The arrival of fall in the northern U.S. into Canada is now visible, and not just from out the window but from space.
NASA recently posted satellite photos showing how the changing foliage looks from above Earth as its Image of the Day.
"The changing of leaf color in temperate forests involves several causes and reactions, but the dominant factors are sunlight and heat. Since temperatures tend to drop sooner and sunlight fades faster at higher latitudes, the progression of fall color changes tends to move from north to south across North America from mid-September through mid-November," NASA stated.
"In late summer and autumn, tree and plant leaves produce less chlorophyll, the green pigment that harvests sunlight for plants to convert water and carbon dioxide into sugars," NASA continued. "The subsidence of chlorophyll allows other chemical compounds in the leaves—particularly carotenoids and flavonoids—to emerge from the green shadow of summer. These compounds do not decay as fast as chlorophyll, so they shine through in yellows, oranges, and reds as the green fades. Another set of chemicals, anthocyanins, are associated with the storage of sugars and give the leaves of some species deep purple and red hues."
Watch this video explaining more about the science behind the autumn color change and why some trees drop their leaves:
(H/T: Daily Mail)