Sun news: Triplet of space weather missions launch tomorrow

Sun News September 23: Triplet of space weather missions launch tomorrow

(11 UTC to 11 UTC)

Today’s top story: NASA and NOAA have announced that SpaceX will launch a triplet of missions tomorrow to study the sun and its solar wind. The Falcon 9 rocket will carry NASA’s Interstellar Mapping and Acceleration Probe (IMAP), the Carruthers Geocorona Observatory, and NOAA’s Space Weather Follow-On L1 (SWFO-L1). Together, these spacecraft will expand our ability to monitor the sun, measure the solar wind, and forecast space weather. Liftoff is set for 7:30 a.m. EDT from Kennedy Space Center, with a 90% chance of favorable weather.

• Flare activity: The sun stayed at low levels, producing 7 C-class flares over the past day.
  • Strongest: C4.2 from an unnumbered southeast region at 16:09 UTC on September 22.
  • Other notable flares: C3.8 (AR4227 at 17:26 UTC), C2.6 (AR4227 at 16:47 UTC), and C2.2 (unnumbered northeast region at 0:12 UTC). AR4227 was the most productive region with three C flares.
• Sunspot regions: The Earth-facing side of the sun shows 10 numbered active regions.
  • AR4217 (southwest, beta-gamma) gained a gamma configuration.
  • AR4226 (south-central, alpha) showed modest growth.
  • The rest of the regions remained small, stable, or slowly decayed.
• Blasts from the Sun? No Earth-directed CMEs appeared in coronagraph imagery. A striking prominence, which you can see below, erupted on the sun’s far side and is not Earth-directed.
• Solar wind: The solar wind surged. Speeds climbed from 300 km/s at the start of the period to 669 km/s, peaking at 812 km/s at 21 UTC on September 22. The IMF rose to moderate levels, and the Bz flipped between north and south before ending northward.
• Earth’s magnetic field: Conditions ranged from quiet to unsettled (Kp = 2–3). The Kp index was just below 3 at the close of the period.

What’s ahead? Sun–Earth forecast

• Flare activity forecast: Mostly C-class activity is expected, with a 35% chance of an M-class (R1–R2) flare, most likely from AR4220 or AR4217.
• Geomagnetic activity forecast:
  • September 23: Unsettled-to-active conditions expected, with isolated G1 (minor) storms likely and a slight chance of G2 (moderate) storms from the corotating interaction region (CIR) impact.
  • September 24–25: Conditions should ease from quiet to unsettled as coronal hole effects diminish.

Sun news September 22: Solar wind set to rise; auroras possible

(11 UTC to 11 UTC)

Happy September equinox, a day of balance between night and day and enhanced chances for auroras. And sure enough, auroras are forecast today! Earth is bracing for the arrival of a fast solar wind stream and a complex knot of solar wind known as a corotating interaction region (CIR), both expected to reach us today. This could push geomagnetic activity to G1 (minor) storm levels, with a slight chance of G2 (moderate) conditions when the CIR first hits. Aurora watchers, stay alert.

• Flare activity: Solar activity stayed at low levels with 12 flares in the past 24 hours, all in the C (common) range.
  • Strongest: C6.6 from AR4223 at 21:16 UTC on September 21.
  • Other notable events: C3.3 (AR4224 at 17:43 UTC), C2.3 (AR4220 at 17:01 UTC), and C2.7 (AR4217 at 21:31 UTC). AR4217 kept busy with multiple smaller C flares, including three during the early hours of September 22.
• Sunspot regions: Ten numbered regions are currently on the solar disk.
  • AR4220 (southwest, beta-gamma) stayed the most active and complex, though its trailing spots showed some decay.
  • AR4223 (south-central, alpha) decayed to a simpler form but still managed the strongest flare of the day.
  • AR4217 (southwest, beta) added intermediate spots and stayed moderately active.
  • AR4224 (south-central, beta-gamma) continued to grow and produced one of the larger C flares.
  • Other regions remained small, stable, or in slow decay.
• Blasts from the Sun? No Earth-directed coronal mass eejections CMEs appeared in coronagraph imagery. Several prominence eruptions were spotted on September 21, but none are Earth-directed.
• Solar wind: The solar wind stayed slow, below 300 km/s. The interplanetary magnetic field (IMF) was weak and the Bz flipped gently between north and south. A rise in speed and density is expected later today as the fast solar wind arrives.
• Earth’s magnetic field: Earth’s magnetic field stayed quiet yesterday (Kp = 0–2). Forecasts call for unsettled-to-active conditions, with isolated G1 (minor) storms possible today as the fast solar wind arrives. A slight chance exists for G2 (moderate) conditions when the corotating interaction region hits. Conditions should ease back to quiet-to-unsettled by September 23–24.

The sun in recent days

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Bottom line: Sun news September 23, 2025: NASA will launch 3 missions tomorrow to study the sun and its influence on the solar system.