On October 27, 2003, the Sun came off the heels of emitting some massive, X-class solar flares. Just the day before, at both 650 and 1815 UTC, the Sun launched two flares from sunspots 486 and 484, respectively. They were expected to create aurorae after striking Earth’s magnetic field sometime on October 28. Little was it known at the time that this event would pale in comparison to what was coming in only a matter of days, if not hours (Phillips, 27 Oct.).
The next day, October 28, at 1110 UTC, the Sun emitted a massive X17.2 solar flare, which registered third all-time in recorded history. This flare, which came from sunspot 486—at this point, also observable from Earth under proper viewing conditions—also launched a coronal mass ejection (CME) towards Earth at a blazing speed of 2125 km/s, and consequently, an S3 solar radiation storm resulted (Phillips, 28 Oct. and 30 Oct.). However, due to the strength of this event, the SOHO satellite was unable to calculate an accurate density of the flare and CME (Phillips, 28 Oct.). This storm, known as a proton storm, wreaked havoc on the aviation industry, as planes were guided to fly at around 25,000 feet as opposed to 35,000 feet due to radiation exposure concerns (Phillips, 30 Oct; Young). This inconvenience caused higher fuel consumption amounts and thus a higher cost for airlines to operate during this period. Additionally, the SOHO satellite had to be placed into safe mode so it could brace the impact from this flare (Young).
However, the Sun was not finished just yet. On October 29, sunspot 486 ejected yet another solar flare, this time of the X11 variety (Phillips, Oct. 29). Meanwhile, the CME emitted on the 28th hit the Earth in under 18 hours, creating auroras that were visible as far south as Orlando, Florida and Houston, Texas in the United States (Young; Phillips, 29 Oct. and 4 Nov.). About a week later, on November 4, 2003, the Sun emitted a solar flare that clocked in at an X28, the largest on record (“The Most Powerful Solar Flares”). This was one of the most active periods of solar activity in recorded history, and it remains the most active since the beginning of the new millennium.
The October 28 solar flare and subsequent CME generated plenty of discussion and intrigue in solar weather and activity. It and the other massive ejections within this timeframe have since earned the nickname of the “Halloween Storms of 2003,” now among the most widely studied and well-known solar weather events (Dunbar). More importantly, it caused widespread problems around the globe. Power was affected from New Jersey to Sweden—nuclear plants in the former had to have their output decreased in order to prevent blackouts, while the latter experienced widespread power outages due to an excess of electric activity on its power grids. Outside the atmosphere, control of satellites in orbit was lost, including one Japanese satellite that was deemed a total loss. The International Space Station’s...