Swarm explores a new feature of the northern lights

April 21, 2017
Thanks to scientists, citizen scientists, ground-based imagers and ESA’s magnetic field Swarm mission, this purple streak of light in the night sky has been discovered. Originally thought to be a ‘proton arc’, this strange feature has been called Steve. While there is still a lot to learn about Steve, the electric field instrument carried on the Swarm mission has measured it. Flying through Steve, the temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westward at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon. Credit: Dave Markel Photography

Thanks to social media and the power of citizen scientists chasing the northern lights, a new feature was discovered recently. Nobody knew what this strange ribbon of purple light was, so … it was called Steve.

ESA's Swarm magnetic field mission has now also met Steve and is helping to understand the nature of this new-found feature.

Speaking at the recent Swarm science meeting in Canada, Eric Donovan from the University of Calgary explained how this new finding couldn't have happened 20 years ago when he started to study the aurora.

While the shimmering, eerie, light display of auroras might be beautiful and captivating, they are also a visual reminder that Earth is connected electrically to the Sun. A better understanding of the aurora helps to understand more about the relationship between Earth's magnetic field and the charged atomic particles streaming from the Sun as the solar wind.

"In 1997 we had just one all-sky imager in North America to observe the from the ground," said Prof. Donovan.

"Back then we would be lucky if we got one photograph a night of the aurora taken from the ground that coincides with an observation from a satellite. Now we have many more all-sky imagers and satellite missions like Swarm so we get more than 100 a night."

Today’s wealth of all-sky imagers in North America and satellites to observe the aurora borealis is a far cry from 20 years ago. Credit: University of Calgary

And now, social media and citizen scientists also have an increasingly important role.

For instance, the Aurorasaurus website makes it possible for a large number of people to communicate about the aurora borealis. It connects citizen scientists to scientists and trawls Twitter feeds for instances of the word 'aurora'. In doing so, it does an excellent job of forecasting where the aurora oval will be.

At a recent talk, Prof. Donovan met members of another group on Facebook: the Alberta Aurora Chasers. The group attracts members of the general public who are interested in the night sky and includes some talented photographers.

Looking at their photographs, Prof. Donovan came across something he hadn't seen before. The group called this strange purple streak of light in the captured in their photographs a 'proton arc' but for a number of reasons, including the fact that proton are never visible, he knew this had to be something else.

However, nobody knew what it actually was so they decided to put a name to this mystery feature: they called it Steve.

While the Aurora Chasers combed through their photos and kept an eye out for the next appearances of Steve, Prof. Donovan and colleagues turned to data from the Swarm mission and his network of all-sky cameras.

The aurora borealis is a visible display of electrically charged atomic particles from the Sun interacting with Earth’s magnetic field. Credit: Sherwin Calaluan

Soon he was able to match a ground sighting of Steve to an overpass of one of the three Swarm satellites.

Prof. Donovan said, "As the satellite flew straight though Steve, data from the electric field instrument showed very clear changes.

"The temperature 300 km above Earth's surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westwards at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon.

"It turns out that Steve is actually remarkably common, but we hadn't noticed it before. It's thanks to ground-based observations, satellites, today's explosion of access to data and an army of joining forces to document it.

"Swarm allows us to measure it and I'm sure will continue to help resolve some unanswered questions."

ESA's Swarm mission scientist, Roger Haagmans, added, "It is amazing how a beautiful natural phenomenon, seen by observant citizens, can trigger scientists' curiosity.

"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."

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9 comments

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ursiny33
not rated yet Apr 21, 2017
Its manufacturing new hydrogen atoms in this zone from trapped protons in the earths magnetic field perimeter ,
cantdrive85
1 / 5 (3) Apr 22, 2017
The group called this strange purple streak of light in the night sky captured in their photographs a 'proton arc' but for a number of reasons, including the fact that proton aurora are never visible, he knew this had to be something else.
However, nobody knew what it actually was so they decided to put a name to this mystery feature: they called it Steve.

