The Northern Lights, 2024, photo by Sharon Rieck
On October 10th many people witnessed a rare event, the Aurora Borealis, right in our backyard on the Eastern Shore of Maryland. Auroras were visible as far south as Alabama.
While it was relatively faint to the human eye, it appeared brighter and more colorful in photographs. This is because a camera can collect light over a longer period of time and our eyes aren’t as sensitive to low light as a camera lens.
The Aurora Borealis was a surprise to many, but scientists knew that it was coming.
They witnessed a powerful solar outburst on October 8th. An enormous mass of charged particles erupted from the sun, triggering a severe G4-level geomagnetic storm when it arrived at our planet on Thursday. (Geomagnetic storms are rated on a scale of 1 to 5, with G1 considered mild and G5 labeled extreme.) The eruption was so powerful that it was feared that it might cause power grid disruptions and satellite disturbances.
The solar outburst, known as a coronal mass ejection (CME), was the result of a powerful solar flare that erupted from our star. Solar flares occur when tangled magnetic-field lines on the sun violently snap back into place. Upon hitting our planet, CMEs cause major disturbances in Earth’s magnetic field known as geomagnetic storms.
Beyond their beauty, the Northern Lights are a sign that our earth is protecting us. Our sun’s solar winds and CMEs can strip away the atmosphere (as it stripped away Mars’ atmosphere). Earth is protected by a strong magnetic field that forms around it like a shield, protecting our atmosphere from these particles. Earth’s magnetic field invisibly surrounds our planet; but on some days we can see it in action—the Aurora Borealis.
Our auroras are a visible spectacle of our magnetic field protecting us from the solar winds and CMEs (the difference between CMEs and solar winds is that the latter are continuous, and the former are stronger and can include plasma). Technically, the aurora is a result of disturbances in the magnetosphere caused by solar winds and CMEs, but I like my description better.
So how does earth have this protection? Planets’ magnetic fields are formed by the liquid iron in their cores. Earth’s size means that it has enough liquid iron to generate a formidable magnetic field. So, the aurora is not only beautiful and surreal, but it shows us in a dramatic fashion how our magnetic field is protecting us from our star’s eruptions.
And on Thursday, we witnessed a rare event, beautiful and reassuring. Our earth was protecting us like a windbreaker from the wrath of our star.
Angela Rieck, a Caroline County native, received her PhD in Mathematical Psychology from the University of Maryland and worked as a scientist at Bell Labs, and other high-tech companies in New Jersey before retiring as a corporate executive. Angela and her dogs divide their time between St Michaels and Key West Florida. Her daughter lives and works in New York City.
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