Scientists scratched their heads this week over a massive sunspot, partly because it posed no threat to human civilization. The burst of solar magnetic activity, one of the biggest on record, whipped up powerful flares but didn't spew coronal mass ejections (CMEs) that can bring down Earth's power grids or damage satellites, Space.com reports. "It tends to be the case that when you have a big flare, you generally get a big CME," says NASA scientist C. Alex Young. The National Oceanic and Atmospheric Administration monitored the sunspot (called Active Region 12192) for "geoeffective" CMEs just in case, Tech Times reports, and there's a chance that AR 12192 will still be active after its two-week trip on the sun's far side. "Some have gone around a couple times," says Young.
Another head-scratcher: Scientists still don't know how sunspots grow as big as AR 12192, which was almost 80,000 miles wide or about the size of Jupiter—the largest sunspot in 24 years, the 33rd largest since 1874, and, The Sun Today notes, 14 times bigger than Earth's surface. Scientists do know that the sun is near its solar maximum—the apex of its solar cycle, which comes every 11 years—so magnetic energy is bubbling up. But why in one place rather than another? "I guess a good analogy is when you twist a rubber band or piece of string," says Young. "Why do, say, three knots or bunches form instead of two or four? The physics is probably too complicated for us at this point." If AR 12192 does come back around, you should only observe it with eclipse glasses; Space.com helps out with a "sun observation guide." (Did sunspots have anything to do with the sinking of the Titanic?)