Get To Know ‘Steve’: What Satellite Data Say About Strange Purple Streak Of Light In The Night Sky


People chasing the northern lights have discovered a new feature recently — a ribbon of purple light which scientists call Steve — and nobody knew what it was or how it had occurred. ESA's swarm magnetic field mission has now met Steve and is helping get a better understanding of it.

Since an amateur group of Alberta sky watchers started documenting the unusual atmospheric phenomenon that sometimes occurs in northern lights, astronomers have taken notice of Steve's existence.

Meet Steve: Satellite Data Describes The Purple Ribbon

Auroras are undeniable proof of our planet's electrical connectivity to the Sun. The better we understand the phenomenon of auroras in general, the more easily we could describe Earth's magnetic field, along with the atomic particles that stream from the Sun as solar wind.

During a recent Swarm science meeting in Canada, Professor Eric Donovan from the University of Calgary explained why this highly photogenic phenomenon couldn't have occurred two decades in the past, back when people had started studying the aurora.

Steve appears as a long, breathtaking purple streak that occasionally shows itself in the middle of an aurora.

Chris Ratzlaff, a professional photographer, is also the administrator of a Facebook group called "Alberta Aurora Watchers," a place with roughly 8,000 members. According to Ratzlaff, Steve was first believed to be a proton arc, which turned out to be an incorrect hypothesis, as such a phenomenon wouldn't be visible to the human eye.

"The ground network and the electric and magnetic field measurements made by Swarm are great tools that can be used to better understand Steve. This is a nice example of society for science," noted Donovan.

Data from the electric field instrument showed some obvious changes, which could help better understand the phenomenon at hand. As the temperature approximately 200 miles above our planet's surface jumped by 5,500 degrees Fahrenheit, the data showed a wide ribbon gas, which is approximately 15.5 miles in diameter.

Steve seems to be approximately 10 to 20 degrees in latitude closer to the equator compared to the normal overhead location of the aurora, and its position implies that it could be overhead at latitudes comparable to Calgary, Canada. The phenomenon has the visual form of a narrow, elongated arc over the sky, aligned East-West and that expands for hundreds or even thousands of miles.

Steve's color is purple. While it may seem faint, it can be photographed with five to 10-second exposure, and it can last for over 20 minutes.

Satellite Tools Provide Real-Time Data About The Auroras

While the phenomenon is not uncommon, scientific tools have never captured it before. The community of amateur observers is the one that alerted the scientific community, which is something that hardly could have happened in the past, when people lacked the tools to observe such phenomena.

Now that it has been spotted, details from Swarm and a series of other tools will work on establishing the source of this beautiful occurrence.

Among the tools that can monitor Steve's evolution is Aurorasaurus, a crowd-funded project that shows a map of the auroras in occurring in the world — in real-time view. This way, a wide array of people, from observers to scientists, can track down the phenomenon and find out more data about its whereabouts.

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