Mysterious aurora-like phenomenon 'STEVE' appears during strongest solar storm for more than half a decade

By Harry Baker

 published 5 days ago

STEVE was spotted across the U.S. and in parts of the U.K. after the most powerful solar storm to hit Earth for six years smashed into our planet.

A vibrant, purple STEVE cuts across the night sky above above Badlands National Park in South Dakota during the late hours of March 23.  (Image credit: Evan Ludes/Framed By Nature)

A bizarre, aurora-like phenomenon known as STEVE made several appearances across the United States and parts of the United Kingdom last week, after a powerful solar storm slammed into Earth without warning. 

STEVE, also known as a "strong thermal emission velocity enhancement," is a rare phenomenon that was officially discovered in 2016. During STEVE, a long, thick ribbon of light — usually white, purple or green in color — appears to hang in the sky for up to an hour. Although it looks very similar to auroras, or northern lights, and often appears at the same time, STEVE is not an aurora.

On March 23, a surprise coronal mass ejection (CME) — a gargantuan, fast-moving blob of plasma and magnetic field released from the sun — erupted from a massive hole in the sun that was wider than 20 Earths. Astronomers did not see the stealthy storm coming because it traveled much slower than normal CMEs and was therefore almost impossible to track. The resulting geomagnetic storm on Earth was the most powerful for six years and triggered spectacular auroras across the globe.  

Related: Blood-red aurora transforms into 'STEVE' before stargazer's eyes

A red and white STEVE accompanied by green "picket fence" auroras in the sky above Washington state.

(Image credit: Rocky Raybell)

STEVE becomes partially obscured by clouds.(Image credit: Rocky Raybell)

STEVE in all its multicolor glory.(Image credit: Rocky Raybell)

The sneaky solar storm also triggered unusually widespread sightings of STEVE. The phenomenon was photographed in South Dakota, Washington state, Idaho, Montana (twice) and in Scotland in the U.K., and it may have been visible in other places as well, according to Spacewaether.com(opens in new tab).

During auroras, highly energetic particles from solar storms and solar wind break through the planet's magnetic field, or magnetosphere, and excite molecules of gas in the upper atmosphere. This creates swirling lights that ebb and flow over time. But STEVE is not triggered by high-energy particles and can occur much further away from Earth's poles than auroras tend to appear — although scientists are still unsure why. 

A second STEVE photographed above Badlands National Park. This emission was accompanied by the iconic green "picket fence" auroras.  (Image credit: Evan Ludes/Framed By Nature)

Instead, STEVE is caused by a river of hot plasma, or ionized gas, that breaks through Earth's magnetosphere and into the ionosphere thanks to magnetic disturbances during solar storms. This plasma travels at around 13,300 mph (21,400 km/h), which creates friction with the surrounding air and excites molecules to glow in the same way as an aurora. But the constant flow of plasma causes an unmoving visual phenomenon for an observer compared with the dancing lights of auroras. 

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STEVE can also be accompanied by streaking green lights, or "picket fences," that flash in the sky for around 30 seconds before disappearing. Experts believe these picket fences form in a similar way to auroras, but the streaking lights are not fully understood.

This is not the first time STEVE has made an appearance above North America. In August 2022, STEVE was spectacularly photographed after it emerged in the skies above southern Canada after another surprise solar storm hit Earth. 

A vibrant, purple STEVE cuts across the night sky above above Badlands National Park in South Dakota during the late hours of March 23. (Image credit: Evan Ludes/Framed By Nature)

Rare blood-red arc of light shines in the Scandinavian sky. What is it?


Harry Baker
Fri, March 31, 2023

A close-up of the red light streaking across the night sky.

A bright red streak of light appeared in the sky above parts of Scandinavia last week after a surprise solar storm smashed into Earth and triggered stunning auroras across the planet. But the bright red band was not an aurora — it was something much rarer.

The streak, which appeared as a river of hazy red light that stretched all the way across the night sky, was most prominently visible above Denmark. Astrophotographer Ruslan Merzlyakov snapped a spectacular shot of the peculiar light show on March 23 above Møns Klint, a set of limestone cliffs on the Danish island of Møn in the Baltic Sea.

The unusual phenomenon is known as a stable auroral red arc (SAR), but despite the name, it is not an aurora or particularly stable, according to Spaceweather.com. Instead, the light is emitted by oxygen molecules in the upper atmosphere that have become superheated by Earth's ring current system, a massive loop of electric current that surrounds our planet.

The SAR coincided with the most powerful geomagnetic storm to hit Earth for six years, which was triggered by a surprise coronal mass ejection — a gargantuan, fast-moving blob of plasma and magnetic field released from the sun — that was spat out of a massive hole in the sun wider than 20 Earths.

The SAR shines above limestone cliffs in Denmark.

During auroras, highly energetic particles from solar storms and solar wind bypass Earth's magnetic field, or magnetosphere, and excite molecules of gas in the upper atmosphere. This creates swirling, multicolor lights that ebb and flow over time. The various colors of light come from different atoms, which emit specific colors when excited.

