As the sun begins to roar, Earth’s sky is illuminated with beautiful dancing lights. Colorful polar currents dance and shine in the sky around the poles. But another empirical glow appears near the equator: the red, mauve-pink STEVE and its accompanying green-striped hedge.

What these lights are and why they appear in our sky remains a mystery. Scientists previously thought they might be related because they resemble the aurora borealis, but the mechanisms behind this phenomenon remain elusive. Now a new article offers a radical idea: that STEVE and the fence are clearly not the aurora, but something else.

The team, led by UC Berkeley physicist Claire Gask, says that instead of being created by magnetic fields like the aurora borealis, STEVE and the fence are created by electric fields parallel to magnetic field lines at lower latitudes from the aurora borealis.

If so, this has profound implications for our understanding of Earth’s atmosphere, magnetosphere, their interactions, and physics.

“We’ve known for several years that the STEVE spectrum tells us about very exotic physics. We didn’t know what it was,” says physicist Brian Harding of the University of California, Berkeley. “Claire’s paper showed that parallel electric fields could explain this exotic spectrum.”

The Northern Lights are truly one of the most beautiful places the Earth has to offer. They also have a very interesting physical explanation. They arise when particles from the Sun are flung into space towards Earth, such as those thrown by the strong solar wind or thrown by a giant explosion such as a flare.

When they hit Earth’s protective magnetosphere, most bounce back, but some are captured and thrown into the upper atmosphere, accelerating along magnetic field lines to higher latitudes. There they collide with atmospheric atoms and molecules, briefly exciting them and causing them to glow.

This is the aurora, and its colors range from green to yellow to pink to red to purple, depending on which atoms are ionized. Green is oxygen. Purple or blue is nitrogen. One of the rarest symptoms, the blood-red color, is oxygen, but it is very high in the atmosphere and appears only during the most energetic solar events.

And then there’s the odd mauve and white STEVE, sometimes accompanied by a striped green feature known as a hedge. STEVE, a strong increase in the rate of thermal radiation, was officially identified as a separate phenomenon in 2018, and scientists have been trying to unravel it for years.

“It’s really cool,” says Gasquet. “This is one of the biggest mysteries in space physics right now.”

Scientists believed that STEVE may have been created by a stream of ionized atoms in the upper atmosphere that did not fall as auroral particles, known as a subauroral ion drift, or SAID. Stachetnik was believed to be the result of particles falling from Steve.

But scientists are unsure how SAID, which is not normally associated with STEVE, might produce STEVE-y light. Gask and his team thought there might be another explanation for the fence.

“If you look at the spectrum of the hedge, it is much greener than you expected. “There is also no blue color from nitrogen ionization,” he explains.

“This tells us that the electrons that can create these colors only have a certain energy range, and because these particles have so much energy, they cannot come into the atmosphere from space.”

Instead, Gask and his team have now shown that particles within the enclosure are excited locally by an electric field rather than falling from a high height to a lower one; This is a very different mechanism than the mechanism behind the aurora borealis.