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Google is celebrating on Tuesday the longest day of the year and the first day of summer with a Summer Solstice Google Doodle from Japanese artist Takashi Murakami. At 1:16 p.m. Eastern Tuesday, the Earth's Northern Hemisphere will be the closest it will come to the sun all year.

But while the Earth's Northern inhabitants are getting ready to hit the beach, Google hasn't forgotten that residents of the Southern Hemisphere are hunkering down for winter. So residents of countries such as South Africa, Chile and Argentina on Tuesday get to see a Winter Solstice Google Doodle also by Murakami.

Murakami is known for his sculptures and paintings that are highly influenced by Japanese Anime culture. The artist was named to the Time 100 in 2008, and worked with designer Marc Jacobs on reimagining the monogram of the French design house, Louis Vitton.

Topsy-Turvy Seasons

Google also celebrated June's Summer and Winter Solstice in 2010 with four different doodles for each hemisphere, with the eight doodles showing a different seasonal scene.

The search giant did something similar in 2009, showing a different seasonal doodle in the northern and southern parts of the Earth.

But in 2008 Google offered only a Summer Solstice doodle--the first time the company marked the seasonal event.

Beyond marking the first day of summer and being the longest day of the year, the Summer Solstice is also an important day on the Pagan calendar. For more than 100 years, people have gathered at Stonehenge in England to celebrate the Summer Solstice. This year, an estimated 18,000 people gathered at the historical monument on early Monday to welcome the new day, according to The Telegraph.

Summer Solstice June 21, 2011: Quick Facts on Longest Day of the Year

Summer Solstice is the day in a year when the Sun reaches its northernmost point in the planet Earth's sky.

June 21, 2011 - the date this year traditionally marks a change of seasons - from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere.

Summer solstice occurs on the longest day and the shortest night of the year in the northern hemisphere

Winter solstice occurs on the shortest day and longest night of the year. December 22 is the date for Winter solstice this year.

Thousands of people gather at sunrise at the ancient Stonehenge monument to see the sun rise through the 4,000 year old solar monument on Salisbury plain in southern England.

According to NASA, the Sun continues to rise over Stonehenge in an “astronomically significant way.”

NASA explains: Standing within Stonehenge, facing north-east through the entrance towards the heel stone, one can sees the sun rise above the stone at summer solstice.

Travellers watch as the sunrises over the Stonehenge monument near Salisbury at a summer solstice on June 21.REUTERS/Paul Hackett

Summer Solstice, Shifting Spring The First Day of Summer June 21

Tomorrow is our summer solstice—the longest day of the year here in the Northern Hemisphere. For folks in the Southern Hemisphere, tomorrow is the winter solstice, the shortest day of the year. The solstices occur thanks to the tilt of the earth. Humans have been recognizing and celebrating the solstices throughout history; Stonehenge is just one example. But we humans are not the only creatures that pay attention to day length. The life cycles of myriad plants and animals are controlled by the length of the day.

Many plants and animals are sensitive to the photoperiod, or day length. As day length grows longer throughout the springtime, many species of plants begin to flower. Other plants are triggered to reproduce when the day length becomes shorter. In these plants, a protein is actually responding to the number of hours of darkness, not to the hours of light. Many animals respond to day length, too. For many bird species, a critical day length initiates their reproductive maturation and is their cue to begin migrating. Decreasing day length also prompts hibernation in many animals. In all of these examples, photoperiod is controlling organisms’ phenology—the timing of life events, like plant flowering and bird egg laying. Phenology is often tied to the seasons, because of organisms’ responses to day length.

Phenology can also be controlled by other factors, like temperature and the amount of rainfall. As the days grow warmer because of climate change, the timing of organisms’ life cycles is shifting. Spring happens earlier than it used to, and many springtime life events are happening earlier too. In major 2003 study of nearly 700 species, including birds, insects, frogs, flowering plants, and trees, 62% of species’ life cycles had shifted over an average of 45 years. Birds and frogs bred earlier, migrating birds and butterflies arrived sooner, and plants flowered and buds burst earlier.

This is likely leading to a widespread phenological mismatch; while some organisms are responding to earlier springtime temperatures, other organisms are still tracking day length. This means that insects emerge ready to feed on particular plants, but the plants are not yet edible. The insects don’t get their food, and the plants don’t get pollinated. Or migrating birds arrive hungry, and their food source has not yet ripened.

It is difficult to know to what extent phonological mismatches are taking place. A proper study of phenology requires a lot of data—many widespread observations of when a particular plant is flowering, or when and where a particular migratory bird is present. This is where you come in. The National Phenology Network has a citizen science program that allows people across the country to record their observations of plants and animals. This crowd-sourced data will be used to determine the extent and effects of shifts in the timing of organisms’ life cycles.