An article published in the journal Nature Communications this week suggests that the natural light show starts when disturbances on the sun pull on Earth’s magnetic field. That creates cosmic undulations known as Alfvén waves that launch electrons at high speeds into Earth’s atmosphere where they create the aurora.
“It was sort of theorized that that’s where the energy exchange is occurring,” said Gregory Howes, associate professor of physics and astronomy at the University of Iowa. “But no one had ever come up with a definitive demonstration that the Alfvén waves actually accelerate these electrons under the appropriate conditions that you have in space above the aurora.”
The sun is volatile, and violent events there such as geomagnetic storms can echo out into the universe. In some cases, the sun’s disturbances are so strong that they yank on the Earth’s magnetic field like a rubber band, pulling it away from our planet.
But, like a taut rubber band when it’s released, the magnetic field snaps back, and the force of that recoil creates powerful ripples known as Alfvén waves about 80,000 miles from the ground. As those waves get closer to Earth, they move even faster thanks to the planet’s magnetic pull.
…”Think about surfing,” said Jim Schroeder, an assistant physics professor at Wheaton College and the article’s lead author. “In order to surf, you need to paddle up to the right speed for an ocean wave to pick you up and accelerate you, and we found that electrons were surfing. If they were moving with the right speed relative to the wave, they would get picked up and accelerated.”
When the electrons reach Earth’s thin upper atmosphere, they collide with nitrogen and oxygen molecules, sending them into an excited state. The excited electrons eventually calm down and release light, which is what we see as the aurora.
A typical aurora — sometimes called the northern lights or the southern lights, depending on the hemisphere in which it’s located — occurs when charged particles from the sun interact with Earth’s oxygen and nitrogen molecules. This interaction excites the molecules and causes them to glow.
But STEVE, formally known as Strong Thermal Emission Velocity Enhancement, is different. In the Northern Hemisphere, the phenomenon is visible from areas farther south than a typical aurora, and it looks like a ribbon of pink or mauve light. Sometimes, STEVE even has a “picket fence” appearance, with green columns of light passing through the ribbon. Auroras, by contrast, usually are shimmering green ribbons.
…The new study examined satellite data gathered above STEVE events in April 2008 and May 2016. The measurements included information about Earth’s magnetic and electrical fields in the magnetosphere, the region of Earth’s atmosphere where the planet’s magnetic field is stronger than any influence coming from the sun. Then, scientists compared the satellites’ findings with amateur photos of STEVE taken from the ground at the same time.
When STEVE was on display, the study authors realized, energetic electrons were pouring into Earth’s ionosphere, the layer of the planet’s atmosphere where atoms lose electrons due to solar and cosmic radiation. The friction that flood creates heats particles, which creates the pinkish glow, almost like an incandescent light bulb.
Satellite information further revealed how the “picket fence” aspect of STEVE develops. The data revealed waves moving from Earth’s magnetosphere to the ionosphere. In this region, the waves can both energize electrons and move them out of the magnetosphere, creating the picket-fence appearance, which happens simultaneously in the Northern and Southern hemispheres.
The NOAA/NWS Space Weather Prediction Center reports that geomagnetic Storm Watches are in effect from December 10th & 11th, 2020 due to anticipated Coronal Mass Ejection (CME) effects giving us a good chance of seeing the northern lights! The CME occurred on December 7th and analysis suggests CME arrival possible late on 9 December, initially resulting in G1 (Minor) storm levels. As CME effects continue, activity is likely to increase, especially if the magnetic field carried with the CME connects well with Earth’s magnetosphere. The potential for strong storm levels exists and a G3 (Strong) Watch is in effect for December 10th. CME-related disturbances are forecast to continue into 11 December, likely resulting in G2 (Moderate) storm levels
As a quick rule of thumb, we can occasionally see Northern Lights at the G1 level, often at G2 and almost definitely at G3. Here’s hoping for clear skies!!
Aaron took this photo at Otter Creek in the Sleeping Bear Dunes National Lakeshore back in March of 2015 & shared: A very memorable night. After seeing all 4 indicators in red on [a now defunct aurora tracker website] (and I had never seen that before), I bolted for the lake with what was an already late start. Soon after arriving I punched through the ice while jumping from flow to flow in the shallows. This was the first time I have ever shot these and despite having one leg wet to the knee I managed to stay out for five hours on sheer excitement.