During SARs, energy from the ring current system, which surrounds the magnetosphere, heats up the gas in the upper atmosphere and makes it glow like an aurora. For unknown reasons, only oxygen is heated up during a SAR, which means these phenomena always emit the exact same shade of red, according to Spaceweather.com.

SARs actually occur quite frequently, but they are normally invisible to humans because they are too faint and our eyes are poorly attuned to the wavelength of red light emitted by SARs, according to Spaceweather.com. Massive streaks like the one over Denmark only become visible when strong solar storms weaken the magnetosphere, which enables more heat from the ring current system to enter the upper atmosphere.

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The SAR over Denmark was not the only unusual light show observed during the recent solar storm. The aurora-like phenomenon STEVE, a large ribbon of colored light that hangs in the sky for up to an hour, was also visible across the United States and parts of the United Kingdom.

There is some evidence that STEVE and SAR arcs are related phenomena. In March 2015, skywatchers in New Zealand watched as a bright red SAR slowly transformed into a STEVE event over the course of about half an hour.

Beetles Hydrate by Drinking Through Their Butt Holes. Here's How They Do It

NATURE29 March 2023

ByREBECCA DYER

A red flour beetle (Tribolium castaneum). (Eric Day/Wikimedia Commons)

All life on Earth depends on water, including us. Some of us consume water the old-fashioned way by drinking it with our mouths, others more creatively.

Beetles can rehydrate themselves by opening their rectums and drinking trace amounts of water floating in the air.

They can also reabsorb water from their poop, and their butts are surprisingly proficient at wringing moisture out of it, too.

With their specialized rectal ability, beetles can survive in the driest regions on Earth, including the flour and grains in your pantry.

We've known about this unique approach to water consumption for more than a century, but now a new study has gotten to the bottom of one of the ways that beetles achieve this.

"A beetle can go through an entire life cycle without drinking liquid water. This is because of their modified rectum and closely applied kidneys, which together make a multi-organ system that is highly specialized in extracting water from the food that they eat and from the air around them," explains biologist Kenneth Veland Halberg from the University of Copenhagen in Denmark.

"In fact, it happens so effectively that the stool samples we have examined were completely dry and without any trace of water."

Microscopic cross-section of the beetle's hindgut. The dry stool is in magenta, surrounded by the intestine in gray. The excretory tube of the beetle is shown in purple. (Kenneth Veland Halberg/University of Copenhagen)

Halberg and his team at the University of Copenhagen worked with researchers from the Universities of Edinburgh and Glasgow in the UK to shed light on how insects have evolved their water-recycling and water-conservation mechanisms.

The red flour beetle (Tribolium castaneum) is often used to study insects because its biology is similar to other insects, its genome is well-sequenced, and it is easily accessible as an everyday kitchen pest.

Red flour beetles (Tribolium castaneum). (Kenneth Veland Halberg/University of Copenhagen)

The researchers used RNA sequencing to compile an atlas, called – you guessed it – BeetleAtlas, detailing the developmental stages of T. castaneum so they could compare gene expression between different organs and at different times in their lives.

By looking in BeetleAtlas for genes that were expressed more in the rectum, the researchers could focus on one in particular, called NHA1.

"The gene we have discovered is essential to this process, which is new knowledge for us," says Halberg.

Halberg and his team found that a protein called Tiptop controls how much NHA1 is made and also helps make leptophragmata cells, a unique group of cells mostly found in the beetle's rectal complex.

Only leptophragmata cells express NHA1, with closer examination showing that these cells play a critical role in the beetle's ability to take in water via its posterior.

"As the beetle's kidneys encircle its hindgut, the leptophragmata cells function by pumping salts into the kidneys so that they are able to harvest water from moist air through their rectums and from here into their bodies," Halberg explains.

Diagram of the beetles inside showing how it obtains water from the air. (Kenneth Veland Halberg/University of Copenhagen)

The team showed that NHA1 expression increased in beetle butts when the animals were exposed to drier conditions, allowing them to absorb more water from the environment and their feces.

What's more, when NHA1 functionality was turned off in the lab, the beetles lost more water through excretion, making it harder for them to survive in dry conditions and demonstrating that NHA1 is important for the transport of water from their rectums to their body.

While these findings help us understand the beetles better, they can also serve a practical purpose.

Thousands of tons of food are lost every year due to insect pests, and the impact on developing countries' food security is particularly severe. So finding ways to mitigate beetle pests is vital, but many beetles and other insects are critically important to our world, so we need to protect them.

"Insects are particularly sensitive to changes in their water balance," says Halberg. "As such, this knowledge can be used to develop more targeted methods to combat beetle species which destroy our food production, without killing other animals or harming humans and nature."

To facilitate future studies, the authors have made BeetleAtlas available to other scientists. Expression in over 16,500 genes in the Tribolium genome can now be easily compared thanks to their RNA sequencing that spans embryonic, larval, and adult stages.

The research has been published in Proceedings of the National Academy of Sciences.