Fall is in the air B次元官网网址� officially.
The equinox arrives on Saturday, marking the start of the fall season for the Northern Hemisphere.
But what does that actually mean? HereB次元官网网址檚 what to know about how we split up the year using the EarthB次元官网网址檚 orbit.
WHAT IS THE EQUINOX?
As the Earth travels around the sun, it does so at an angle.
For most of the year, the EarthB次元官网网址檚 axis is tilted either toward or away from the sun. That means the sunB次元官网网址檚 warmth and light fall unequally on the northern and southern halves of the planet.
During the equinox, the EarthB次元官网网址檚 axis and its orbit line up so that both hemispheres get an equal amount of sunlight.
The word equinox comes from two Latin words meaning equal and night. ThatB次元官网网址檚 because on the equinox, day and night last almost the same amount of time B次元官网网址� though one may get a few extra minutes, depending on where you are on the planet.
The Northern HemisphereB次元官网网址檚 spring B次元官网网址� or vernal B次元官网网址� equinox can land between March 19 and 21, depending on the year. Its fall B次元官网网址� or autumnal B次元官网网址� equinox can land between Sept. 21 and 24.
WHAT IS THE SOLSTICE?
The solstices mark the times during the year when the Earth is seeing its strongest tilt toward or away from the sun. This means the hemispheres are getting very different amounts of sunlight B次元官网网址� and days and nights are at their most unequal.
During the Northern HemisphereB次元官网网址檚 summer solstice, the upper half of the earth is tilted in toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22.
Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun B次元官网网址� leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23.
METEOROLOGICAL VS ASTRONOMICAL SEASONS?
These are just two different ways to carve up the year.
Meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1.
Astronomical seasons depend on how the Earth moves around the sun.
Equinoxes, when the sun lands equally on both hemispheres, mark the start of spring and autumn. Solstices, when the Earth sees its strongest tilt toward or away from the sun, kick off summer and winter.
READ ALSO:
