terms of snow and cold, doesn’t hit until late January, early February... but... eleven or twelve days is the max length we can get away with for shutting down civilization to get drunk and feast... so... we do the best that we can with it.

We try to make it as merry, and happy as possible, for as many people as can possibly participate, young and old, rich and poor... and we do our best to erase the slate and start fresh for another lap around the Sun... even if the timing of it doesn’t make a whole lot of sense to anybody living in Australia, Africa, and South America.

If they don’t like New Year coming in the middle of their summer, then they can just suck it!  Because they don’t have a pole star!  Get a pole star, losers!.. or stop complaining!

Okay, well, that said, I’d like to take this opportunity in the middle of this special week, to wish everybody a very quasi religious, Orbital Completion Time.

*Certain constellations near or below the celestial equator are only visible to people in the northern hemisphere at certain times of year.  This is not because they drift.  All constellations visible from your latitude rise and set every single day.  But many will rise and set during daylight hours, and therefore not be visible, when Earth is on one side of its orbit. 

** The Moon does serve to stabilize the Earth’s axial tilt, which would wobble a lot more due to the gravitational influence of nearby planets, despite angular momentum wanting to resist any change.  The Moon, which itself trades angular momentum with the Earth in their gravitational dance, acts as a balancing pole, which considerably tamps down any influence from our solar system neighbors. 

***The shifting of tectonic plates, and subsequent movement of the continents is a surface phenomenon that has nothing to do with the Earth’s spin, or it’s orbit. It’s a process that takes hundreds of millions of years to be noticed, and is driven only by heat exchange with the much hotter layers beneath the crust, going down to the core.