Why Did Sunspots Disappear for 70 Years? Nearby Star Holds Clues

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https://eos.org/articles/why-did-sunspots-disappear-for-70-years-nearby-star-holds-clues


Excerpt: Every 11 years, the number of spots dotting the surface of the Sun increases and decreases like clockwork. Astronomers have been tracking the 11-year sunspot cycle for more than 400 years, using it to better understand the chaotic magnetic field the Sun puts out. (The current solar cycle, number 25, started in 2019.) The timing of the solar cycle is remarkably consistent: Sunspot numbers rise and fall, rise and fall…except for that time that they disappeared and weren’t seen again for 70 years. That period of time, from 1645 to 1715, is known as the Maunder Minimum, named after 19th century British astronomers Edward and Annie Maunder. Astronomers still don’t understand why the Sun ceased making sunspots for 70 years, but a new analysis of more than 5 decades of measurements of nearby stars has identified one that might be undergoing its own Maunder-like minimum. The star, HD 166620, could help scientists understand this mysteriously quiescent period of the Sun’s history and unlock clues about how the solar dynamo functions.…

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