Does it ever seem like all the impressive solar flares always miss our planet?

As Aurora Chasers, we are eager to see solar activity that makes an enormous impact, producing strong space weather and creating action here on Earth. But many things have to happen for a solar flare to have any visible impact on our night skies.

In an analysis conducted by SolarHam, nearly 70 percent of the largest solar flares — or X-Flares — occurred in locations on the sun’s surface that were far from ideal. These happened on the east limb of the sun, before the sunspot region turns to face Earth, or on the sun’s west limb, as the solar activity proceeds to rotate out of view.

Out of 23 X-Class solar flares detected during the first five years of Solar Cycle 25, only two solar flares occurred in positions that were almost directly facing Earth, according to SolarHam. One failed to launch a Coronal Mass Ejection (CME) into space, and the other created a CME that mostly missed the Earth, leaving many Aurora Chasers disappointed.

Just based on the oversimplified idea that only half of the sun faces the Earth, we can expect at least half of the Coronal Mass Ejections from solar flares to miss our planet. Realistically, way more than that will be a miss.

Occasionally, though, we will see a powerful solar flare that ejects solar plasma from the sun’s surface, bringing us the potential for Northern Lights or Southern Lights. So, how can you know the difference between a non-starter and the geomagnetic storm of a lifetime?

Solar Flares Don’t Always Create Impacts on Earth

The sun and the dynamic activity on the sun’s surface pose many risks to our planet, its infrastructure, and the way humans and technology survive and operate in outer space. Impacts from the strongest types of this activity include damage to transformers, communication system disruptions, satellite shake, blackouts or voltage control problems in power systems, and malfunctions in satellite-based GPS systems.

That’s why scientists and organizations have invested countless resources in trying to analyze solar flares and other types of solar activity, as well as the space weather that these events can produce. 

A solar flare is an intense burst of electromagnetic radiation that comes from the release of the sun’s magnetic energy. Solar flares can last from minutes to hours, and they are measured on a scale that classifies each flare by intensity, from B-Flares which barely register to X-Flares which pack a massive punch.

At a glance, a solar flare just sounds exciting! However, only some solar flares create powerful space weather that can penetrate Earth’s magnetic field and lead to brilliant displays of Aurora. That’s a common misconception among novice Aurora Chasers.

While it’s true that solar flares can eject matter off the sun’s surface, sending solar wind into outer space, this doesn’t always happen. The sun is so powerful that a vast number of solar flares fire up, create a beautiful loop on solar images, and then get sucked right back into the sun’s corona, from where they came. We need to see dense, fast, and favorably charged solar wind release from a solar flare, if we expect to see any Northern Lights in the days after one of these bursts.

Solar flares are actually fairly common, and they have to become part of a greater process to matter to an Aurora Chaser. For our purposes, let’s simplify the process. Knowing the basic steps for tracking a solar flare could help you understand when to get excited for potential activity on Earth — and when to sit back and enjoy the solar images.

Five Simple Steps for Tracking Solar Flares

The best analysis of the movement and impact from a solar flare comes from carefully studying space weather models, solar imagery, locations and trajectories. But finding helpful information about a solar flare doesn’t have to be difficult. Fortunately, most of the crucial details are now easily available to Aurora Chasers, distributed through a broad range of websites, social media accounts or apps.

If you’re wondering whether we’ll see a chance of Aurora created by a solar flare, you can use these simple steps to determine if a solar flare might lead to activity that impacts the Earth.

First, a Radio Blackout is detected. This is one of the earliest potential indicators of activity you’ll see in alerts from the Space Weather Live app. By itself, it means very little to us as chasers, but it’s an early sign to watch for.

Second, the Solar Flare shows up in modeling and we can image its location and potential direction. Solar Flares of C-Class or lower don’t pack as much power. It’s strong C-Flares, M-Flares and X- Flares that we prefer to watch for the purposes of Aurora Chasing in our region. (Also of note, flares are not the only cause of Aurora.)

Third, a Solar Flare must launch a CME (Coronal Mass Ejection) into outer space for it to potentially become geoeffective — meaning it will have effects on Earth. If there’s no CME, the plasma in that Solar Flare just returns to the sun’s corona from where it came.

Fourth, the CME must be directed toward, not away from, the Earth. Side-swipes, glancing blows, transient impacts on the solar wind, these all have potential to create instability in the magnetic field and produce Aurora. However, the high confidence events come when there is an Earth-directed CME.

Fifth, the orientation of the Interplanetary Magnetic Field — the Bz from the solar wind (and CME) itself — must be tipped in our favor. A negative Bz (or a Bz that rapidly oscillates from positive to negative) allows more powerful Aurora to swirl in Earth’s atmosphere, pushing strong Northern Lights to lower latitudes, like Michigan and the Great Lakes region.

Radio Blackout > Solar Flare > CME > Earth-directed > Favorable Bz
Then, we hope all the conditions on Earth align!

Are you wondering where to get started to track the next solar flare? Download the Space Weather Live app, follow SolarHam online, or visit national forecasting agency websites such as the Space Weather Prediction Center, to name a few. There are many platforms where you can find this information.

The Next Step: Taking Other Space Weather into Consideration

Now, here’s the catch! We could track a solar flare that passes each step, and it could still amount to nothing. How is that possible? It all comes back to the many conditions that need to align to create Aurora, and the dozens of variables and unknowns Aurora Chasers face. Consider what could happen from the moment a solar flare erupts on the sun to the second the solar wind reaches Earth’s magnetic field.

What if more than one solar flare is detected? What if we see multiple CMEs? What if the CME changes direction along the way? What if a solar flare coincides with a filament eruption and a high-speed stream from a coronal hole? What if the solar wind created by this activity loses power or speed in its journey between the sun and the Earth?

Any number of scenarios could play out, while we to see the outcome. These might include one CME deflecting another, one CME colliding with another to change the timing of a potential impact, or the solar wind missing our planet entirely.

For the beginners in the room, you can see that space weather — the source of the geomagnetic disturbances that create Aurora — is a complex topic. It’s a fascinating field of scientific study with lots of resources for even amateur space weather enthusiasts to learn more. Further study is exactly what it will take if you truly want to understand how different space weather events can interact and counteract.

As you start tracking solar flares, just remember that there are many other forces and objects in space that can influence the trajectory of a CME, even when it appears to be Earth-directed.

SolarHam, Space Weather Live, the Space Weather Prediction Center, and variations in space weather modeling like the WSA-ENLIL Model make great resources to follow for early analysis. If you learn the ropes, these websites, models, and apps can alert you to potential Aurora before many other Aurora Chasers even know there’s a chance.

If you want to know when we have high confidence from a solar flare or space weather event, though, you’ll need to consider all of these steps (and more) in the process it takes to create visible Northern Lights.

In the photo, the “aurora australis” hovers above the Earth’s horizon as the International Space Station nears the southern-most point of its orbital trek above the Indian Ocean in April 2020. Courtesy of NASA.