The autumn equinox is right here. What does that imply?

NEW YORK (AP) — Fall is within the air — formally.

The equinox arrives on Saturday, marking the beginning of the autumn season for the Northern Hemisphere.

However what does that truly imply? Right here’s what to find out about how we cut up up the 12 months utilizing the Earth’s orbit.

WHAT IS THE EQUINOX?

Because the Earth travels across the solar, it does so at an angle.

For a lot of the 12 months, the Earth’s axis is tilted both towards or away from the solar. Meaning the solar’s light and heat fall unequally on the northern and southern halves of the planet.

Through the equinox, the Earth’s axis and its orbit line up in order that each hemispheres get an equal quantity of daylight.

The phrase equinox comes from two Latin phrases that means equal and evening. That’s as a result of on the equinox, day and evening final nearly the identical period of time — although one might get just a few additional minutes, relying on the place you’re on the planet.

The Northern Hemisphere’s spring — or vernal — equinox can land between March 19 and 21, relying on the 12 months. Its fall – or autumnal — equinox can land between Sept. 21 and 24.

WHAT IS THE SOLSTICE?

The solstices mark the occasions in the course of the 12 months when the Earth is seeing its strongest tilt towards or away from the solar. This implies the hemispheres are getting very totally different quantities of daylight — and days and nights are at their most unequal.

Through the Northern Hemisphere’s summer time solstice, the higher half of the earth is tilted in towards the solar, creating the longest day and shortest evening of the 12 months. This solstice falls between June 20 and 22.

In the meantime, on the winter solstice, the Northern Hemisphere is leaning away from the solar — resulting in the shortest day and longest evening of the 12 months. The winter solstice falls between December 20 and 23.

WHAT’S THE DIFFERENCE BETWEEN METEOROLOGICAL AND ASTRONOMICAL SEASONS?

These are simply two alternative ways to carve up the 12 months.

Meteorological seasons are outlined by the climate. They break down the 12 months into three-month seasons primarily based on annual temperature cycles. By that calendar, spring begins on March 1, summer time on June 1, fall on Sept. 1 and winter on Dec. 1.

Astronomical seasons rely upon how the Earth strikes across the solar.

Equinoxes, when the solar lands equally on each hemispheres, mark the beginning of spring and autumn. Solstices, when the Earth sees its strongest tilt towards or away from the solar, kick off summer time and winter.

The Related Press Well being and Science Division receives help from the Howard Hughes Medical Institute’s Science and Academic Media Group. The AP is solely liable for all content material.