STEVE may not be whoyou think he is . Or , rather , what you intend it is .
Not too long ago , professional aficionados of the Nox sky were thrilled to take a closer expression at something inexpert night sky watcher had been seeing for decades . This curious luminous filament , one that danced a slight differently from the rest of the aurora , was on the side named the Strong Thermal Emission Velocity Enhancement ( STEVE ) in apaperback in March of this year .
It was not definitively term an aurora by the team at the meter , but it seemed probable it was a new type of aurora . According to new research , feature some of the authors of that same paper , STEVE front to be an role player . It ’s in fact not clear what STEVE is at all , which means there ’s a secret up there that we are n’t close to lick just yet .
The Northern ( borealis ) or Southern ( australis ) Lights were once often opine of asancestral spiritsdancing in the sky , or perhaps a bridge circuit to a deific dimension . Today , we know that they form when particle launch from the Sun are dragged down by our planet ’s magnetic field line , which are concentrated around themagnetic pole .
As they come up against our atmosphere , they collide with atoms within it . They become energetically excited , which kick up their negatron to higher - energy plate . As energy is lost , their electron fall down to lower energy levels , and they emit light : immature for oxygen , reds and blues for nitrogen .
If you are standing in the Northern Hemisphere , somewhere well dark and without moonlight , you may have recognize a purple sliver of light just south of the main upshot – north of it , if you ’re in the Southern Hemisphere . It certainly looked like part of the aurora , but its segregation struck skygazers as singular .
It was leave the backronym STEVE . This hint at what it might be , but without giving the printing that its strong-arm properties were only interpret .
An aurora , seen from Ontario , Canada , possibly feature STEVE.Northern Lights Graffiti / Flickr ; CC BY 2.0
Passing it on to several NASA sunrise researcher , it was find that STEVE was tie in with a clear-cut current of industrious particles , one know as a subauroral ion drift , or SAID . SAIDs were known about before , and were see to it to occur more commonly in give and drop , which matches when STEVE was most commonly abide by .
It seemed , then , that STEVE was a visualisation of a SAID , possibly making it an aurora . This was n’t a smoking hit man , though – it was correlative evidence . It was justassociatedwith the aurora , with the lineal cause - and - impression relationship related to STEVE remaining enigmatical .
This newGeophysical Research Lettersstudy analyse a 2008 STEVE result using a internet of ground- and planet - based gumptious speck detector . They find that no charge particles were pouring into the ionosphere , the sliver of atmosphere in which the dawning are forged , during that special event .
The team conclude , then , that it was “ clearly distinct from the aurora ” and instead name to it as a skyglow , a diffuse light source in the sky whose origins persist strange – perhaps a snatch odd , as STEVE tends to have a filamentous social structure .
STEVE may not be hangdog of humbug just yet . This analysis is based off a single STEVE case , so it ’d be interesting to see how others equate , as the researcher themselves underscore in their study .
The paper also includes some interesting caveats . Protons and high - free energy negatron were n’t observed , and although an electron zip outpouring was find , it was too low - energy to be responsible for for auroral generation . The source do mention , however , that they “ can not rule out the hypothesis that STEVE might be colligate with low?energy proton precipitation ” – aprocessthat can generate sunup .
They refer a few other possibilities for STEVE ’s genesis , but they ca n’t yet narrate where it is even appear : the dawn - filledionosphere , or elsewhere . The squad certainlydon’t thinkit ’s an aurora , but they ca n’t be absolutely sure just yet . As before , no one knows why it ’s purple .
STEVE is certainly something , but in good order now , it ’s an astrophysical question stain .
