Solar wind
  speed: 606.9 km/sec
  density: 1.33 protons/cm3

X-ray Solar Flares
  6-hr max: C8 0041 UT Nov30
  24-hr: M2 1607 UT Nov29

Sunspot number: 74


REALLY BIG SUNSPOT ALERT: Yesterday, we issued a big sunspot alert. We were wrong. It's *really* big. This image from NASA's Solar Dynamics Observatory shows the behemoth emerging over the sun's southeastern limb on Nov. 30th:



NASA's Mars rover told us it was coming. Last week, Perserverance saw the giant sunspot through a cloud of dust in Jezero Crater. It was only days away from turning toward Earth--and now it is here.

From end to end, the sunspot group measures ~130,000 km, and at least four of the sunspot's primary dark cores are individually larger than Earth. These dimensions make it an easy target for safely-filtered backyard telescopes. If you don't have a solar filter, try this simple projection technique instead.

On Nov. 29th, amateur astronomer Andy Devey watched the sunspot's approach from his observatory near Mojácar, Spain:

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"This is an almost three hour look at the active region rolling around the sun's eastern limb," says Devey. "It was sizzling with C-class solar flares."

On Nov. 28th, the sunspot produced an M6-class solar flare. However, the blast site was partially eclipsed by the edge of the sun. The flare's true intensity may have been X-class. Now that the sunspot is turning to face Earth, future flares will be geoeffective.

Solar wind
  speed: 406.1 km/sec
  density: 1.66 protons/cm3


X-ray Solar Flares
  6-hr max: C3 0535 UT Dec02
  24-hr: C6 1014 UT Dec01


Sunspot number: 175


EVEN CARRINGTON WOULD BE IMPRESSED: On Sept. 1, 1859, English astronomer Richard Carrington sketched the most famous sunspot in history. While Carrington was watching an image of the sun projected on a screen, the sunspot produced a blinding X45-class solar flare, followed two days later by a planet-wide geomagnetic storm. We call it the "Carrington Event."



How does today's giant sunspot compare to Carrington's? Here is the answer:







The image shows Carrington's drawing of the 1859 sunspot inserted to scale on a Dec. 2, 2025, image of sunspot complex 4294-4296. They're about the same size. The surface area of Carrington's sunspot was ~2300 millionths of the solar disk. The surface area of 4294-4296 is 2080 millionths, about 90% as large.



To be clear, 4294-4296 is actually two sunspots. Their close proximity makes them appear as a single behemoth--an unfair advantage vs. Carrington. Even so, strong explosions are likely. The crowding of the two sunspots' magnetic canopies raises the odds of reconnection and an X-flare of their own. Any explosions today will be geoeffective.

Solar wind
  speed: 686.0 km/sec
  density: 3.29 protons/cm3



X-ray Solar Flares
  6-hr max: M6 0250 UT Dec04
  24-hr: M6 0250 UT Dec04

Sunspot number: 227

STRONG SOLAR FLARE AND CME: New sunspot 4300 erupted today (Dec.4th @ 0250 UTC), producing a strong M6-class solar flare. At the same time, the US Air Force detected a Type II solar radio burst, which means a CME is probably emerging from the blast site. Meanwhile, giant sunspot complex 4294-4296 remains ominously quiet.

Solar wind
  speed: 610.5 km/sec
  density: 0.27 protons/cm3

X-ray Solar Flares
  6-hr max: C6 0309 UT Dec06
  24-hr: C6 0309 UT Dec06

Sunspot number: 133


MONSTER SUNSPOT FACES EARTH: If there's no X-flare this weekend, it will be a waste of a truly monsterous sunspot. To see it, try this simple projection technique. Even Richard Carrington would be impressed. The sunspot group has an unstable delta-class magnetic field that harbors energy for geoeffective explosions