For the most part, this past February 15 seemed like any ordinary day. We recognized Flag Day, marking the Canadian maple leaf flag that was first raised in Ottawa in 1965.
But things played out differently on the surface of the sun that day, with a huge explosion known as a coronal mass ejection (CME) hurling superheated gas (called plasma) into space at up to 1.6 million kilometres per hour.
The good news for us is that this intense so-called X-class flare event (the most powerful classification) occurred on the far side of the sun, with the particles moving away from us.
The sun is a huge ball of hot plasma, spanning the width of 109 Earths lined up side by side, like a string of pearls at its equator. The immense energy is produced at the sun’s core. Every second, 600 million tons of hydrogen is converted into 595 million tons of helium.
The remaining five million tons is pure energy that helps sustain life here on Earth. This has been going on for the past 4.6 billion years, and it will continue for another 4 to 5 billion more.
Over the sun’s 11-year solar cycle, internal magnetic-field lines begin to twist, building up energy. Eventually, this energy is released in solar flares, forming large loops of plasma—some that are tens of times the size of our planet—that are anchored to the solar disk.
However, there are times when the flare’s energy is so intense, a CME explodes off the surface, travelling through the solar system via the solar wind. On a calm day, the solar winds blow at about 350 kilometres per second, but a very intense explosion can accelerate them to as much as 2,000 kilometres per second.
When such a cloud of protons and electrons encounters the Earth, it can set off spectacular northern lights, a.k.a. the aurora borealis. On a typical day, about 20 flares are seen on the surface of the sun.
When our atmosphere interacts with a solar storm, it can be extremely dangerous for satellites. They can malfunction or be dragged down and destroyed as they burn up in the atmosphere.
This occurred with a geomagnetic storm that hit the Earth at the end of January, bringing down 40 of the 49 Starlink satellites SpaceX had just sent up. This new batch had not reached its operating altitude and fell out of the sky, burning up as they entered the atmosphere and costing about $20 million.
Another hazardous factor is that if the CME had been angled toward Earth, our planet could have been in serious trouble. Solar storms like these can destroy power grids, such as in the Quebec blackout of March 13, 1989, when transformers melted.
One of the most intense storms to hit the Earth was called the Carrington Event of September 1 and 2, 1859. Teletype machines were still able to transmit messages, even with the batteries disconnected.
There were even reports of paper and machines catching fire. The aurora was so bright that gold prospectors woke up in the middle of the night and started making breakfast, thinking the sun was rising.
At some point in the future, we will eventually be hit by another such Carrington Event. When it happens, power grids will be affected or fail. Because we rely so much on electricity and the Internet for our infrastructure, it will have a serious impact on our everyday lives.
We dodged a solar bullet on February 15. The present 11-year solar cycle is ramping up to its Solar Maximum—when the number of flares and sunspots reaches its 11-year peak and the star is most active—sometime in July 2025.
Bonus: from now till then, there will be a greater chance of seeing the shimmering northern lights.