Always wanted to see the Northern Lights? You can do this in Idaho. Here’s when, how to watch

From time to time, an intense burst of radiation is expelled from the sun’s atmosphere toward space. The flare will contain the energy of a billion hydrogen bombs, shooting billions of subatomic particles called protons and electrons toward Earth.

The massive solar ejection can impact Mercury, damaging its exosphere and stripping material from its surface. The flare could then hit Venus, knocking ions out of the planet’s gravity and weakening the atmosphere.

Next, when Earth’s orbit is in the right place at the right time, the solar flare will smash the planet… and cause pretty lights in the sky.

These are known as the Northern Lights or Aurora Borealis and occur around the Earth’s North Pole. A similar phenomenon called the southern lights or aurora australis also occurs around the South Pole.

And sometimes you can see the Northern Lights in Idaho.

What exactly are the Northern Lights?

When pretty colored lights appear randomly in the sky, there’s usually some strange science afoot.

But in its simplest form, the Northern Lights are formed because the magnetically charged protons and electrons collide with Earth’s magnetic field, which shields the planet from cosmic rays and particles emitted by the sun. The protons and electrons follow the magnetic field, which meets at the north and south poles.

That’s when the magic happens.

“When[protons and electrons]hit the atmosphere, they excite the atoms there, and oxygen glows green,” Jason Barnes, a professor in the University of Idaho’s Department of Physics, told the Idaho Statesman in a phone interview. “And so a lot of what you’re seeing is glowing oxygen in the upper atmosphere.”

Barnes hasn’t worked directly with Earth’s Aurora Borealis, but he has worked extensively with the Cassini spacecraft to observe a similar phenomenon on Saturn.

Barnes also explained that oxygen is not the only molecule whose atoms are excited by solar flares, but that it is the most dominant molecule in the atmosphere and the one we can most easily see with our eyes.

How often do the Northern Lights appear?

The Northern Lights are always present near the poles because protons and electrons from the sun are constantly hitting the earth.

But the large solar flares can cause the lights to appear as far away as the continental United States at times.

“If the solar wind is stronger and throws more material into space, it will sort of overwhelm the Earth’s magnetic field,” Barnes said. “And that will cause the latitude of the aurora to drop to lower and lower latitudes.”

Astronomers and physicists predict how far south the aurora borealis might travel by measuring the strength of the solar winds with a reading called the K-index. The K-Index typically stays below a reading of 4, Barnes said, which would mean the Northern Lights aren’t venturing too far south.

But when the K-Index starts measuring above six, there’s a chance for the people of Idaho to see the sky light up above them.

The Sun goes through an 11-year sunspot cycle, oscillating between having lots of sunspots on its surface and then having almost none – sunspots causing major solar flares.

“Right now we’re in mid-solar maximum upswing, so there’s a lot of solar activity these days,” Barnes said. “Therefore, there’s a much greater chance of having one of those high K-Index indices that would allow Aurora to get this far south today than there was three or four years ago.” And similarly in five or six years.”

How to see the Northern Lights in Idaho

In Barnes’ words, the Aurora doesn’t care what time of year it is: “It’ll just do its thing.”

But there are ideal conditions for observing them. It gets dark much earlier in the winter, meaning viewers don’t have to stay out as long to try and catch them. But winter also usually has a higher chance of clouds, meaning summer viewing is best when skies are clear.

Barnes also recommends a spot away from light pollution, but says he saw the lights in Idaho around the city of Moscow. He also said the Central Idaho Dark Sky Reserve would be a good spot — the reserve is just 10 minutes northeast of the east shore of Pettit Lake and boasts some of the darkest skies in the United States.

Once you’re in a dark place, the next challenge is to identify the lights.

“It looks like a thin cloud. But it’s changing really fast. So it’s changing on timescales of maybe 20 or 30 seconds,” Barnes said. “And that’s really the big clue that you’re looking at an aurora and not just a random cloud.”

Auroras can be viewed with the naked eye. Barnes advises against using telescopes or binoculars because auroras are a long-range event and a magnifying device can limit your view.

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