The Northern Lights are legendary. There are thousands of beautiful photos taken in Alaska or Canada that feature as the background for inspirational quotes all across the internet. Despite how notorious they are, it is extremely rare for most people to see them.
This is because living towards the equator is significantly more hospitable, however it also significantly decreases your chances of seeing the Aurora in its full glory. In short, the Aurora becomes visible because of the sun’s interactions with the earth and its atmosphere. Although it is a common belief that auroras are caused by solar flares, that isn’t entirely true.
First, huge ‘clouds’ of plasma in the sun’s atmosphere erupt. These are larger and slower traveling than solar flares, and so they pull back the magnetic field of the earth towards them. When the magnetic field snaps back it increases the activity of electrons in the atmosphere. The energy created by this process must be released eventually and so is emitted as photons, which our eyes here on earth perceive as lights of all different colors in the sky. What colors appear in an aurora are also determined by this process, since different atoms, ions, and molecules produce different colors. For example, green is monatomic oxygen, red can be either monatomic oxygen or diatomic nitrogen, and blue is ionized diatomic nitrogen.
Depending on the strength of the geomagnetic storm the aurora may cover a larger or smaller area of the earth. On May 10th the largest geomagnetic storm in twenty years hit earth’s atmosphere. Auroras were seen as far south as Nebraska through long exposure cameras on May 10th and CMEs (the plasma eruptions mentioned above) hit all through the weekend. There was a spectacular sky-wide aurora visible from Orcas on May 10th, and streaks could be seen for the next couple of days. Nearly every person on the island took a moment to go outside, stare up in wonder at the night sky, and snap a quick picture to send to every group chat they are a member of.
An aurora like the one that appeared in May will likely not be seen for several more decades again. Astronomers classified it as a G5, the highest level a geomagnetic storm can be. While that brought beautiful lights it also interfered with GPS, power, and satellites. There was no major infrastructure damage with thousands of people working to keep our modern technology running smoothly. Understandably, many people were nervous about what the storm would mean considering that, in 1989, a nine hour blackout was caused by a geomagnetic storm which affected all of Canada. Fortunately, the most we saw this year were radio communication interruptions.