The Sun is more than just a bright light in the sky—it’s a cosmic powerhouse that can mess with our planet in many ways. Every 11 years, it goes through a cycle of getting super active (with dark spots called sunspots and solar storms). But there’s a bigger pattern, called the 100-year solar cycle or Gleissberg cycle, that decides whether these 11-year cycles are wild or tame over a century. In 2025, we’re starting a new phase where the Sun might get extra feisty, and this could shake things up on Earth.
What Is the 100-Year Solar Cycle?
Think of the Sun like a massive gas lighter. Every 11 years, it cranks up the power with sunspots and solar storms (like big bursts of energy) and then dials it back down. The 100-year cycle is like a cycle, making those 11-year bursts over about 80–100 years. When the cycle’s in a “high” mode, the Sun throws out more solar flares (bright flashes) and coronal mass ejections (CMEs, like giant clouds of charged particles). In a “low” mode, it’s calmer, with fewer storms.
These patterns have been seen for centuries by counting sunspots (since the 1600s) and checking clues like particles trapped in ancient ice. We've noticed the Sun switches between active times (like the 1950s, with lots of storms) and quiet ones (like the early 1800s, when it was sleepy). This is driven by the Sun’s magnetic field, which acts like a big magnet flipping and changing over time.
Why Is It Happening Now?
In 2025, the Sun’s in the middle of its 11-year cycle (called Solar Cycle 25, peaking around now), and it’s already acting up with big flares. But what’s concerning is that we’re starting a new 100-year cycle where the Sun gets more active. Scientists found this by looking at particles in a radiation zone around Earth (called the Van Allen belts) in 2024, which showed signs of the Sun waking up. This could mean the next few decades—think 2030s to 2050s—will see stronger solar cycles than we’ve had recently.
This matters because we’re hooked on technology—like satellites for GPS, internet, and weather apps, or power grids that keep our homes lit. When the Sun gets wild, it can zap these systems. Plus, it can make the northern lights brighter or even tweak our weather a bit. Knowing what’s coming can help us get ready.
What Could Happen?
If the Sun’s entering a high-energy phase, here’s what might happen and why we should care:
Tech Troubles: Solar storms can fry satellites, mess up GPS, or even knock out power. Back in 1989, a storm shut off electricity for millions in Canada. A busier Sun means more risks for our phones, flights, and lights.
Space Risks: Astronauts on future Moon or Mars trips (like SpaceX or NASA’s plans for the 2030s) could face more radiation from solar storms, making missions trickier.
Awesome Auroras: More solar activity means brighter northern and southern lights, maybe visible in places like the northern U.S. or central Europe.
Small Climate Changes: The Sun might slightly change rainfall or winds in some areas, but it’s a small effect compared to climate change from pollution.
Why Should You Care?
The Sun’s 100-year cycle isn’t just for scientists—it’s about your life. A more active Sun could mean spotty GPS when you’re driving, power outages during storms. It’s like checking the weather forecast, but for space, so we can keep our tech running and enjoy the show. Scientists are watching the Sun closely with satellites and new tools, and they’re getting better at predicting what’s next.
The 100-year solar cycle is heating up, and 2025 marks the start of a high-energy phase that’ll bring storms and challenges.
