Not every beautiful illumination in the sky is an aurora.
Skywatching enthusiasts are undoubtedly familiar with the mesmerizing aurora, the ethereal display of light waves that has fascinated humanity for centuries. However, there exists a phenomenon resembling the aurora, distinctively named "Steve" and "picket fence." While resembling auroras in appearance and behavior, Steve and picket fence phenomena are unique and not classified as traditional auroras. These captivating atmospheric events, often displaying stunning dancing waves of light, add an intriguing layer to the celestial wonders that enthusiasts can observe and study, offering a nuanced and fascinating aspect to the world of skywatching.
While auroras enthrall skywatchers with their dancing lights, another phenomenon mimics their beauty: Steve and the picket fence. This mysterious light show, though not an aurora, appears as a ribbon of purple and green alongside streaks of green light. Both Steve and the picket fence remain unexplained, adding to their allure and captivating scientists and skywatchers alike.
As per a release by the University of California, Berkeley, first recognized in 2018 as distinct from the common auroras, Steve-a tongue-in-cheek reference to the benign name given a scary hedge in a 2006 children's movie-and its associated picket fence were nevertheless thought to be caused by the same physical processes. But scientists were left scratching their heads about how these glowing emissions were produced.
Claire Gasque, a University of California, Berkeley, graduate student in physics, has now proposed a physical explanation for these phenomena that is totally different from the processes responsible for the well-known auroras. She has teamed up with researchers at the campus's Space Sciences Laboratory (SSL) to propose that NASA launch a rocket into the heart of the aurora to find out if she's correct.
Vibrant auroras and glowing phenomena such as Steve and the picket fence are becoming more common as the sun enters the active period of its 11-year cycle, and November was a good month for Steve observations in the northern latitudes. Because all these transient luminous phenomena are triggered by solar storms and coronal mass ejections from the sun, the approaching solar maximum is an ideal time to study rare events like Steve and the picket fence.
Mr Gasque described the physics behind the picket fence in a paper published last month in the journal Geophysical Research Letters and will discuss the results on December 14 in an invited talk at the American Geophysical Union meeting in San Francisco.