The ordinarily dark skies of states along the horizontal stretch, including Pennsylvania, Iowa, and Oregon, were lit up with a show of multicolored lights earlier this week. 

The National Oceanic and Atmospheric Administration (NOAA) claims the sun released two coronal mass ejections just a day apart on Nov. 1 and Nov. 2. These ejections blasted a magnetic field towards Earth as a result of an eruption in the sun’s atmosphere. 

When these ejections reached earth, they caused geomagnetic storms. Particles in Earth’s magnetic field emit light when they come in contact with these magnetic disruptions, displaying what we know as the Northern Lights. 

Typically, these Aurora sightings are limited to the poles of the Earth due to the weak magnetic field in those areas. When alien particles, normally electrons and protons, break through the earth’s magnetic field, they release energy, which is displayed as light. 

This geomagnetic disturbance disrupted the magnetic field as it brought these lights further south than usual, creating the unique event visible to residents of northern states. 

Scientists use the planetary K-index to measure the severity of geomagnetic storms on a scale of 9. Scores over 5 Kp indicate the presence of a geomagnetic storm. On Nov. 4, the index score remained between 6 and 7 Kp. 

These scores can be translated to units of magnetic latitude, which indicate the magnitude of the aurora’s southern reach. Using this chart, a score of 6 Kp translates to 54.2 on the magnetic latitude and signifies that the Northern Lights are visible as far south as Great Falls, Montana. 

Lower magnetic latitude values relate to more southern destinations. To put this in perspective, a magnetic latitude value of 42.5 would make the lights visible in San Francisco. However, this would require a planetary K-index score far above 9, which is nearly impossible in today’s astronomical climate. 

Simply because the Northern Lights had reached these southern destinations does not mean that they may be visible in all places. Spotting the Northern Lights is similar to stargazing in that the best results are found in clear skies, far from large cities. 

Unique sights such as these define the beauty of astronomical science.