Western Slope Skies - The Sun Awakens

Feb 19, 2021

Image of a Coronal Mass Ejection
Credit NASA/ESA

When it comes to astronomy, the dark night skies of the Western Slope command most of our attention. It can be easy to forget that the most important astronomical object actually lives in the daytime sky: the Sun!

Our Sun is a star, and a dynamic one at that. While some details about the inner workings of the Sun remain poorly understood, one thing we do know is that the Sun experiences an 11-year solar activity cycle. For the last several years, the Sun has been in a period of relative calm, known as solar minimum. As we head into 2021 however, the Sun is beginning to awaken. Our backyard star is entering a period of increased activity leading up to the next solar maximum estimated for 2025. The frequency of solar storms and flares is already on the rise.

Activity on the Sun can affect us here on Earth. During solar maximum, events known as coronal mass ejections, or CMEs, become common. CMEs are colossal eruptions of energetic, charged particles from the Sun’s outer atmosphere. Belched out by the Sun into space, these particles travel quickly, and can reach Earth in a matter of hours to days. Earth’s magnetic field generally does a good job of shielding us from these particles. However, during a large CME, the onslaught can overwhelm our magnetic field, potentially leading to problems here on the ground.

What kind of problems? On September 1st, 1859, British Astronomer Richard Carrington observed an odd flash of light while observing the Sun with his telescope. Hours later, strange events began to unfold around the globe. Telegraph systems, the newfangled invention of the day, ran without batteries and some operators were shocked. The northern lights lit up the sky as far south as Mexico and the Caribbean, and throughout Colorado. The Rocky Mountain News published the following report from a mining party camped high in the Rockies: “A little after midnight we were awakened by the auroral light, so bright that one could easily read common print. Some of the party insisted that it was daylight and began the preparation of breakfast.”

All of these incidents were the result of a massive CME colliding with Earth, now known as the Carrington Event. These stories from 1859 highlight the important connection between our planet and the Sun. While we haven’t been hit by another CME this large since, a repeat of the Carrington Event could be catastrophic today, given the extent to which our society now relies on electronics. Thanks to NASA, we now have solar probes that monitor the Sun 24/7/365, in part to give us some advance warning should another large CME head our direction in the coming years.

You’ve been listening to Western Slope Skies, produced by members of the Black Canyon Astronomical Society. This episode was written and recorded by Zach and Michelle Schierl.