The Earth, and all life on it, would not exist without the sun; it is thus understandable that scientists take such an interest in how it works.
Its gravitational field combined billions of small asteroids into our world, its energy began the processes of life and its heat allowed complex life like humans to survive.
In the early 17th century, an astronomer named Galileo Galilee demonstrated that the Earth revolves around the sun, and that this sun had miniscule spots upon it, which he called sun spots. No further study was taken for several centuries, when the topic was revisited by Rudolf Wolf in the 1840s. He discovered that those spots were not only darker, but also significantly colder than the rest of the sun.
His work brought up more questions than it answered. What causes sun spots and how do they affect us here on Earth? To this day, these questions have not been fully answered, but much has been uncovered throughout the past two centuries.
One of the most interesting elements of sunspots is their strong connection with the Earth’s temperature. The first person to publish this idea was not a physicist, but rather an English economist by the name of William Jevons.
Looking over Wolf’s archive of sunspot activities, he noticed that sunspot activity and economic prosperity were closely linked. He believed that sunspots affected the Earth’s weather, thus changing crop output and influencing the economy. While his economic theory was never taken seriously, his ideas caused many scientists to investigate the connection between sunspot activity and temperature.
The lowest recorded sunspot activity occurred between 1650 and 1725, a period known as the Maunder Minimum. This period also coincided with the coldest portion of the mini ice age.
As the sunspot activity began to increase throughout the 1700s, Earth’s temperature rose, although it was still cold enough to be classified as the mini ice age (remember that it was during this “warming” period that George Washington crossed the frozen Delaware River, indicating temperature in the 20s). When the second lowest recorded sunspot activity occurred in the early 1800s, the Earth soon followed suit, cooling until the 1850s, soon after sunspot activity began to increase.
Interestingly enough, sunspot activity began reaching high levels in the late 1950s, and by the early 1980s the Earth began to warm, consistent with the 15-20 year lag which seems to occur between sunspots and temperature changes.
Sunspots began very slowly declining in number throughout the 80s and 90s, and from 2001 onward have been declining tremendously.
Many scientists who associate sunspots as the primary source of our temperature changes (such as the American Astronomical Society and the Royal Observatory of Belgium, major players in the study of our sun) predict a cooling phase to start within the next decade, intensifying throughout the 2020s and likely the 2030s even as others predict a warming of the Earth.
Time will tell who is correct.
