When solar flares bound outwards from the Sun high - frequency images of them can sometimes look a little like a hand , with several lean streamers reaching upwards , known as a Flare Arcade . In television form flares show the blow , fingers of darkness curling down towards the Sun . Now uranologist think they have explained these “ down - moving dark voids ” as product of the unmixing of fluid of different density .
Once perhaps the bands of dark reaching menacingly towards our source of ignitor might have been key after a dark nobleman from a fantasy novel or some mythical light - vanquishing devil . Having only been discover in 1999 as extreme ultraviolet radiation and mild X - electron beam images of the Sun became available , however , they go by the more pedestrian namesupra - arcade downflows , although at least the acronym is SADs .
It ’s taken 23 years but uranologist have now offered up inNature Astronomyan explanation for SADs .
Almost as soon as SADs were seen astronomers had a hypothesis . Prior to solar flare , the Sun ’s magnetic discipline gets contort and condensed . Energy is released as the field reconfigures , causing the flares .
“ It ’s like stretching out a rubber band and nip it in the centre . It ’s stressed and stretched thinly , so it ’s going to snap back , ” saidDr Kathy Reevesof the Harvard & Smithsonian Center for Astrophysics in astatement .
The idea the SADs are a product of the snap back was an obvious one . The paper begins : “ Magnetic reconnection is a universal outgrowth that powers volatile energy - spillage consequence . ” Astronomers think something exchangeable , on a vastly more hefty scale , is responsible for thenewly discovered objectthat produce radio set wave like a hopeful pulsar , but orders of order of magnitude slower . However , the observation did n’t cope with the theory . or else of falling quick , as models suggested , SADs wave down slow .
The teemingness of data point produced by theSolar Dynamics Observatory , which take picture of the Sun every 12 instant at seven wavelengths , provide the peter require to solve the anomaly .
" Those dark , finger’s breadth - like nihility are in reality an absence seizure of plasma . The compactness is much lower there than the surrounding plasma , " Reeves explains . We have an mundane object lesson of what happens when fluids of different compactness combine when we adjudicate to mix oil and water - based liquids , for example olive petroleum and vinegar for a dressing . No matter how hard we stir them together , the two finally freestanding , but the process can be dull .
If this is indeed why SADs go on , it may not just be solar stargazer the explanation will make happy . The newspaper take the mental process “ A phenomenon correspondent to the shaping of similar structures in supernova remnants , ” so the work may aid explain these as well .
