Spring equinox is nearly here. But what is it? [Video]

Spring is almost here — officially, at least.

The vernal equinox — also called the March equinox or the spring equinox — arrives on Tuesday, marking the start of the spring season for the Northern Hemisphere.

But what does that actually mean? Here’s what to know about how we split up the year using the Earth’s orbit.

What is the equinox?

As the Earth travels around the sun, it does so at an angle.

For most of the year, the Earth’s axis is tilted either toward or away from the sun. That means the sun’s warmth and light fall unequally on the northern and southern halves of the planet.

During the equinox, the Earth’s 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. That’s because on the equinox, day and night last almost the same amount of time — though one may get …