X5.1 solar flare, G4 geomagnetic storm watch

Original Article ↗ Hacker News Discussion ↗

Cloud cover & viewing conditions

  • Many in Northern Europe (UK, Ireland, Germany) report heavy cloud and rain, limiting visibility despite being at good latitudes.
  • Some got brief views through gaps, e.g. in Scotland and Switzerland; others note Ireland often gets aurora but rarely clear skies.
  • North American commenters repeatedly mention the ironic pattern of aurora coinciding with cloudy nights, though many had clear skies this time.

Timing, forecasts & what’s actually hitting

  • Confusion over “16 UTC” is clarified as 16:00, later revised to 12:00 UTC.
  • Several point out that the strong G4 storm initially came from earlier X1-class flares, not the X5.1 CME, which had not yet arrived.
  • Discussion of SWPC forecast tables (Kp values over time) and how to interpret them; emphasis that a bigger flare does not guarantee a bigger geomagnetic impact.

Magnetic field, prediction limits & data sources

  • Detailed explanation: actionable details only arrive ~1 hour before impact, from L1 satellites (e.g. ACE) measuring the interplanetary magnetic field.
  • Southward (negative) Bz below about -10 nT for several hours greatly boosts auroral activity; strong but northward fields can yield little visible effect.
  • Models like WSA–ENLIL do not predict magnetic orientation, so they act mainly as “heads up” to watch L1 data.
  • Links shared to auroral ovals, magnetometer dashboards, and global observatory networks; one commenter wonders why no live global magnetometer map exists.

Intensity, Carrington-style worries & infrastructure

  • Multiple questions about a “Carrington event 2.0”; responses: this is definitely not such an event, and doom is considered unlikely here.
  • Mention of stronger historical events (including Miyake events) but no consensus on modern risk in this thread.
  • US grid operator PJM issued a geomagnetic disturbance warning (K7+), but no corrective actions were required; other grids reported little or only weather-related issues.

Global aurora observations

  • Numerous reports of naked-eye aurora at unusually low latitudes: down to the US/Mexico border, Kansas City, Denver area, northern Missouri, South Carolina, northern Minnesota, southern Alaska, Switzerland, Germany, El Salvador, Victoria (Australia), etc.
  • People remark on bright red skies, magenta hues, and seeing aurora for the first time far from polar regions.
  • Some missed the peak due to sleep, clouds, or misjudging which night would be best.

Satellites, ISS, rockets

  • Question about whether this could destroy the ISS is answered with a firm “no”; crew instead would get spectacular auroral views.
  • Concern raised (without detailed answers) about impacts on constellation-style satellite networks.
  • A Mars-bound launch (New Glenn / ESCAPADE) was postponed explicitly due to elevated solar activity and space-weather risks to the payload.

Aurora colors, photography & tools

  • Commenters note this storm’s aurora appeared predominantly red compared to prior green/pink displays; explanation linked to altitude/energy of interactions in the atmosphere (via external references).
  • Multiple people emphasize that phone cameras reveal structure and color better than the naked eye.
  • Various tools and galleries are shared: real-time auroral ovals, webcams, weather-service photo galleries, and Swiss and European time-lapse collections showing the storm’s spatial extent.

Miscellaneous

  • Side tangents include UK regional terminology and Scottish independence history, plus jokes about “raining protons” and harvesting energy from solar eruptions, hurricanes, or volcanoes.