Aurora borealis forecast expands as strong solar storm hits Earth. Here’s what to know

A strong solar storm headed to Earth could produce colorful aurora displays across more U.S. states than usual Tuesday night.

The sun earlier this week burped out huge bursts of energy called coronal mass ejections, leading space weather forecasters to issue a geomagnetic storm watch.

Northern lights were forecast in Alaska, Washington, Oregon, Montana, North Dakota, South Dakota, Minnesota, Michigan, Wisconsin, Vermont, New Hampshire and Maine. Parts of northern Idaho, Wyoming, Nebraska, Iowa, Illinois, New York and Pennsylvania may also get a view.

The strength of the light show will depend on how Earth’s magnetic field interacts with the solar bursts, said Shawn Dahl at NOAA’s Space Weather Prediction Center.

Here’s what to know about auroras and how to spot them.

What are northern lights?

The sun is at the maximum phase of its 11-year activity cycle, making the light displays more common and widespread. Colorful northern lights have decorated night skies in unexpected places and space weather experts say there are more auroras still to come.

“This is going to kind of continue off and on throughout the year,” Dahl said.

Last spring, the strongest geomagnetic storm in two decades slammed Earth, producing light displays across the Northern Hemisphere. And last fall, a powerful solar storm dazzled skygazers far from the Arctic Circle when dancing lights appeared in unexpected places including Germany, the United Kingdom, New England and New York City.

Aurora displays known as the northern and southern lights are commonly visible near the poles, where charged particles from the sun interact with Earth’s atmosphere.

Skygazers are spotting the lights deeper into the United States and Europe because the sun is going through a major facelift. Every 11 years, its poles swap places, causing magnetic twists and tangles along the way.

Severe storms are capable of scrambling radio and GPS communications.

The sun’s active spurt is expected to last at least through the end of this year, though when solar activity will peak won’t be known until months after the fact, according to NASA and the U.S. National Oceanic and Atmospheric Administration.

What do solar storms do?

Solar storms can bring more than colorful lights to Earth.

When fast-moving particles and plasma slam into Earth’s magnetic field, they can temporarily disrupt the power grid. Space weather can also interfere with air traffic control radio and satellites in orbit.

In 1859, a severe solar storm triggered auroras as far south as Hawaii and caught telegraph lines on fire in a rare event. And a 1972 solar storm may have detonated magnetic U.S. sea mines off the coast of Vietnam.

Space weather experts aren’t able to predict a solar storm months in advance. Instead, they alert relevant parties to prepare in the days before a solar outburst hits Earth.

How to see auroras

Northern lights forecasts can be found on NOAA’s Space Weather Prediction Center website or an aurora forecasting app.

Consider aurora-watching in a quiet, dark area away from city lights. NASA’s Kelly Korreck recommended skygazing from a local or national park. And check the weather forecast because clouds can cover up the spectacle entirely.

Taking a picture with a smartphone camera may also reveal hints of the aurora that aren’t visible to the naked eye.

“Enjoy it,” said Korreck. “It’s this great show … from the sun to you.”

—Adithi Ramakrishnan, AP science writer

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