spaceSpace and Physics

Jupiter-Sized Sunspot Largest for 24 Years


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

10 Jupiter-Sized Sunspot Largest for 24 Years
Sertio Castilo. A close up of an X-class flare emerging from the area around the largest sunspot in two decades (LS waiting for photo credit))

Anyone who observed Thursday's solar eclipse with the help of instrumentation or internet would have noticed an enormous group of sunposts close to the center of the sun. It now turns out these spots are the largest in 24 years and are creating some pretty stormy space weather.

Astronomers first sighted the sunspot region designated AR 2192 on October 18. It had been building on the far side of the sun and that day, rotated into view already huge.


NASA/SDO. The progress of AR12192 as seen from the Helioseismic Magnetic Imager on NASA's SDO

As the sun's rotation brought it front and center, it has continued to grow, leading to some dramatic comparisons.

Alex Young. Feeling small yet?

Sunspots have cycles that are normally eleven years long, but this one is irregular. After a peak in early 2012, sunspot numbers dropped for a while, before surging again towards the end of last year. Despite this recovery, sun spot numbers for this cycle are down from the last one, but AR 2192 is making up in size what is lacking in frequency. We can't spot the peak until a fair way after it has passed, but in the meantime, we are getting spectacular images such as these.



Sunspots represent cooler areas of the sun, but they are frequently associated with electromagnetic storms. AR 2192 one has been no exception. So far there have been five solar flares, four of them of the strongest X class. A flare as large as the X3.1 that occurred on Friday could do a lot of damage to the Earth's communication systems if directed our way, but so far the blow has been tangential enough that the effect has been limited to a temporary radio blackout.

NASA/SDO. Ultraviolet image of the largest of the solar flares.

If you're wondering about the dark line just above the center of the sun...we're curious too.


H/T io9

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