The Sun has been flaring up this week, which means skywatchers as far south as Vancouver, Halifax, or New York City may get a glimpse of the Northern Lights before dawn breaks on Saturday.
According to the National Oceanic and Atmospheric Administration (NOAA), which helps keep tabs on space weather, the Sun spat out a high-energy flare on Wednesday at 7:18 AM EDT. You can follow NOAA’s forecast of auroral activity at this link.
Solar flares are intense flashes of light created by the tempestuous conditions near sunspots. Because the Sun’s light takes about eight minutes to reach Earth, solar observatories notice them almost immediately.
However, flares are sometimes accompanied by a related phenomenon called coronal mass ejections (CMEs)—eruptions of high-energy plasma that travel slower than light speed. The Wednesday flare likely heralds the arrival of a CME at Earth over the weekend, and suggests the Sun is becoming active again after two years of relative tranquility.
When the plasma blast hits, it will rain charged particles down into our atmosphere.
Auroras, the entrancing ribbons of light frequently seen in high-latitude regions, can be significantly amplified by CMEs.
The lights are created when the solar wind, a stream of charged particles emitted by the Sun, crashes into Earth’s atmosphere and magnetosphere. The particles are drawn into trajectories along magnetic field lines, which is why they get pulled to the magnetically powerful poles.
As the particles lose energy, they collide with elements in the upper atmosphere, creating shimmering bands of light in the night sky (auroras are always happening, but the Sun outshines them during the day.)
CMEs are like solar wind gusts on steroids. As an expected tidal wave of charged particles bears down on Earth on March 23, the Northern and Southern lights are likely to be much more intense at the poles and will creep down into lower latitudes, too.
Solar storms, also known as geomagnetic storms, may produce spectacular visual effects, but they aren’t all sunshine and sky rainbows. The Sun has been known to unleash ejections so powerful that they fry electronics, disrupt power grids, and cause communication blackouts.
In 1859, the largest solar storm on record, known as the Carrington event, shorted telegraph wires, which caused fires. Scientists think that if a Carrington-level storm hit Earth today, it cause trillions of dollars of damage to our infrastructure.
So if you’re lucky enough to catch an aurora this weekend, enjoy the gorgeous natural light show. Then, research how you can support the many ongoing efforts to protect our civilization from the Sun’s worst belches.
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