Environment & Outdoors

Smiling man next to a large home telescope

After a little break (of 25 years or so) Bob King is celebrating his retirement with a return to The North 103.3's airwaves!After almost 40 years with the Duluth News Tribune, Bob is now retired. But scratch a print guy and you'll find a radio guy; King and then-UMD Planetarium Director Glen Langhorst hosted Startalk on KUMD for several years in the early '90s.Listen for Astro Bob every other Tuesday at 8am on Northland Morning.

Astro Bob's Backyard Astronomy: "It must have been airglow..."*

The North 103.3

Published May 31, 2022 at 12:50 PM CDT

Streamers of green airglow cover much of the sky in this photo taken around 11:30 p.m. on May 30 near Barnum, Minnesota. Bob King writes, "Airglow is created when ultraviolet light from the sun breaks apart oxygen and nitrogen molecules in the upper atmosphere during the day. At night, they recombine and release energy in the form of green or pink light. The multiple layers or ripples of airglow were likely caused by the strong thunderstorms passing through the area. Thunderstorms can create gravity waves that ripple the upper atmosphere like a rock thrown into a pond."

Though a major storm swept across the Northland last night, Bob King headed south toward Barnum where he found a patch of open sky. In the next couple hours, there was a lot happening (besides the very abundant, very vocal frog population surrounding him).

Though not as numerous as some astronomers were hoping it would be, the Tau Herculids meteor shower did appear, and Bob was able to capture some photographs. Here is one:

A Tau Herculid meteor (center, left) streaks across the southwestern sky late on May 30 from near Barnum, Minnesota. The shower, spawned by fragments of Comet 73P/Schwassmann-Wachmann, occurred as predicted but didn't reach the "storm" level — at least visually.

He also witnessed a lovely display of airglow (see the photo at the top of this article, and its caption).
Coming up in June, around the summer solstice, see if you can spot noctilucent clouds in the evening twilight. Bob writes, “The clouds form on meteoric dust about 50 miles high. They're Earth's highest clouds and appear low in the northern sky starting about 45 minutes to an hour after sunset (and before sunrise) during summer evenings. June is the best month to spot them.”

Eerie, blue noctilucent clouds reflect in a small lake near Duluth, Minnesota, on June 27, 2021, around 10:30 p.m.