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Massive Aurora Displays Posed for a Repeat on June 6

pink auroras
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Josh Davis
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What Goes Into an Aurora Forecast

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Excitement accompanied the numerous auroras seen a few weeks ago. The good news is that the incredibly powerful sunspot group that created the Northern Lights will appear again for a few nights on either side of Thursday, June 6. This is also the night of the new Moon, so we may see more wondrous displays. Get the facts from astronomer Bob Berman.

The Record-Setting May 2024 Auroras

On May 10, the colorful, shimmering displays of light called auroras appeared in many places they’d never been seen before. Here at the Almanac, we were bowled over by the hundreds of reader photos on our Almanac Facebook page, and they were truly stunning, even with a basic phone camera.  

In the U.S., this magical light show appeared as far south as Florida. This is highly unusual as Northern Lights are usually more prevalent in the far north, near the poles.

Further, instead of the more common green colors, many viewers saw unusual pink and reddish colors! This was related to the very high altitude of the far-spreading Northern Lights.

The June 6 Aurora Forecast

The aurora display across the globe on May 10 was primarily due to a super-big sunspot, which had the catchy name AR13664 but has now been renamed AR13697

This sunspot—essentially a massive storm on the Sun—was close to the center of the Sun when it was facing Earth and flinging out large expulsions of plasma and magnetic field from the Sun’s corona. 

Since May 10, the sunspot rotated out of sight (the Sun rotates every 27 days), but it’s about to emerge again on Thursday, June 6.

 For two to three nights on either side of June 6, we may again see a Northern Lights show at low latitudes across North America (and Europe). Even better, June 6 is the month’s new Moon, so the light show will be easier to see. 

How do we know if early June will bring another stunning aurora display across the world? There are several factors at play. Let’s get into the violent details of “space weather” to see what all of this really means.

Factor 1: The Sun’s Cycle

Essentially, a whole lot of physical violence created these record-setting displays a few weeks ago. The Sun is wildly stormy, and we feel its effects on Earth. Scientists use the term “Space Weather” to describe the dramatic emissions from the Sun. 

Why is the Sun so stormy right now? The Sun’s activity level famously gets stronger and weaker in a roughly 11-year solar cycle. Experts believe we’re heading towards the peak of the current cycle, number 25. See the predictions of when Solar Cycle 25 will end. A very active sun cycle results in more visible auroras.

Factor 2: A Sunspot With Massive CMEs

Sunspots like AR13697 appear as dark spots on the Sun’s surface but form when intense magnetic fields deep within the Sun well up to the surface. 

Without going into more scientific explanation, know that the magnetic fields sometimes get all twisted and this produces extreme violence, such as flares, which spew energy and plasma (broken bits of atoms) into their surroundings.

Violent flares erupt from the Sun; these are labeled M-class. Super-violent ones are labeled X-class. A month ago, we had a whole series of X-class flares. 

But those can still be small potatoes compared to the even more violent events called CMEs, or Coronal Mass Ejections, where 10 billion tons of sun-stuff can be blasted off like an enormous shotgun discharge, aimed in one direction. 

Factor 3: Direction of the Solar Flares and CMEs

So you need a sunspot that’s ejecting masses of magnetic material or CMEs. But how do we know that they will travel in space towards Earth? 

CMEs are directional, and the mass of material has its own magnetic field! That field has a spiral pattern, named for the brilliant Eugene Parker, who uncovered it after first discovering and naming “solar wind.”

Solar wind is a more-or-less steady stream of Sun debris that typically sweeps past Earth at around 300 miles a second. Each cubic centimeter or sugar-cube piece of space typically contains five solar wind particles. But flares, and especially CMEs, enormously multiply the density of material hitting us, as well as the speed of impact.

And wait, this is where the story’s greatest drama is just beginning. The solar material hits Earth’s magnetosphere, our Earth’s magnetic field.

Factor 4: Aligned Magnetic Fields 

Or maybe it doesn’t. If the field’s north and south poles happen to be aligned to match Earth’s, the solar material will not interact with us at all. It’ll just keep going outward, perhaps to harass other planets and maybe create the huge auroras we see on Jupiter and Saturn.

But if the CME’s material’s magnetism is oriented opposite to Earth’s field, then it comes right on in to interact with us and possibly create damage to electronics and satellites, threaten electrical transmission facilities and pipelines, and concoct gorgeous auroras. 

How? Glad you asked. Atom fragments like electrons and protons each have an electrical charge. And when a charged particle sweeps past a magnetic field, awesome electricity is generated. In this case, we’re talking about millions of amps—power that makes lightning seem like a bit of static electricity from a winter doorknob.

This electricity excites the atoms of our air. Oxygen is most dramatically affected. As its eight newly-excited electrons settle back down to their preferred orbitals, bits of colored light are produced. (The only way light is ever created in the entire universe is when an electron moves inward, closer to its atom’s nucleus.) 

Oxygen’s most common color emission is green (at 557.7 nanometers wavelength if you love physics and want to know such things.) That’s good luck for humans since that happens to be the tint where our retinas are most sensitive to faint light. So green auroras are the tuna-on-white of this whole aurora business. But high-altitude oxygen tends to create red (at 640 nanometers if you insist on knowing. That’s the same shade of red as most laser pointers.)

The rare pink-red colors indicate very high altitude auroras mostly caused by sparse glowing oxygen.

And that’s the aurora story. We first need a huge local solar magnetic field, yielding spots, and then flares or CMEs. These storms never sit on the Sun’s equator, not very near its poles. 

Bottom-Line on June 6 Auroras

  1. The super-big spot (AR13697) will need to rotate back to the place just to the right of the Sun’s center.  
  2. Then, the sunspot must hurl explosive detritus into space.
  3. Then, the Parker Spiral guides to Earth (after 2 ½ days of travel).
  4. Then, one final thing: We have to hope its own magnetic field is aligned opposite to Earth’s, with the south pointing up. This is a little complicated, but the point it …

We won’t know this until it’s almost here. That’s why aurora predictions sometimes fail.

But when all these things come together, wow. Just wow. We can probably now be confident that solar cycle 25 has NOT been a dud, and we can stop worrying about another Maunder Minimum. Instead, dust off our cameras and head to a dark place!

Note: To get the very latest alert on whether the aurora is happening that night or not, check the latest news from space weather experts.
         

About The Author

Bob Berman

Bob Berman, astronomer editor for The Old Farmer’s Almanac, covers everything under the Sun (and Moon)! Bob is the world’s most widely read astronomer and has written ten popular books. Read More from Bob Berman

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