Mysterious “Aurora Blobs” Explained

May 15, 2023: Europeans are still trying to wrap their minds around what happened after sunset on April 23, 2023. Everyone knew that a CME was coming; photographers were already outside waiting for auroras. But when the auroras appeared, they were very strange.

“I had never seen anything quite like it,” says Heiko Ulbricht of Saxony, Germany. “The auroras began to tear themselves apart, pulsating as they formed individual blobs that floated high in the sky.”

“It literally took my breath away,” he says. “My pulse was still racing hours later!” The same blobs were sighted in France and Poland, and in Denmark they were caught flashing like a disco strobe light.

Ordinary auroras don’t act like this.

Indeed, “these were not ordinary auroras,” confirms space physicist Toshi Nishimura of Boston University. “They are called ‘proton auroras,’ and they come from Earth’s ring current system.”

Most people don’t realize that Earth has rings. Unlike Saturn’s rings, which are vast disks of glittering ice, Earth’s rings are invisible to the naked eye. They are made of electricity–a donut-shaped circuit carrying millions of amps around our planet. The ring current skims the orbits of geosynchronous satellites and plays a huge role in determining the severity of geomagnetic storms.

Sometimes during strong geomagnetic storms, protons rain down from the ring system, causing a secondary shower of electrons, which strike the atmosphere and make auroras. Earth-orbiting satellites have actually seen these protons on their way down. Ordinary auroras, on the other hand, are caused by particles from more distant parts of Earth’s magnetosphere and have nothing to do with Earth’s ring current.

Mystery solved? Not entirely. “We still don’t know why proton auroras seem to tear themselves apart in such a dramatic way,” says Nishimura. “This is a question for future research.”

“It was very exciting to watch,” recalls Ulbricht. “I would definitely like to see these again.”

Good, because they are likely to return. Solar Cycle 25 ramping up to a potentially-strong Solar Maximum next year. Future storms will surely knock more protons loose from the ring current system.

Here’s what to look for: (1) Proton auroras tend to appear around sunset. Why? Electric fields in Earth’s magnetosphere push the protons toward the dusk not dawn side of our planet. (2) Proton auroras love to pulse–a sign of plasma wave activity in Earth’s ring current. (3) Proton auroras are sometimes accompanied by deep red arcs of light (SARs), the glow of heat leaking from the ring current system. These red arcs were also seen on April 23rd.

Solar Max is coming. Let the proton rain begin!

Solar Flares and the Origin of Life

In 1952, the Miller-Urey experiment proved that lightning in the atmosphere of early Earth could produce the chemical building blocks of life. New research reveals that solar flares might do an even better job.

“The production rate of amino acids by solar protons is a thousand times greater than by lightning,” says Vladimir Airapetian of NASA’s Goddard Space Flight Center, a coauthor of the paper published April 28, 2023, in the research journal Life.

Above: An artist’s concept of the early Earth

Early research on the origins of life focused on lightning as an energy source. Stanley Miller of the University of Chicago filled a closed chamber with methane, ammonia, water, and molecular hydrogen – gases thought to be prevalent in Earth’s early atmosphere – and repeatedly ignited an electrical spark to simulate lightning. A week later, Miller and his graduate advisor Harold Urey analyzed the chamber’s contents and found that 20 different amino acids had formed.

“That was a big revelation,” says Airapetian. “From the basic components of early Earth’s atmosphere, you could synthesize these complex organic molecules.”

Unfortunately, the Miller-Urey experiment was wrong about the make-up of Earth’s atmosphere. Scientists now believe ammonia (NH3) and methane (CH4) were far less abundant; instead, Earth’s air was filled with carbon dioxide (CO2) and molecular nitrogen (N2), which require more energy to break down. These gases can still yield amino acids, but in greatly reduced quantities.

Cooking the building blocks of life would require more energy. Seeking alternatives, some scientists pointed to shockwaves from incoming meteors. Others cited solar ultraviolet radiation. In 2016, Airapetian suggested a different idea: energetic particles from our sun.

Chemistry professor Kensei Kobayashi of the Yokohama National University heard about Airapetian’s idea and offered to help test it.

“I was fortunate enough to have access to several [particle accelerators] near our facilities,” says Kobayashi. These accelerators could be used to create energetic protons of the type produced by strong solar flares and CMEs.

Next, they set about re-creating the Miller-Urey experiment with a mixture of gases matching early Earth’s atmosphere as we understand it today. Kobayashi’s team shot the gas-filled chamber with protons (simulating solar particles) or ignited it with spark discharges (simulating lightning), comparing which worked best.

While protons (solar flares) formed amino acids with methane concentrations as low as 0.5%, spark discharges (lightning) required about a 15% methane concentration before any amino acids formed at all. Protons also tended to produce more carboxylic acids (a precursor of amino acids) than spark discharges.

Overall, solar protons outperformed lightning by a factor of a thousand.

This is significant because the young sun produced a lot of energetic protons. Some 4 billion years ago, the sun shone with only about three-quarters the brightness we see today, but its surface roiled with giant eruptions. “Superflares” were common, by some estimates occuring as often as 10 times a day, helping to cook plenty of amino acids.

This doesn’t mean solar flares created life–only the building blocks. How non-living chemicals might self-assemble into a living organism remains a mystery.

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Reversed-Polarity Sunspot Hurls a CME Toward Earth

May 7, 2023: Reversed-polarity sunspot AR3296 just did it again. The backwards active region exploded on May 7th (2234 UT), producing a long-lasting M1.5-class solar flare. The blast was squarely Earth-directed:

Extreme ultraviolet radiation from the flare ionized the top of Earth’s atmosphere, producing a minor shortwave radio blackout over the western USA and the Pacific Ocean: map. Mariners and ham radio operators may have noticed loss of signal at frequencies below 20 MHz for hours after the flare.

This explosion also hurled a CME toward Earth. SOHO coronagraphs recorded a full halo:

A NASA model of the CME predicts that it will arrive during the early hours of May 10th. The impact could cause moderate (G2) to strong (G3) geomagnetic storms. Solar flare alerts: SMS Text.

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Reversed-Polarity Sunspot

May 4, 2023: New sunspot AR3296 is breaking the law: Hale’s Law. The sunspot’s magnetic field is reversed compared to other nearby sunspots in the sun’s northern hemisphere. This magnetogram from NASA’s Solar Dynamics Observatory (SDO) shows the situation:

According to Hale’s Law, Solar Cycle 25 sunspots in the sun’s northern hemisphere should have a -/+ polarity (negative on the left, positive on the right). AR3296 is reversed; its polarity is +/-.

Studies show that about 3% of all sunspots violate Hale’s Law. In most ways, reversed polarity sunspots are totally normal. They have about the same lifespan and size as ordinary sunspots. In one important way, however, they are different. According to a 1982 survey by Frances Tang of the Big Bear Solar Observatory, reversed polarity sunspots are more than twice as likely to develop complex magnetic fields, in which + and – are mixed together. Reversed polarity sunspots are therefore more likely to explode. Solar flare alerts: SMS Text.

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