MEET STEVE

It looks like a ribbon of mauve light embroidered with green lost in the soft hair of a Celestial Goddess.  Meteorology is called Steve (Strong thermal emission velocity enhancemen), and is a rare atmospheric optical phenomenon that was discovered in 2015 by citizen scien scientists, the non-employees who, thanks to amateur observations and photos, immortalized this prodigy.  It looks like an aurora but its color, location and duration suggest it is not.  In fact, auroras are typical of the most extreme latitudes.  Typically, this phenomenon is associated with green streaks ′′ The Mysterious Green Streaks Below Steve ", placed below him. What is this?

 Come with uss and let's understand a little more.

 Auroras, like the aurora borealis, which I posted a few months ago, can be admired in the skies of the Nordic countries and are phenomena resulting from the interaction of charged particles from the sun with the Earth's magnetic field.  This phenomenon manifests itself near the magnetic poles.  Auroras, then, are characterized by a small number of very fast colored flashes.  On the contrary, atmospheric luminescences, even so-called airglow, are caused by chemical factors such as chemiuminescence, are present at all latitudes and are composed of quite constant glows, in terms of duration, in the sky.  Our dear Steve doesn't fit into either category.  Steve, in fact, can be seen at much lower latitudes than at auroras, from which he is also distinguished by a predominantly pink mauve color and for a shorter duration, about twenty minutes.  These are not atoms animated by electrons that come from the magnetosphere, as happens with auroras, but extremely hot particles that are linked to some as yet unknown phenomenon that affects the Earth's upper atmosphere.  It is believed that the violet colored ones are the result of ions moving at supersonic speed while the green streaks may be linked to movements that resemble vortices or gorges, such as those in rivers or other watercourses.  These vortices move more slowly than purple ones.  That would make you think of turbulence in space, a mixture of particles and a magnetic field called plasma.  The height of the mysterious green stripes occur is 100 to 110 km from the ground.

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Figure 1: Phenomenon called STEVE filmed in Copper Harbor in Michigan.  Credits: Marybeth Kiczenski