It's the winter solstice. Here are 5 ways people celebrate the return of light

On Yalda night, the Iranian winter solstice tradition, observers gather with family and read classic poetry aloud to greet the returning sun. (Jasmin Merdan/Getty Images)

It's officially the start of a new season. Winter solstice, which falls on Thursday in the Northern Hemisphere, marks the shortest day and longest night of the year. From now on, the days become longer and nights become shorter.

This year, the solstice occurs at 10:27 p.m. ET, the exact moment the Earth reaches its maximum tilt away from the sun.

But while for some it might be a reason to go to bed early, for many, the day calls for celebration. Since before recorded history, the winter solstice has traditionally meant a time of renewal and ritual for people all over the world.

Here are some ancient winter solstice celebrations from both hemispheres and how they're marked.

Shab-e Yalda

For centuries, Iranians around the world have gathered on winter solstice to celebrate Yalda, meaning birth or rebirth. The holiday dates back to the Zoroastrian tradition, and is believed to be a dedication to the sun god Mithra. Also celebrated in many Central Asian countries such as Afghanistan, Azerbaijan, and Uzbekistan, Yalda is a time when loved ones gather to eat, drink, and read poetry through the night and welcome the sun. Nuts and fruits such as pomegranates and watermelons are symbolic, as their red hues represent dawn and life. The holiday represents the victory of light over darkness.

Dongzhi

In Chinese, Dongzhi literally means "winter's arrival," and is one of the solar terms in the traditional Chinese calendar. The occasion signifies a turning point in the year when yin energy transitions to the positive energy of yang as the days grow longer. Traditionally celebrated as an end-of-harvest festival during the Han Dynasty, today it is an important time to spend with family and eat a hearty meal of tangyuan (glutinous rice balls) or dumplings, depending on what part of China one lives in.

Inti Raymi

An actor performs as the Inca Emperor in a recreation of an ancient ritual during the Inti Raymi Festival in Cuzco, Peru, (Jose Carlos Angulo/AFP via Getty Images)

Peru's winter solstice is celebrated in June and honors the Incan sun god Inti (Quechua for "sun"), the most revered god in the Inca religion. Banned during the first years of the Spanish conquest, the festival has since been resurrected and now takes place in the city of Cusco, once the center of the Incan Empire. Festivities include feasts and mock sacrifices that honor historic rituals.

Soyal

For the Native American Hopi tribe in the Southwest, the Soyal ceremony is one of the most important ceremonies of the year. December is the month when protective spirits called katsinas bring the sun back from its long slumber. Lasting up to 16 days, ceremonies include gift-giving, dancing, and storytelling, and are mostly performed in sacred underground chambers called kivas. The festival marks a time for prayer and purification.

Toji

Monkeys sit in an orange spa for the winter solstice at the Ueno zoo in Tokyo in 2007. Orange spas are a Japanese winter solstice tradition. (Toshifumi Kitamura/AFP via Getty Images)

In Japan, the winter solstice comes with several rituals and customs to welcome the return of the sun. One custom that dates back hundreds of years involves taking a hot bath with yuzu, a citrus fruit known for its healing properties. Other traditions include eating a winter squash called kabocha, and foods that contain the "n" sound (like udon), as they are believed to bring good luck.