This video provides an explanation of the solstices and equinoxes, which are important astronomical events that mark the changing seasons.<b<br/>r/>

This video is part of the 8-part series, Earth’s Rotation and Revolution.

Annual ritual filled with music, chanting

Earth is now at the point in its orbit around the sun where the northern hemisphere is fully illuminated.

On this day, the sun is at its lowest point in the sky, your shadow is the longest and daylight is the shortest.

INTERVIEW – Chiara Ferragni on why this event is so important, on there being so much miscommunication about HIV/AIDS at amfAR generationCURE Solstice at Hudson Common at the Hudson Hotel on June 23, 2015 in New York City.

/ WS 2009 Pontiac Solstice front end parked on lawn between highway and dealer's lot / WS rear of dealership building / WS dealership front lot / WS row of Pontiac G6 sedans / WS reverse angle; row of G6 sedans / WS row of Pontiac G8s /...

WS of Saturn Curve wall sign; PAN RIGHT to car slowly turning on turntable; product specialist is narrating 2004 Saturn Curve concept car at Cobo Hall on January 14, 2004 in Detroit, Michigan (Footage by Getty Images)

WS Pontiac Solstice front end / WS rear end of car 2006 Pontiac Solstice montage at Cobo Hall on January 19, 2006 in Detroit, Michigan (Footage by Getty Images)

WS wall sign; PAN RIGHT to Pontiac Solstice revolving on turntable / MWS front end of car / WS passenger side, front end, and driver side profile of car 2005 Pontiac Solstice montage at Cobo Hall on January 14, 2004 in Detroit, Michigan...

WS front passenger side three-quarter view / WS rear end of car---Footage is 4:3 anamorphic. It will play back at 853x480.--- 2009 Saturn Sky Red Line montage at Cobo Hall on January 23, 2009 in Detroit, Michigan (Footage by Getty Images)

WS Pontiac Solstice GXP; front quarter passenger side view 2007 Pontiac Solstice GXP at Cobo Hall on January 17, 2007 in Detroit, Michigan (Footage by Getty Images)

Hippie Dancing in San Francisco

WS Pontiac Solstice concept roadster; a narrator behind the roadster starts speaking / WS front quarter driver side view of Solstice coupe / WS Dutch tilt of Solstice roadster revolving on turntable / WS dashboard / CU Pontiac front...

People gather at Stonehenge in Wiltshire to mark the Winter Solstice, and to witness the sunrise after the longest night of the year.

People take part in the winter solstice celebrations during sunrise at the Stonehenge prehistoric monument on Salisbury Plain in Wiltshire.



Stonehenge is a monument built on the alignment of the midsummer sunrise and the...

Roxane Mesquida at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

Zoey Deutch at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

Lydia Hearst at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

Camilla Belle at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

ATMOSPHERE - Models at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

Debby Ryan at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.

EVENT CAPSULE CHYRON - Kate Spade Saturday Summer Solstice Party

EVENT CAPSULE CLEAN - Kate Spade Saturday Summer Solstice Party

ATMOSPHERE - Fashion at Kate Spade Saturday Summer Solstice Party on June 20, 2014 in Los Angeles, California.