1. The first day of autumn is known as the autumnal equinox. On this day, the number of hours of daylight and darkness are equal. This is because the sun is aligned with the center of the Earth between the north and south of the planet. The other equinox occurs in the spring, which arrives in the third week of March in the Northern Hemisphere.
2. Yellow, orange and variations thereof always reside in the pigmentation of tree leaves, but they are overpowered by the abundance of green from the chlorophyll in the leaves. Come autumn, when the sun weakens and days grow shorter, the amount of chlorophyll in leaves diminishes, allowing the other pigments in the leaves to show through. Red and purple leaves are actually caused by the presence of sugars from sap that is trapped inside of the leaves.
Evergreen trees will not lose their leaves like deciduous trees. Their leaves, also called needles, are covered with a thick wax. This wax protects the inner components of the needles, preventing them from freezing.
3. Fall is a peak migration time for many species of birds. During autumn, birds will fly to other areas seeking more hospitable climates. The Arctic tern journeys about 11,000 miles each way for its annual migration. That is like going all the way across the United States about three and a half times
4. Contrary to popular belief, squirrels who have spent the entire autumn collecting acorns and other foods do not hibernate for the winter. Rather, they spend the majority of their time in nests they built to shelter them from harsh weather. When squirrels do come out in winter, they are usually tunneling under the snow to find the food they buried during the fall.
5. You’re bound to see pumpkins as part of autumn decor. The pumpkin was first named by the Greeks. They called this edible orange item “pepon,” which means “large melon.”
6. Autumn also signals another colorful spectacle apart from the tree leaves. The aurora borealis, also known as the Northern Lights, tends to be visible this time of year. This is because geomagnetic storms are about twice as likely to occur during the fall thanks to cool evening weather.