Solar storm surprises, kicks off full week of skywatching

Tuesday, May 10, 2016, 1:08 PM - International Astronomy Week is off to an amazing start. Not only was there Monday's transit of Mercury, but a surprise Mother's Day solar storm kicked things off in a spectacular way.

Over the weekend, just as astronomers - both professional and amateur alike - across country were gearing up for this week, Earth and the Sun had a little treat in store. Even as early as Friday evening, it became clear that Earth's geomagnetic field was going to be quite active over the weekend, as the planet was set to encounter a region of the Sun's solar wind known as a Coronal Hole High Speed Stream (CH HSS).

While the mechanics of this are quite fascinating (and read on to discover more), the results of it are the truly spectacular part:

Aurora from Chapleau, ON on May 7, 2016. Credit: Kari Luhtasaari

Arching aurora seen from Red Deer, AB on May 7, 2016. Credit: Shannon Prentice

◀ {Angry Dragon 🐉} ▶ •••••••••••••••••••••••••••••••••••••••••••••• 📌 Location: Tofield, Alberta •••••••••••••••••••••••••••••••••••••••••••••• An absolutely incredible Aurora Borealis display last night, with displays reaching Kp7 on the 0-9 Kp index at times. This corona perspective looks like a Dragon to me, what do you see? If you happened to catch the Aurora where you were last night, don't forget to tag your shots #worldaurora, for a chance to be featured on @worldaurora. •••••••••••••••••••••••••••••••••••••••••••••• ======================================= #bestnatureshot #nightphotography #ipanightphotography #totescanadian #canadiancreatives #nature_sultans #ptk_sky #main_vision #hubs_united #jaw_dropping_shots #majestic_earth #special_shots #ig_all_americas #ig_myshot #ig_yeg #itsamazingoutthere #ourplanetdaily #worldwide_reverie #earthtelligence #mustbeedmonton #nature_perfection #skymasters_family #supreme_nightshots #lexarmemory #igworldclub #infinity_shotz #cool_capture_ #amazing_longexpo #fs_longexpo

A photo posted by Mark Jinks (@splitsecondsnapshot) on May 8, 2016 at 5:17am PDT

The absolute highlight of the trip for me was sipping whiskey while watching the Northern Lights from the top of The Crack, on the La Cloche Silhouette Trail. First time seeing them so vibrant!! What a way to end the trip! • Killarney Provincial Park

A photo posted by @trail_bound on May 9, 2016 at 3:24pm PDT

TheGetaway

A photo posted by Chris Malloy (@mistermalloy) on May 9, 2016 at 7:08am PDT

Coronal Hole High Speed Stream?

As for what was going on in space that caused this amazing display of the auroras, it was due to the solar wind, specifically a ribbon of solar matter that was streaming at high speed out of a large hole in the Sun's corona.

Credit: NOAA SWPC/NASA SDO

Matter is always streaming away from the Sun, creating ribbons that trail behind the Sun's rotation as the stuff spreads out into space. These ribbons are divided into two types - ones that are packed with slower moving particles, with an overall magnetic field that point roughly in the same direction as Earth's magnetic field ("positive polarity"), and ones that are thinly populated with faster moving particles, with a magnetic field pointing roughly in the opposite direction as Earth's magnetic field ("negative polarity").

NOAA SWPC/S. Sutherland

When a high density/low speed, positive polarity stream sweeps past Earth, the similar-direction magnetic fields repulse each other, and the majority of the particles are simply diverted around the planet. When a low density/high speed, negative polarity stream sweeps past Earth, the opposite magnetic fields connect, allowing many of these fast-moving particles to stream down into the atmosphere near the poles. These high-energy particles smack into air molecules, causing them to glow in the eerie colours of the auroras.

A coronal hole high speed stream is similar to the negative polarity streams, but with more particles in the stream. Thus, they tend to be responsible for some strong displays of the auroras - even as strong as what we can see from the massive solar eruptions known as coronal mas ejections.

To see these events, the best place to go is somewhere dark, outside major sources of urban light pollution. Find somewhere comfortable, without any direct sources of light in your field of view, and allow your eyes roughly 30 minutes to adjust to the dark.

If you're interested in photographing the auroras, Theresa and Darlene, of Team Tanner, have some tips below:

Sources: NOAA SWPC

Watch more views of the aurora below