Face, meet palm....

Da Schneib
5 / 5 (3) Apr 22, 2017
As astronomical instruments become more available to the general public, and knowledge of experimental procedures spreads as well, meticulous and therefore valuable observations of astrophysical phenomena become more available for scientists to evaluate, and new phenomena are not only observed but analyzed. Nobody with an enormously expensive observatory is looking for Steve, and in fact an enormously expensive observatory is not what is required.
Chris_Reeve
1 / 5 (4) Apr 22, 2017
The immediate environment surrounding the Earth has proven far more complex than anybody would have guessed a hundred years ago. It is filled with all sorts of electromagnetic structures like this. But, the scientific community has so far failed to draw many connections between what is happening down here on the surface and this surprising activity just above our heads.

That may prove to be a huge mistake. Take for example this discovery ...

https://watchers....-season/

... that Birkeland currents are quite a bit stronger at the north pole than the south.

This is quite a remarkable discovery, for as anybody who has watched Mr Wizard will recall, electricity can heat things up. In the Earth sciences, it goes by the name of electric joule heating -- and we'd be wise to consider on "Earth Day" that this asymmetry in the electric currents can cause an asymmetry in polar heating.
FineStructureConstant
3.8 / 5 (10) Apr 23, 2017
...it goes by the name of electric joule heating
Hey - I just checked my electric joule this morning, and it definitely feels warmer than yesterday! I'm booking a flight to Antarctica while I still can !!!
HannesAlfven
1 / 5 (4) Apr 23, 2017
Not only do we see hotspots which correspond to electrical currents at the poles of some planets -- Enceladus being the best example -- but it's further worth noting that Venus has a polar vortex which is also known to split.

It should be apparent that since climate specialists are not trained in plasma physics that -- by their own reasoning -- they would not be the best judge of whether or not such things can matter for their own models.

It's yet more worth mentioning that it's not properly understood what happens to those charged particles once they enter into the atmosphere/ionosphere. This science is ongoing. What we DO know is that the electrical phenomena cannot even be represented with general circulation models because they are BOTH too small and too transient to even show up in such models.
jonesdave
5 / 5 (7) Apr 24, 2017


It should be apparent that since climate specialists are not trained in plasma physics


Jesus. Coming from a member of a cult who have nobody trained in plasma physics, and believe in Velikovskian woo! Irony, much? The heating, you idiot, is 300 frigging kilometres above the Earth. That's nearly as high as the ISS. How are you proposing that this heat reaches the ground? Are there studies to show ground temperature increases associated with these phenomena? Or temperature spikes due to strong auroral activity? No, of course not. Because they don't happen. Lern to scienz.
RealityCheck
1 / 5 (2) Apr 24, 2017
@Chris_Reeve.

The example of Mercury (planet) having no atmosphere to speak of, and hence unable to 'lag' against the heat loss back to space from whatever amount of heat input by the Sun's activity, tells that Earth's atmosphere is what determines the NET state of global average heat retained by the Earth system (in which the CO2 related 'lag' effect makes it much warmer than it would otherwise be had it less atmospheric CO2 in it).

Meaning, that whatever heating caused by the above phenomena is already taken into account by Earth system.

Moreover, as jonesdave pointed out, that phenomena/input is 300km altitude, and unless the heating effect continues downwards to more CO2 bearing layers of the atmosphere, it will be constantly re-radiated to space anyway before affecting lower atmosphere/surface heat-driven dynamics.

Having said all that, Chris_Reeve, your speculation re possible contributors to "asymmetric polar heating" is still thought-provoking. Thanks. :)
Whydening Gyre
5 / 5 (2) Apr 24, 2017
The group called this strange purple streak of light in the night sky captured in their photographs a 'proton arc' but for a number of reasons, including the fact that proton aurora are never visible, he knew this had to be something else.
However, nobody knew what it actually was so they decided to put a name to this mystery feature: they called it Steve.

Face, meet palm....

Hey, Dave wasn't home...

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