Did you know that Aurora has a boyfriend? And his name is Steve? I didn't know it either, but thanks to @terrylovejoy I found out last week and decided to do some searching of my own on this "colorful" guy.

Image from: pixabay.com

Aurora is a showgirl. What she does is dance over the sky in colorful veils of photons, leaving her audience stare in awe and amazement. Ok, in the physics books we learn that the aurora phenomenon is caused when charged particles leave the sun and travel in space (solar wind). On their way, some of them interact with the Earth's magnetic field, collide with the molecules of the atmosphere and excite them in order to release a colored photon. All these photons combine to paint a beautiful picture over the night sky of the North and South poles. I still believe Aurora is a dancer of the seven veils (like another Salome) and she has a lovely partner to follow her lead.

Ladies and gentlemen, meet...

STEVE!

Steve is a cool guy. He works in the sky show business just like his girlfriend (that's where he met her). Although he is not as talented and impressive as his girl, Aurora, Steve still knows how to put on a great show! What he does? Well, he keeps our eyes pinned on him with his beautiful purple colors and dance moves.

Image from: wikipedia.org - Author: - Elfiehall - License: CC BY-SA 4.0

Talk science to me

What? Don't you believe my version of the story? Pfff! Ok, Doubting Thomas, here is what scientists, the bearers of official knowledge, have to say about Steve:

When the typical auroras appear like veils of green or yellow, with some purple or pink; Steve is more like streaks of purple and some occasional green. Steve got his name at random before he was studied and after scientists began to get a grip of what this phenomenon might be, his name had to be "adjusted" into an acronym for "Strong Thermal Emission Velocity Enhancement". [3, 7]

A phenomenon that hasn't occurred but was observed recently (2015-'16), STEVE is a wide (25 km) strip of hot gases running at speeds of 6 km/sec. Observed by citizen scientists, who have contributed greatly into the studying of the phenomenon, Steve was originally (and mistakenly) believed to be a proton arc (a type of sub-auroral arc - with an auroral arc being a wide, luminous strip moving westwards) that is usually subvisual and wide and appears in higher latitudes than this one did. [3, 4]

Over a few years of observations and photographs, a pattern seemed to have been formed regarding Steve's appearance. Steve would "come on stage" at nights with strong auroral activity or substorms or geomagnetic storms, as this is the time when the aurora ovals expand from the poles towards the equator. Steve, though, was seen in unusually lower latitudes (65-80°). This year (2018)  he was visible in North America (Alaska, Canada and U.S. states of the North), the UK in Europe and New Zealand.  [3, 4, 5]

Steve was eventually thought to be some kind of SAID (SubAuroral Ion Drift - currents of ions moving at higher latitudes), it portrayed the density depletion, the characteristic strong flow of ionized particles (it was moving at speeds of almost 6 km/sec) and it also had the extremely high temperatures of 6000°C. Given the fact that SAID's cannot be visually perceived like Steve, who was also hotter and moving faster than a typical SAID; it was a unique version of an ion drift, that needed to be looked into deeper. [3, 4]

Image from the Public Domain through: flickr.com

Steve is a good (lay)man

The "discovery" and further studying of this not-fully-understood phenomenon has highlighted the importance of citizen scientists and their contribution to the scientific field. The first reports on Steve started to appear in forums and the aurorasaurus.org (a project funded by NASA where citizen scientists contribute with their observations and photographs) in 2015-'16. Ever since there has been a world-wide collaboration in order to learn more about him and understand how the Earth's magnetic field interacts with space ions. [6]

Steve was also observed from space. One of the Swarm satellites provided data that were crisscrossed with the citizen scientists reports. Scientists managed to match the ground sightings with the measurements from their  electric field instruments and saw that something peculiar was happening, something that had been there for long, but they could see it just now. [2]

Without all those amateur astrophotographers and astronomers, we wouldn't have had such a rich archive and Steve might probably still be... an unknown dancer with a wasted talent.

Here is a video summary by National Geographic

References

[1] esa.int/Getting_to_know_Steve
[2] esa.int/When_Swarm_met_Steve
[3] advances.sciencemag.org
[4] nationalgeographic.com
[5] wikipedia.org
[6] nasa.gov
[7] sciencemag.org

In case you want to freshen up your knowledge on the Aurora phenomenon, have a look at this post: Bizarre Natural Phenomena Vol.28 - A Colorful Canvas On A Night Sky (Aurora Borealis)

Thank you so much for your time!

Until my next post,
Steem on and keep smiling, people!