Space.com says that those who have gotten up before sunrise to gaze into the twilight skies to see Comet Neowise have been greeted by the best comet performance for Northern Hemisphere observers since the 1997 appearance of Comet Hale-Bopp, emphatically ending nearly a quarter-century of lack of spectacular comets, and it’s only going to get better:
The first good opportunity for evening viewing begins on July 12, when the head of the comet will stand 5 degrees above the north-northwest horizon, 80 minutes after sunset (the end of nautical twilight). By July 14 its altitude will have already doubled to 10 degrees, and by July 19 it will have doubled yet again to 20 degrees up by the end of nautical twilight. By then it will have moved to above the northwest horizon.
So, we at Space.com feel that the best time to view the comet during the evening will come during the July 14-19 time frame.
We also strongly recommend that observers should seek the most favorable conditions possible. Even a bright comet, like this one, can be obliterated by thin horizon clouds, haze, humid air, smoke, twilight glow and especially city lights. We especially emphasize that last factor: the farther away you get from a metropolitan area, the darker your sky and the better your view of NEOWISE. Binoculars will enhance your view.
And more good news: No moonlight will brighten the sky, as the moon will be a waning crescent and visible only in the morning sky through July 20. On successive July evenings the comet will grow fainter, but it will be farther from the sun, setting later and visible in a darker sky. As we move into August, the comet will be very well placed for observers with small telescopes.
Read on for more tips & happy comet hunting to you all!
Ken was in the Sleeping Bear Dunes National Lakeshore looking towards the Manitou Islands & writes that he captured Comet Neowise, the Northern Lights and an Iridium Flare plus the bonus reflection on Lake Michigan!! The bright light to right of center horizon is the South Manitou Island Lighthouse. See it bigger on Facebook.
A Conflagration of Storms from his online book The 23rd Cycle, Dr. Sten Odenwald tells of the evening of March 13, 1989 when a massive wave of solar energy struck our atmosphere, creating one of the most impressive northern lights displays of the modern era.
Alaskan and Scandinavian observers were treated to a spectacular auroral display that night. Intense colors from the rare Great Aurora painted the skies around the world in vivid shapes that moved like legendary dragons. Ghostly celestial armies battled from sunset to midnight. Newspapers that reported this event considered the aurora, itself, to be the most newsworthy aspect of the storm. Seen as far south as Florida and Cuba, the vast majority of people in the Northern Hemisphere had never seen such a spectacle. Some even worried that a nuclear first-strike might be in progress.
Luke Pontin, a charter boat operator in the Florida Keys, described the colors in reddish hues as they reflected from the warm Caribbean waters. In Salt Lake City, Raymond Niesporek nearly lost his fish while starring transfixed at the northern display. He had no idea what it was until he returned home and heard about the rare aurora over Utah from the evening news. Although most of the Midwest was clouded over, in Austin Texas, Meteorologist Rich Knight at KXAN had to deal with hundreds of callers asking about what they were seeing. The first thing on many people’s mind was the Space Shuttle Discovery (STS29) which had been launched on March 13 at 9:57 AM. Had it exploded? Was it coming apart and raining down over the Earth? Millions marveled at the beautiful celestial spectacle, and solar physicists delighted in the new data it brought to them, but many more were not so happy about it.
Silently, the storm had impacted the magnetic field of the Earth and caused a powerful jet stream of current to flow 1000 miles above the ground. Like a drunken serpent, its coils gyrated and swooped downwards in latitude, deep into North America. As midnight came and went, invisible electromagnetic forces were staging their own pitched battle in a vast arena bounded by the sky above and the rocky subterranean reaches of the Earth. A river of charged particles and electrons in the ionosphere flowed from west to east, inducing powerful electrical currents in the ground that surged into many natural nooks and crannies. There, beneath the surface, natural rock resistance murdered them quietly in the night. Nature has its own effective defenses for these currents, but human technology was not so fortunate on this particular night. The currents eventually found harbor in the electrical systems of Great Britain, the United States and Canada.
The K-index is a scale that measures geomagnetic activity and the NOAA NWS Space Weather Prediction Center says we’re looking at a potential K-index of SIX tonight! That means Northern Lights are very likely tonight! Click the link above for much more and to subscribe to aurora alerts!
“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.” ― Marie Curie
The NOAA/NWS Space Weather Prediction Center (SWPC) has forecast a G2 level storm for tonight, which may very well produce Northern Lights! The SWPC is an invaluable scientific resource that is wholly produced by our tax dollars. In addition to letting us know when northern lights are possible, the SWPC helps to maintain our modern communication grid when the Sun gets a little extra exuberant.
It’s my heartfelt belief that one of the duties of our government is to work to make our country the leader in scientific advancement. As threats in public health, the environment, and a host of other realms increase, we need to be investing much more in science, not less.