If you got a chance to don some proper eclipse eyewear and look up at the sun during the partial solar eclipse on October 23, you may have noticed a dark spot on the face of the sun. You weren't imagining things. What you saw was a sunspot so large, it was visible to the naked eye (with proper eye protection in place).
The sunspot, named AR 12192, is the biggest in 24 years. It strolled across the sun's face, letting off 10 good-size solar flares along the way. "Despite all the flares, this region did not produce any significant coronal mass ejections," said Alex Young, a NASA solar scientist. What we can learn from this is that large sunspot regions don't always spew major (massive clouds of solar particles), the kind of solar events that can impact electronics on Earth.
AR 12192 grew to about 80,000 miles across. Despite its grand size, the sunspot was only the 33rd largest region out of 32,000 that have been tracked since 1874. It's the biggest seen since 1990. The sunspot is currently hiding on the far side of the sun, but NASA says it could wind its way back around in a couple of weeks.
NASA released an image of the sunspot on its journey across the front of the sun, tracking the region from October 17 to October 29. It's fascinating to follow it as it rotates along a straight path, the dark spots coming together to form what looks like a shadowy set of islands.
The sunspot and its flares are giving scientists plenty of fodder for study. "Having so many similar flares from the same active region will be a nice case study for people who work on predicting solar flares," said Dean Pesnell, a project scientist at NASA's Solar Dynamics Observatory. "This is important for one day improving the nation's ability to forecast space weather and protect technology and astronauts in space."