If the recent solar eclipse has motivated you to see more astronomical events, how about shifting to the nighttime to see the northern lights? The northern lights, also known as the aurora borealis, are an amazing natural light show visible at certain times of the year in the northern hemisphere.
"To figure out [the] northern lights you need three components — the sun, you need a magnetic field, and you need an atmosphere," notes Lake Effect Astronomy contributor and director of UWM's Manfred Olson Planetarium, Jean Creighton.
She explains that the northern lights are created when charged, moving particles from the sun speed into the Earth's magnetic field. The Earth has two magnetic poles that the particles are drawn to, "which is why this is considered a high latitude event, mostly," says Creighton.
These particles are then in the atmosphere of the Earth, "but even electrons don't like to be excited for too long ... so it ejects the excess energy it that has in the form of light and it goes down to it's basic level. That light that we see is aurora," she explains further.
Creighton says that the green, yellow, red, and blue hues of the northern lights tell us about the fundamental structure of elements in our atmosphere. "The energy that any of these things will provide in a situation where they get bombarded from particles from the sun is going to be different. You can think of it as a barcode," she explains. Oxygen's "barcode" is yellow-ish green and red, while nitrogen has a broader palette of colors like blues and purples.
However, just because they’re called the northern lights doesn't mean you can’t see them here in Wisconsin.
"Even if you go to Iceland, there's no guarantee that you're going to see northern lights. It depends on the weather and other things," says Creighton. "So, in your own backyard, we in Wisconsin have a better chance of seeing northern lights, considering our latitude. We're not particularly high, but from a magnetic, latitude point of view, we are higher."
To spot the northern lights, Creighton explains that you need to know how active the sun is and your own geomagnetic latitude. You can figure that out by visiting the National Atmospheric and Oceanic Administration's website and checking the K-index.
"For us [in Milwaukee], we need the K-index to be 6 and a half to see northern lights. Now if you're willing to drive north, not only do you get away from city lights which could block them out anyway, but the K-index needs to be lower for [the northern lights] to be visible higher in Wisconsin," she says.
For folks who can't travel to high-altitude spots like Iceland, Norway, Alaska, or Canada, Creighton and her team at the planetarium have made sure to have some resources to look at the northern lights in Wisconsin. "Come and see cool footage that I selected with my wonderful production students. Learn more details about how this works and how we use the normal website to figure out when would be a good time to see the northern lights anywhere you might be."
The Manfred Olson Planetarium will be hosting two programs on the northern lights on April 13 &20.
_
