APOD 1.4

September 23,2011: http://apod.nasa.gov/apod/astropix.html

As the sun crosses the celestial equator heading south, that is the defining factor of the autumnal season. Spring begins in the southern hemisphere, and autum begins in the northern hemisphere. During this time, the northern lights grow much bigger, thus making them much easier to see in the sky. The shimmering green light glows high above earth in the dark sky. Spring and autumn bring an increase in magnetic storms.