What was once a once-in-a-lifetime event—or a bucket-list trip to the Arctic Circle—has become a more common sight in recent years.

On Thursday evening, the breathtaking colors of the Northern Lights were once again visible to the naked eye across much of the United States.

Experts say the northern lights, or aurora borealis, are more visible right now because the sun has reached what astronomers call the “maximum” of its 11-year solar cycle.

This means that approximately every 11 years, at the peak of this cycle, the sun’s magnetic poles reverse and the sun goes from sluggish to active and stormy. On Earth, this would be as if the North and South Poles swapped places every ten years.

“In its calmest state, the sun is at solar minimum; “During solar maximum, the sun shines with bright flares and solar flares,” according to the US space agency NASA.

The current 11-year cycle, the 25th since records began in 1755, began in 2019 and is expected to peak next year.

As a result, the conditions that led to the recent activity will persist for many months to come.

The solar flares that caused the latest round of twinkling lights in the night sky began on October 8, when a giant sunspot erupted on the sun’s surface 150 million kilometers away.

The eruption sent a stream of electrically charged particles, called ions, to Earth. This current is known as the solar wind.

Auroras occur when the charged particles collide with gases in the Earth’s atmosphere around the magnetic poles.

When they collide, light is emitted in different wavelengths, creating colorful flashing and swirling light displays in the sky.

During this maximum moment in the solar cycle, the number of sunspots increases, resulting in more coronal mass ejections that send charged particles toward Earth, creating the aurora.

In the Northern Hemisphere, most of these activities occur near the Arctic Circle.

When there is strong solar activity, this can expand over a larger area.

Experts believe that given the overall high activity on the Sun, with many sunspots, there is a high probability that more of these coronal mass ejections will be directed at Earth in the coming months.

However, to get good visibility, make sure you are in a dark place – away from artificial light sources – and make sure you are in a region where the sky is clear of clouds.