In recent age skywatchers have been progressively fascinated by the phenomenon known as STEVE , ab initio think to be a type of aurora , but now agnize as being a sorting of cousin . However , all STEVEs have been spotted before midnight – and not just because that is when amateur are out postulate photographs . A mirror image is expected between midnight and dawn , but has only now been found in a previously overlooked picture from 2021 , with the help of the European Space Agency ’s Swarm satellites .
Theauroras of former Mayalerted more people than ever before to the wonders of space weather , thanks to phone tv camera , societal media and early alert . In late age , those same development have helped scientists learn that solar natural action actuate other sort of phenomenon high up in the atmosphere . These tend to pass off in affiliation with aurora , and can easily be confused with them , but involve different mechanism .
finicky interest has focused on what was originally calledSteve , now rebrandedStrong Thermal Emission Velocity Enhancement(STEVE ) . As we have fare to understand STEVE ’s causes , atmospherical physicist have concluded it should only be possible for STEVEs to hap before midnight , something tally in all observations . But does STEVE twist into a pumpkin at the witching hour , or is there a matching phenomenon before dawning ?
The first signs of the not-STEVE showed up an hour and a half after midnight local time, lasting about 30 minutes.Image Credit: Ramfjordmoen Research Station
A search to root that has revealed a serial of range of a function take on December 28 , 2021 from the Ramfjordmoen Research Station , Norway , as well as some less clean ones nine years before .
STEVEs arethought to be causedby stream of hot flatulency call sub - auroral ion drift ( SAID ) . These move westward in the evening towards the now lay out Sun . After midnight the move of the gun contrary , heading east in the direction of the future sunrise and is known as dawnside auroral polarization stream ( DAPS ) .
Both SAID and DAPS are triggered by solar coronal good deal ejection , just as auroras are , which is why they pass together . The question was whether DAPS are sufficient to trigger counter - STEVEs , or if there is an asymmetry that keep that occurring .
The path of the Swarm A and B satellites and the passage of electric charges they recorded.Image Credit: Nanjo, S., Hofstra, G.A., Shiokawa, K. et al./Earth, Planets and Space.
inexpert skywatcher are likely to head to their beds by midnight , particularly in polar regions where the dark are dusty . Many research camera still use black and blanched , making it hard to distinguish auroral super C from STEVE - similar purple – but the Ramfjordmoen all - sky photographic camera uses color , and does n’t quit .
Searching through archive of its observations , lensman Gabriel Arne Hofstra spot two set of images taken after midnight bear witness the STEVE ’s tell - tale mauve coloring , next to classic green . Still , claim to have distinguish a raw phenomenon ground on a smattering of photographs over two nights might trip the same response as a grainy range of a function purporting to be Bigfoot or the Loch Ness Monster . Hofstra and colleagues knew they needed evidence these coincided with an eastbound hot gas stream in the right location .
They checked the record of the European Space Agency ’s three Swarm satellites , launched in 2013 , and found two of them had been close enough to measure galvanic battlefield shape coinciding with the 2021 outcome . These reveal a current have by a speedy eastward ion current . The observed upshot differs from a STEVE in one way – it is closer to the pole than the true aurora , whereas STEVEs are at lower latitudes than coincident auroras . This makes the dawn phenomenon even harder to catch .
" As a scientist , collaborating with a photographer to uncover this new phenomenon has been a grand experience , ” pronounce Sota Nanjo of the University of Electro - Communications , Tokyo in astatement . “ Our findings not only open up new avenue in auroral physics , but also underscore the importance of uninterrupted collaborationism between scientists and photographer . Such efforts are peculiarly of the essence in the coming yr as solar body process come near its peak , when we may meet extraordinary phenomenon . ”
The arresting show of May 10 has almost for certain inspired more people to chase sky lights , and presumably not all will be quitting on the Elvis of 12 ( or even 1 am where daylight savings apply ) . In the process of photograph dayspring , some may conquer a abbreviated accompany majestic arc .
distinctly , we take a good name for this than counter - STEVE , however . EVE is the obvious choice , but might be too confusing for a sunrise phenomenon , even one first detected so close to Christmas . Perhaps we could really get on some people ’s nerves and call itADAM .
The findings are publish open access in the journalEarth , Planets and Space .
