Today's USRA's Earth Science Photo of the Day (EPOD) is from...us!

We are so glad to be able to contribute to the Universities Space Research Association's Earth Science Photo of the Day.

Photographers: Tim Erskine; Holly Erskine

Summary Authors: Holly Erskine; Tim Erskine

The eye-catching northern lights featured above were captured from Sister Bay, Wisconsin in March and April of 2023. The bottom photo was taken on March 23, 2023. This auroral event was more energetic than April’s aurora, on April 23, 2023. A third photo (top) shows my husband, Tim, with his camera and tripod observing the March 23 event.

Because we live just a few miles from an official International Dark Sky Park, Newport State Park, Wisconsin, we're afforded wondrous views of the night sky and on occasion the northern lights. Note that on the top photo (March 23) you can detect both Orion and the Pleiades. On the middle photo (April 23), the waxing crescent Moon is setting over the waters of Green Bay.

Sister Bay, Wisconsin Coordinates: 45.1872, -87.1209

Newport State Park, Wisconsin Coordinates: 45.2411, -86.9916

Related Links:

Aurora Observed over Northern Michigan

Night Sky Ventures, Inc.

How to see an aurora

It helps to have an App that will notify you when our sun does a big burp of particles. It also helps to have a friend with that App text you when  you ignore that notification. (Thank you Kent Moraga, without which my March photos would not exist.) Or you can just check Space Weather online.

It helps to be further north (for the northern lights or aurora borealis) or south (for the southern lights or aurora australis). However, I've seen the northern lights as far south as Tooele, Utah, and I've met people who have seen more energetic displays further from the poles as well.

I would not have known I was seeing my first rather weak aurora, except that I was with more experienced astronomers who were confident that's what it was. For my first very weak aurora which was in the mid 1990's, I had to use my peripheral vision (see below in tips), and only then did I see a very dynamic white light jumping up and down the northern horizon. I was surprised by how rapidly it moved, like a searchlight, except that it was definitely not a searchlight originating from any particular place. Even for the more dramatic aurorae I've seen after that, I could not detect color with my eyes, I only saw white light racing in curtains and streaks and rays across the sky.

Here's some tips:

1. Get away from light pollution. That's the most important thing.
2. Shield your eyes from any lights. If you must use light, use red lights, which won't blind your retinas to fainter light.
3. Get as far north (or south for the southern lights) as you can and look north (or south)
4. No equipment needed; but a camera will pick up colors you can't detect with your eyes
5. As with a lot of astronomy, you may want to use your peripheral or averted vision. The sides of your retinas have more rods, less cones. Cones are sensitive to color while rods see black and white. You can't see color so well at night so you want to use your rods on the sides of your eyes. This averted vision trick is essential for doing a lot of amateur astronomy and takes some getting used to. What to see something faint in the sky? Don't look directly at it!
6. Don't expect to see color. You might only see white light bands of light rising and falling. If you can take a picture, your photos may reveal the color your eye can't perceive.

For the March 23, 2023 aurora, I was lucky enough to get a message from a friend about what was going on.

For the April 23, 2023 aurora, my husband Tim is half asleep and I am the night owl up in bed reading as usual, and I see a Chicago news story that says "Controlled mass ejection from the sun." That headline cracks me up.

I'm pretty sure the sun doesn't control any of its particle burps. It's coronal mass ejection, folks, not controlled. Note to journalists: control your auto-fill error correction ejections. My old science teacher self is smug. I have to tell Tim about the silly headline.

But Tim has only one response for me. "Go see if there is an aurora," he commands.

"I don't want to," I say, all cozy and warm and not wanting to get up. It's midnight.

Well, I did, there was, and an hour later we are trying to unfreeze ourselves from standing taking pictures on our balcony.

 

fun aurora facts

Charged particles, (mostly ordinary electrons and protons that you would find in your basic atom) from the sun get caught in Earth's magnetic field lines. This ionizes some gases in our atmosphere, which then emit light.

 

Different gases produce different colors of light as fingerprints. This isn't as straight-forward as saying that oxygen or nitrogen is red or green, because gases come in different forms: atomic, molecular, ionized, plus depending on how hard they are hit, the same species can emit one or more different wavelengths.

Green (most common color to see): monotomic oxygen (O)

Red: Monotomic oxygen (O)  and diatomic nitrogen (N2)

Blue: ionized diatomic nitrogen (N2+)

Purple and blue (hard to see against the sky): hydrogen molecule (H2) or helium atoms (He)

 

 

Auroras on Jupiter, Saturn, Uranus, and Neptune have been observed. It was once thought a magnetosphere was required for for a planet to have an aurora, except that Mars, which doesn't have a magnetic field, does have a version of aurora as well.

 

The sun goes through an eleven-year cycle of activity. The last solar max was 2014, the next solar maximum will be 2025.