NOAA’s Space Weather Prediction Center has extended the G3 (Strong) geomagnetic storm warning through 09:00 UTC on June 3. More aurora activity is likely.
Huge Solar Flare Erupts
The flare was detected on May 30, and it lasted around two hours, peaking at 00:05 UTC, May 31. It’s classified as an M-class flare—the second strongest category of solar flares.
The M8 solar flare was followed by a full halo coronal mass ejection (CME)—a massive burst of plasma containing solar particles and magnetic fields launched from the Sun—part of which was directed towards Earth, and impacted our planet on June 1.
Earth-Directed CME
Because the CME was Earth-directed, it interacted with Earth’s magnetic field, triggering a geomagnetic storm. This type of space weather event often causes vibrant auroras that can be seen much farther from the usual auroral zones.
According to NOAA’s Space Weather Prediction Center, a strong (G3) to severe (G4) geomagnetic storm watch was in place for June 1. A G3 alert remains in place until 21:00 UTC on June 2.
For fans of the aurora borealis, also known as the northern lights, now may be a great time to look up at the night sky. Meanwhile, skywatchers in the Southern Hemisphere might get a rare glimpse of the aurora australis, or southern lights.
We can usually see the effects of a CME on Earth within a couple of days. The effects of a solar flare, however, only take around 8 minutes to reach us as the electromagnetic radiation from a solar flare travels at the speed of light.
“The CME that followed the M8 flare struck earlier than expected,” says Dr. Renate Mauland-Hus, our in-house astrophysicist. “High solar wind speeds of over 1000 km/s were also recorded, which is a significant increase from the usual solar wind at around 400 km/s.”
Where Might Auroras Be Visible?
Auroras could be visible as far south as the northern United States, in places like Washington, Montana, North Dakota, Minnesota, Wisconsin, Michigan, and possibly even New York. Elsewhere in the Northern Hemisphere, parts of central and northern Europe may find auroras gracing their skies.
Over in the Southern Hemisphere, you might get the rare chance to spot the aurora as far north as Southern Australia or New Zealand.
Your best chance to see them? Over the next few days, head outside when the sky is dark after the end of civil twilight, find a spot away from city lights, and look north if you’re in the Northern Hemisphere or south if you’re in the Southern Hemisphere.
Find out when civil twilight occurs in your locationIf you are located very far north during a strong geomagnetic storm, the northern lights are more likely to appear directly above you rather than close to the horizon. Auroras usually appear as glowing green or red bands or arcs across the sky, sometimes dancing and shifting shape.
Why Auroras Happen
When particles from the Sun reach Earth, they interact with gases in our atmosphere, like oxygen and nitrogen. This creates glowing curtains of light called auroras, usually green, but sometimes red, purple, or even blue, depending on the gases and the energy involved.
We’re currently in a period known as solar maximum, the most active phase in the Sun’s 11-year solar cycle, marked by increased sunspots and frequent solar eruptions. That means that, during solar maximum, solar flares and CMEs are more likely, making beautiful auroras more likely too.
What Are the Different Types of Flares?
But not all solar flares are created equal—scientists group them into different categories based on their strength:
- A-class and B-class flares are very small. They don’t have much impact on Earth.
- C-class flares are a little stronger. They usually cause minor effects, if any.
- M-class flares are medium-sized. These can sometimes cause radio blackouts near Earth’s poles and create brighter auroras if linked to a CME.
- X-class flares are the biggest and most powerful and can lead to widespread radio blackouts. If accompanied by a CME, they can also produce strong geomagnetic storms and spectacular auroras even far from the poles.
NASA explains that solar flare classes work “much like the Richter scale for earthquakes,” where each higher class is 10 times more energetic than the one before. So, an X-class flare is 10 times stronger than an M-class flare and 100 times stronger than a C-class flare.
Each class also has a scale, from 1 to 9—the higher the number, the stronger the flare, though X-class flares have no upper limit.
The Effects of Solar Flares
Luckily for us, Earth’s magnetosphere—an invisible magnetic shield—protects us from much of the harmful particle radiation emitted by solar activity, and our planet’s atmosphere shields us from electromagnetic radiation. However, there are still several ways in which a solar flare can affect our daily lives:
Communication disruptions: Solar flares can cause radio blackouts, especially on the sunlit side of Earth, by interfering with high-frequency radio waves in the ionosphere—our planet’s ionized upper atmosphere.
Power grid vulnerability: When strong solar flares are accompanied by CMEs directed at Earth, they can trigger geomagnetic storms. These storms may induce electrical currents in power lines, potentially damaging transformers and causing widespread blackouts.
GPS and navigation impact: Solar activity can interfere with satellite signals, leading to GPS errors and reduced accuracy in navigation systems.
Astronaut safety: Astronauts in low Earth orbit (LEO)—such as those on the International Space Station—are mostly protected by the magnetosphere, though they still experience increased radiation during major solar events.
In contrast, astronauts on missions to the Moon or Mars would be fully exposed to solar flare radiation, making radiation shielding critical for deep space travel.
Satellite vulnerability in LEO: Satellites in LEO are not immune to solar flare effects. Despite partial protection from the magnetosphere, solar radiation can:
- cause electronic malfunctions;
- lead to surface charging and potential short circuits;
- increase atmospheric drag, altering orbits and requiring course corrections;
- disrupt communications and onboard systems.
The latest solar flare was a powerful M8 flare associated with an Earth-directed CME, which means skywatchers around the world have witnessed—and may still witness—incredible displays of the aurora.
So keep your eyes on the night sky in the coming days—you might just witness one of nature’s most breathtaking light shows.