From the combo of sol (sun) and sistere (cause to stand or stop) the solstice marks the highest or lowest points of the sun’s path in the sky each year.

In Summer, for instance, the sun’s arc in the sky stops going higher each day — at its highest point with the longest day— pausing before descending through the Autumn equinox of equal day and night — where the sun rises and sets exactly East and West — to its lowest point and shortest day at the Winter solstice. At that point — when you’re getting up in the dark and returning home in the dark — it will stop its descent and slowly climb higher each day once again towards the Summer solstice.

Solstice

It’s pretty hard to get to grips with the scale of the solar system when Venus, the closest planet, feels really far already. But we’re practically squished together compared to Uranus and Neptune — they are a really, really, really long way away.

James O'Donoghue has made some brilliant videos about the solar system that explain this and more.

Solar system planets — distances to scale

On the equinox there is nearly exactly 12 hours of daylight and night — the day and night are perfectly balanced. On these days the sun rises almost due East and sets due West.The Spring equinox and Fall equinox are the transition between the seasons of Winter to Spring or Summer to Fall, depending on if your days are getting longer or shorter. The other seasons transition at the solstices.

Technically, the equinox is the instant “the plane of Earth’s equator passes through the center of the Sun.” (wikipedia) This usually happens around the 20 March and 23 September.

The equinox exists due to the tilt of the Earth. See Seasons

Here in the Northern hemisphere we just transitioned to Spring and it’s well appreciated.

Sketchplanations tagged with sun