Sunspot AR2699 is directly facing Earth this weekend. If it explodes, the eruption would surely be geoeffective. However, the growth of the sunspot has stalled during the past 24 hours, prompting NOAA forecasters to downgrade the chance of a strong M-class solar flare to only 15%. Flares or not, this big sunspot is a beautiful target for backyard solar telescopes.
Sunspot AR2699 has developed an unstable “beta-gamma” magnetic field that harbors energy for M-class solar flares. NOAA forecasters have estimated a 15% chance of such explosions. That gives us a roughly one-in-six chance of something akin to the 1859 Carrington event, which hurled a huge CME directly at Earth, the largest ever observed. As we all know, flare of this magnitude would seriously affect modern communications and safety here on Earth. There just aren’t enough Faraday Cages to save everything! (Make one for your comms gear.)
At present, we are closing on the solar minimum, says WUWT. Until Feb. 4 2018, a total of 18 days (45%) had gone without sunspots. Then a large one, which surprised observers, rotated into view. It’s very near the Sun’s equator, such that if it fires off a solar flare and/or coronal mass ejection (CME), we could very well see it on a direct collision course with Earth.
Sunspot AR2699 has doubled in size since it appeared on Feb. 4th. As WUWT says, AR2699 contains two primary dark cores larger than Earth and a scattering of moon-sized magnetic condensations stretching more than 100,000 km across the surface of the sun.
This clip from NASA’s Solar Dynamics Observatory shows the sunspot expanding and turning toward Earth: