Solar activity goes through cycles. The main one is about 11 years long and its maximum is marked by powerful eruptions of electromagnetic radiation known as solar flares, as well as releases of plasma known as coronal mass ejections. The most powerful known flare happened in 1859 and led to telegraph stations catching fire across the US, and Northern and Southern Lights becoming visible in the tropics.
Host Dr Alfredo Carpineti spoke with Dr Ryan French, astronomer at the National Solar Observatory and author of The Sun: Beginner's Guide to Our Local Star, to find out about solar flares and what would happen if a massive one took place today.
You can listen to this episode and subscribe to the podcast on all your favorite podcast apps: Apple Podcast, Spotify, Google Podcast, Podbean, Amazon Music, and more. A transcript of the conversation is available here.


![A dense cluster of bright stars, each with six large and two small diffraction spikes, due to the telescope’s optics. They have a variety of sizes depending on their brightness and distance from us in the cluster, and different colours reflecting different types of star. Patches of billowing red gas can be seen in and around the cluster, lit up by the stars. Small stars in the cluster blend into a background of distant stars and galaxies on black.]](https://assets.iflscience.com/assets/articleNo/77446/aImg/81193/glittering-m.jpg)

