"Steve" phenomenon resembles an aurora and has a newly-discovered twin

A new celestial phenomenon was discovered recently thanks to the keen eye of a photographer and the invaluable data from ESA’s Swarm satellites. This finding suggests that Steve, a mysterious purple ribbon of light in the night sky, may have a secret twin.

Sota Nanjo, along with a team of international scientists, and Tromsø-based photographer Gabriel Arne Hofstra, uncovered this fascinating development.

The team created an application that collects images of the aurora’s nightly dances above the Norwegian Arctic from the all-sky digital camera at the Ramfjordmoen Research Station.

Their collaborative efforts have shed new light on the enigmatic Steve and its potential sibling.

Enigmatic “Steve” is a mauve marvel

Steve, short for Strong Thermal Emission Velocity Enhancement, is a fast-moving stream of extremely hot gases that travels westward at dusk, creating a stunning display of mauve light in the sky.

The Alberta Aurora Chasers Facebook group, known for their keen observations and stunning photography, brought this mysterious phenomenon to the forefront of scientific curiosity.

Unique spectacle in the night sky

What sets Steve apart from the traditional aurora borealis is its distinctive mauve hue and fleeting nature.

Unlike the northern lights, which typically display shades of green, blue, and red and can persist for hours, Steve’s appearance is brief and characterized by its striking purple color.

Fast-moving stream of hot gases

As scientists sought to understand the nature of Steve, ESA’s trio of magnetic-field monitoring Swarm satellites played a crucial role.

These satellites, strategically positioned in Earth’s orbit, provided valuable data that helped researchers uncover the true identity of this elusive phenomenon.

Through the analysis of Swarm satellite data, scientists discovered that Steve is actually a sub-auroral ion drift, or a strong thermal emission velocity enhancement.

Searching for Steve’s dawn-side twin

While Steve’s appearance at dusk has been well-documented, researchers have been intrigued by the possibility of a similar phenomenon occurring at dawn.

Since there is an equivalent eastward stream of hot gases after midnight, scientists have hypothesized the existence of a dawn-side twin for Steve.

While sifting through the data archives, Gabriel Arne Hofstra stumbled upon something peculiar in an image from December 28, 2021. It was a Steve-like phenomenon, but with distinct differences.

“It has been amazing to have contributed to new science and help scientists uncover this phenomena. To me it proves that we citizens can contribute to understanding the world we live in by collaborating with scientists,” Hofstra said, expressing his excitement.

Swarm data: Steve’s twin vs. aurora borealis

The newly discovered arc, measuring 1000 km in length, appeared after midnight on the dawn side and was poleward of the visible green aurora.

Although none of ESA’s Swarm satellites flew directly through the arc at the precise time and place observed in the all-sky image, two of the satellites’ electric field instruments were able to measure the conditions in the purple region before, during, and after the event.

The data revealed the hallmarks of an eastward ion flow in the purple region.

Scientists and photographers join forces

“As a scientist, collaborating with a photographer to uncover this new phenomenon has been a fantastic experience,” Sota Nanjo of the University of Electro-Communications enthused, highlighting the significance of interdisciplinary collaboration in scientific discoveries.

Nanjo further emphasized that such partnerships advance our understanding of auroral physics while proving the power of continuous cooperation between researchers from diverse fields.

Steve, Swarm, and citizen science

The discovery of Steve’s potential twin highlights the significance of citizen science. With the prevalence of digital cameras, almost everyone has the opportunity to contribute to scientific discoveries.

Anja Strømme, Swarm Mission Manager, expressed her enthusiasm for the role of citizen science in scientific discoveries. “It’s great to see yet another example of successful citizen science,” Strømme remarked.

She emphasized that the synergy between the vast collection of images captured by individuals across the globe and the invaluable data provided by ESA’s heliophysics observatory satellites, such as Swarm, will significantly enhance our comprehension of the impact of space weather on Earth’s atmosphere.

Anticipating extraordinary solar phenomena

As we enter a period of heightened solar activity, we can expect to witness extraordinary celestial phenomena.

“If we have more ‘eyes on the sky’, we can help unravel its mysteries. I really hope that the recent great geomagnetic storm and spectacular skies has encouraged more people to be interested in space physics and contribute to our scientific understanding of our world,” Hofstra expressed optimistically.

He emphasized that with increased public participation and more individuals keeping a watchful eye on the night sky, we can collectively work towards unraveling the mysteries of the universe and advancing our knowledge of the cosmos.

Understanding Aurora Borealis mechanics

The sun constantly emits a stream of charged particles called the solar wind. When these particles encounter the Earth’s magnetic field, they accelerate towards the poles.

As the excited or ionized particles return to their normal state, they emit energy in the form of light. The color of the light depends on the type of particle and the altitude at which the collision occurs.

• Oxygen atoms at lower altitudes (around 60 miles) produce the most common yellowish-green color.
• Oxygen atoms at higher altitudes (around 200 miles) create rare, all-red auroras.
• Nitrogen atoms contribute to the blue and purple hues.

The Aurora Borealis is most frequently seen in a ring-like zone around the Earth’s magnetic poles called the aurora oval.

This oval expands and contracts depending on the intensity of the solar wind. During strong solar storms, the oval can extend to lower latitudes, making the Northern Lights visible in regions far from the poles.

Magnetic reconnection occurs when the Earth’s magnetic field lines and the solar wind’s magnetic field lines connect and rearrange.

This process releases a significant amount of energy, which accelerates the charged particles towards the Earth’s atmosphere, intensifying the auroral display. These intense periods of activity are known as substorms.

The Aurora Borealis is most visible in regions near the Earth’s magnetic poles, such as Iceland, Norway, Sweden, Finland, and Alaska. During geomagnetic storms, the northern lights can we seen as far south as Texas in the U.S.

Swarm provides invaluable Steve data

In summary, the discovery of Steve’s potential twin is a testament to the power of collaboration between scientists and citizen scientists.

As we continue to explore the mysteries of the cosmos, the importance of continuous collaboration and the role of digital cameras in capturing these celestial wonders cannot be overstated.

With more eyes on the sky and the invaluable data from satellites like ESA’s Swarm, we can look forward to unraveling the secrets of our universe and gaining a deeper understanding of the awe-inspiring phenomena that light up our night skies.

The full study was published in the journal Earth, Planets and Space.

Researchers from the Swedish Institute of Space Physics and the Arctic University of Norway also contributed to this fascinating research.

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