In the movie Europa Report, a spacecraft named Europa One on humanity's first crewed mission to Jupiter's icy moon of the same name is hit by a solar storm, causing a loss of communication with Earth. The storm is caused by a coronal mass ejection (CME), a violent release of part of the Sun's magnetic field and high-energy plasma, which overloads the communications systems of the spacecraft and cuts them off from any support from Earth.
Although the story of Europa One is fictional, the threat posed by extreme solar activity is very real. Solar flares and coronal mass ejections (CMEs) occur frequently, and have impacted Earth before. In 1859, a powerful solar storm caused widespread destruction of the then-new telegraph technologies. Today, as society is even more reliant on communication technology, a similar event would have catastrophic consequences.
On April 19th, NASA reported that two powerful solar flares had erupted from the Sun, with potential consequences ranging from disruption of the electrical grid to radio communication and navigation signal interference. These flares also pose a significant risk to astronauts in space, who are exposed to harmful radiation. Additionally, because electromagnetic radiation travels at the speed of light, by the time a flare is detected, it has likely already caused damage.
During a solar storm, increased levels of X-ray and UV radiation ionise the ionosphere, interfering with radio waves and degrading or completely disrupting communication signals. This poses a serious threat to anyone who relies on communication for survival. While the solar flares themselves do not pose a direct threat to humans, the impact on our infrastructure could be devastating.
On Earth, our magnetic field is generated by the motion of the planet’s liquid metal core. On the Sun, however, it is liquid core all the way down, so to speak. A mostly massive ball of hydrogen roils and ripples under the competing forces of gravity and fusion, creating powerful magnetic fields unparalleled anywhere else in the solar system.
That magnetic field is always changing, and, like a slowly winding coil, it is constantly moving toward the moment when everything snaps. For the Sun, that happens on a roughly 11-year cycle which ebbs and flows between periods of high and low solar activity. When we’re at a low point in the cycle, sunspots, solar radiation, and ejected material from CMEs and solar flares are at their minimum. At the other end of the cycle, the opposite is true. Sunspots, solar flares, and CMEs increase in frequency until the Sun hits solar maximum. Then the magnetic field flips and things calm back down, before winding up again.
Right now, we’re headed toward the solar maximum of solar cycle 25 (referencing the number of cycles since astronomers started tracking). The peak is expected to occur in July 2025. Consequently, we can expect an increase in solar flares and other solar activity over the next couple of years. The good news is, it’s unlikely that we’ll be hit by anything powerful enough to really mess things up. After all, we got hit by an M-Class and X-Class flare last night, and no one aside from a few incredibly dedicated scientists even noticed.