The sun's peak of solar activity this year will likely be the quietest seen in at least 100 years, say NASA scientists who watch Earth's closest star daily.
Sunspot numbers are low, researchers said, even as the sun reaches the peak of its 11-year activity cycle. Also, radio waves that are known to indicate high solar activity have been very subdued.
"It's likely to be the lowest solar maximum, as measured by sunspot 'number,' in more than a century," wrote Joe Gurman, a project scientist for NASA's sun-observing mission Stereo, or Solar TErrestrial RElations Observatory. The current sun weather cycle is known as Solar Cycle 24.