The terrifying and awesome power of solar eclipses

Today, millions of people will gather to marvel at the total solar eclipse.

The awe that eclipses inspire is profound. “You suddenly feel as though you can see the clockwork of the solar system. Where you think you lived doesn’t look like the same place anymore,” Ernie Wright, who creates data visualizations and eclipse maps for

“We kind of know — in the back of our minds — that we live in a giant ball and it revolves around a hot ball of gas, and we’re floating in space. But you don’t really believe it until you see something like a total solar eclipse, where everything is all lined up and you go whoaaa.”

But that same power that inspires awe can also be seriously disruptive to — and sometimes scary for — life on Earth.

For some communities in the path of totality, tens of thousands of out-of-town eclipse-seekers are set to generate upward of $1 billion in revenue across numerous cities, from Austin, Texas, to Rochester, New York. Though lucrative, many places are girding for water shortages, sewage and garbage issues, and horrendous traffic.

The eclipse could also disrupt the US energy grid, threatening potential brownouts and blackouts in some areas of the country.

Solar eclipses aren’t just spectator events; they’re also an opportunity to study our solar system and our energy systems at home.

As my colleague Umair Irfan reports, the United States currently has more than 139 gigawatts of solar electricity generation capacity. That’s more than two and a half times the amount of solar that was on the grid during the last total eclipse in 2017. The upcoming eclipse will also shade a path twice as wide as the last one. Though much of the country will see some decline in solar power production, the biggest fall will be directly under the moon’s shadow.

For the most part, power grid operators aren’t too worried about outages or major problems during the eclipse. They saw this coming and planned for it. Unlike disruptions such as clouds, the moon passing between the Earth and the sun is easily predictable up to 1,000 years in advance.

Behind the scenes, though, it will require a carefully choreographed series of energy transactions to precisely ramp up electricity from a handful of generators and route it across hundreds of miles of transmission lines to millions of customers to precisely match the needs of every monitor, air conditioner, and light bulb the instant they turn on.

What they learn during this totality will prove useful as even more intermittent power sources connect to the grid. Power generators and transmission systems face even more severe stresses from rising energy demand and threats like wildfires, drought, and storms, many worsened by climate change.

Texas provides a good example: It has the second-largest solar capacity in the US and the path of the totality cuts straight through it. According to the National Renewable Energy Laboratory, the state is projected to see a nearly 60 gigawatt drop in solar power production when the eclipse passes over.

The Texas grid operator, ERCOT, has been running simulations and modeling how the eclipse will affect the state’s power network, which, unlike the rest of the continental US, has few connections to other states. That means it can’t easily buy or sell electricity across state lines if it has too much or (in this case) too little power.

But for an ordinary power user — someone like you — it’s unlikely you’ll notice anything about your electricity during the eclipse. Some utilities might have to scramble to secure extra power, but that won’t manifest at the outlet.

Phew.

Eclipses are a rare moment to observe the solar corona, the sun’s outer atmosphere that can be observed radiating from the eclipsed sun’s outer edges, and the dynamic of solar weather, which can wreak havoc on life on Earth. Radiation from solar storms often ends up hitting the planet, which can lead to beautiful phenomena like the northern lights. But it can also cause massive problems, like energy grid disruptions, major blackouts, or even taking down satellites.

Despite how much damage solar storms can do to our tech on Earth, scientists are still struggling to predict them. And that’s because they don’t understand everything about how the corona works. Even though it extends far out from the surface of the sun into freezing cold space, the corona is still a million degrees hotter than the surface of the sun. And scientists aren’t sure why.

This is why Shadia Habbal, a professor of solar physics at the University of Hawaii, became an eclipse chaser.

“We have some clues [about solar storms],” Habbal told Noam Hassenfeld on a recent episode of Vox’s Unexplainable. “We know what’s causing them, but we can’t predict when they will happen. And that’s one of the things we’re trying to gather: some more information from our eclipse observations.”

A total solar eclipse happens somewhere in the world about every 18 months. The next one will be on August 12, 2026, and it will pass over Spain, Iceland, and Greenland. The one after that? August 2, 2027, over North Africa.

NASA keeps a catalog of all the eclipses (both solar and lunar) that have occurred or will occur from 1999 BCE to 3000 CE. Check that calendar and you’ll see that the next solar eclipse over the United States will be visible in Alaska in 2033. For the lower 48? 2045.

See you then.

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