Imagine the excitement of receiving a call from your mom, brimming with enthusiasm about the incredible spectacle of the aurora borealis that was supposedly heading our way. She caught wind of this awe-inspiring event from several reputable news outlets, and as someone with the northern lights on her bucket list, she couldn't contain her anticipation.
Naturally, I turned to my trusty aurora prediction app on my phone, expecting to find active alerts for the upcoming days. However, to my surprise, there were no indications of an imminent light show. In fact, the projected date for this supposed phenomenon fell well beyond the prediction window of my reliable sources. I found myself wondering: what was the reason behind the major news outlets' fervent claims of an impending grand display?
Delving into the depths of the matter, it became clear that approximately a month ago, a coronal hole had emerged on the sun. These temporary cool spots on the sun's surface typically allow solar particles to escape into space. Given that the sun rotates on its axis every 27 or so days, long-range forecasts speculated that this hole would reappear and align with Earth approximately 27 days later. The possibility emerged that this alignment might trigger the appearance of the aurora borealis at lower latitudes than its usual domain. However, even at the time, predictions did not anticipate a significant event—only a faint, greenish glow in the northern reaches of the United States. As it turned out, no solar storm materialized when that particular point on the sun returned.
The sun operates on an 11-year cycle, transitioning between periods of intense solar activity known as solar maximum and quieter phases referred to as solar minimum. Currently, we find ourselves on the ascending trajectory towards solar maximum, with solar activity predicted to increase until 2025. This development is particularly thrilling for avid aurora hunters, as heightened solar storms bring forth stronger and more vibrant displays of the northern lights. Furthermore, the stronger the aurora, the farther south its shimmering beauty extends.
But how does one determine when the aurora will be potent enough to witness? The answer lies in the quantification of disturbances within Earth's magnetic field by the Kp index. The National Oceanic and Atmospheric Administration (NOAA) publishes predictions of the Kp index approximately two days in advance. Additionally, they offer informative graphics illustrating the likelihood of experiencing the aurora based on the given Kp index. Generally, a Kp of 6 or 7 suffices for spotting the aurora in the northern United States. However, if you're willing to hold out for a Kp of 7 to 8, the luminous spectacle has the potential to become far more vivid and energetic.
It's important to bear in mind that the brightness of city lights and even the moonlight can drown out the ethereal dance of the aurora. To maximize your chances of witnessing a breathtaking show, planning your aurora-hunting escapades during a new moon and escaping light pollution is crucial. Personally, I mark the week surrounding the new moon on my calendar, hoping for an aurora alert during that window. Moreover, having a predetermined viewing site at your fingertips enables you to make a swift, spur-of-the-moment decision to jump in the car and chase down a celestial adventure.
Patience is undoubtedly a virtue in this pursuit, but rest assured that by closely monitoring the predictions and waiting for all the celestial factors to align, you just might bear witness to the most extraordinary show of your life. So keep your eyes on the skies and remain ever-ready, for the enigmatic aurora borealis beckons with its elusive allure, ready to captivate all those who dare to chase its magic.
Further reading:
Notes on NOAA’s extended, 27-day forecast and other forecast products can be found here:
Users Guide to The Preliminary Report and Forecast of Solar Geophysical Data
Washington Post - Sorry, but you probably can’t see the northern lights in the U.S. this week
Dark Site Finder - https://darksitefinder.com/maps/world.html
