Understanding Solar Maximum and Minimum

By Miguel Moreno

That fiery ball in space does settle down every 11 years or so. It’s called the solar minimum, and the Space Weather Prediction Center indicates that this phase of low sunspot activity will continue for a few more years.

During a solar minimum, the sun has very few sunspots on its surface, which some speculate could affect the earth’s weather. In contrast, a solar maximum has more sunspots on its surface and solar activity is high.

“Usually a solar minimum lasts about a year or so, but then sometimes it can last for decades or even longer,” said Prof. Jason Kendall, an adjunct professor of astronomy from William Paterson University, in an interview with NTD News. “And that has happened in history, and those would be called a grand solar minimum, when there’s a dearth, an absence of sunspots.”

NASA
A sunspot rotates over the left side of the sun on Oct. 23, 2014. (NASA)

NASA reports that a grand solar minimum could potentially lower the temperature by .3 degrees Celsius if it were to happen. Kendall said this number is far lower than the warming of the earth NASA attributes to human beings.

But Kendall said it’s hard to predict something like a grand solar minimum, considering that scientists don’t fully understand them to begin with. Despite that, some have gone as far as to speculate that a grand minimum could even lead to a mini ice age.

The last time earth experienced a grand solar minimum was in the 17th century. Astronomers like Galileo would study sunspots by projecting the sun’s image onto paper with the help of a telescope.

“Galileo made a series of sunspot drawing in the summer of 1612,” according to an introductory class to astronomy uploaded by Kendall. “The 36 drawings illustrate the motion of sunspots across the disk—which is actually a sequence showing the rotation of the sun.”