Lightning

To our ancient ancestors, lighting was in the domain of the gods. To the Greeks, only the most powerful of their gods, Zeus, could handle this mysterious and ultra-powerful force.

For the Norse, their corresponding god was Thor, from which we derive the name of the day Thursday. The Lakota worshipped a powerful spirit called the Thunderbird that manifested as lightning, representing sublime strength.

No matter where you looked, lightning was one natural phenomenon that got everyone’s attention. Even without sight, the terrible booming thunder that arose was enough to let anyone know something well beyond human control was happening.

It’s no wonder we turned lightning into gods. Seemingly out of nowhere, it could cut a tree in half, but vertically—far more impressive and quick work than any human could ever hope to do. It could start fires all on its own. People were sometimes even killed by lightning strikes.

Lighting and thunder would also tell you when a storm was on its way, acting as warnings to seek shelter. Perhaps the gods were kind some of the time, and they just wanted to give us a heads up before drenching us. Thoughtful!

Over the millennia, people contemplated what this force might be, and wondered whether there might be some way to explain it that didn’t invoke mythology. By the middle of the 18th century, a critical mass in our collective knowledge was approaching.

Ben Franklin was in the perfect position to think about this powerful and mysterious phenomenon. He knew that lightning had similarities with things we could observe down on the ground. Those same ancient ancestors who worshipped lightning also studied static electricity, which Thales of Miletus wrote about more than 2500 years ago.

Thales noticed that if you rubbed amber with fur, the amber became somehow attractive, and you could even pick up very light objects with the charged amber. This is why we call the stuff electricity today, by the way: the Greek word for amber was elektron.

Franklin knew that static electricity could make a spark and a crackle, just like lightning. He also knew of recent inventions that could produce sparks, and he had even built a few of his own so that he could experiment with this phenomenon himself.

There was even a Leyden jar. It could store static electricity and save it up for later, so you could create a much more powerful spark, not unlike a somewhat weaker lightning strike. Franklin played with these primitive batteries a lot.

The more he observed these up-close, on-the-ground phenomena, the more he began to think it was just the same thing as lightning. In order to gather more data, Franklin wanted to attract lightning from the sky by way of a lighting rod, an idea he concocted after observing that static electricity was easily stored among pointed metal.

America’s Prometheus snatched electrical fire from the sky with his lightning rod, and the current traveled down the wet string to a key Franklin had carefully set there, so he would see the spark when the lightning struck.

This was a moment of unification in physics that only comes around every so often. Like Einstein’s idea that space and time were part of the same phenomenon, or Newton’s understanding that the same force that held the moon in place also made apples fall to the ground, this new idea took time to spread and encountered plenty of resistance.

Ultimately, though, lightning came to be seen as yet another phenomenon we could seek to understand through careful observation and experimentation.

You can read a bit more about the story of how we came to understand electricity here next, if you’re so inclined:

Even today, there’s something about lightning that makes you stop in your tracks for a moment, isn’t there?

Inside a cloud, there’s a lot going on. Ultimately, a positive charge develops at the top of the cloud as negatively charged particles accumulate at the bottom. This creates a tension of sorts that we call voltage—technically, a difference in electrical potential.

Typically, air is an insulator, and it does a great job of keeping the electrical charge from flowing, but if this difference is great enough… kaboom! The air gets heated in an instant, exploding outward due to this expansionary force, and creating that bright streak of light we all know and fear.

The thunder results from the same rapid expansion, but we see the lightning long before we hear its twin. Here’s what I wrote about thunder:

When I wrote about thunder, I included an AC/DC song, so it seems only appropriate that I share a full Metallica album here. I present Ride the Lighting for your listening enjoyment:

What’s your most memorable experience involving lightning? Do you like one of Metallica’s first few albums better than this one? Did you ever play with static electricity as a kid (or as an adult)?