Between wildfire smoke, rain and a rather "quiet" sun we're currently in an aurora drought. Large sunspots always make us hopeful that will end. Especially when those spots harbor complicated magnetic fields that tangle together and release their energy in powerful solar flares.
That's exactly what happened Thursday morning, June 29, as I ate my shredded wheat. A large sunspot group numbered 3354 shot off a moderately powerful M-class flare. Since the group faces the Earth, there's a fair chance that any material it blasted into space is headed in our direction. If so and under the right circumstances, we might get a chance at seeing the aurora.
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In the meantime, I want to encourage you to don your (undamaged) solar eclipse glasses left over from the August 2017 eclipse and have a look at the sun. You can also use a #14 welder's filter. Both are safe. I easily saw the monster sunspot through my welder's glass without any magnification. Naked-eye sunspots have been a regular occurrence every month for more than a year, a sure sign that we're headed toward the peak of the sun's 11-year solar cycle. The current one, Cycle 25, has been vigorous and may peak as soon as next year when large sunspots may become even more frequent.
Through a small, filtered telescope the sunspot group is a beautiful mess of large and small spots. Individual spots contain one or more dark cores called umbras wrapped in a lighter, filamentary region or penumbra. Sunspots are dark because strong magnetic fields concentrated in the regions insulate the spots from heat rising from below, keeping them cooler. While the sun's surface boils at around 9,900 degrees Fahrenheit (5,500 degrees Celsius) sunspots chill out around 6,500 degrees Fahrenheit (3,600 degrees Celsius). The several thousand-degree temperature difference makes them look dark in contrast.
Flares are normally only visible in specific wavelengths (colors) of light like ultraviolet and deep red, called hydrogen alpha . A modest flare releases the energy equivalent of 10 million hydrogen bombs. The most powerful produce a billion times the energy. Our tiny brains can barely conceive of such force, yet for a star, it's routine. I often remind myself that we live around a star, the same as the ones that twinkle at night. Even if we can't feel their heat or see their surfaces, the sun reminds us of their true nature.
I'll be watching the giant spot group (and hope you will, too) and report back if aurora is in the offing. In case you've misplaced or damaged your eclipse glasses, you can select from a variety of different safe filters at Rainbow Symphony . If you're buying from Amazon, make sure the glasses are CE- and ISO-certified.
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