Scientists thought the exceptionally quiet Sun of 2008 might be slipping into a decades-long lull. Instead the trend reversed, and a NASA study published in September 2025 found that its underlying solar-wind activity has been strengthening for nearly two decades.

Solar-wind speed, density, temperature, pressure and magnetic-field strength all rose after the deep 2008 minimum, reversing a decline that had persisted since the 1980s. The post Scientists thought the exceptionally quiet Sun of 2008 might be slipping into a decades-long lull. Instead the trend reversed, and a NASA study published in September 2025 found that its underlying solar-wind activity…