From Earth, we only ever see half of the sun.
The other half—the far side—is always hidden from view. But what happens there still matters.
Powerful activity forming on the far side can rotate toward Earth and trigger solar storms that affect satellites, communication systems and power grids.
Now, scientists have developed a new way to better understand what is happening on that hidden side.
In a study published in Scientific Reports, researchers led by Amr Hamada have shown how to map not just the location of active regions on the sun’s far side, but also their magnetic structure.
For years, scientists have used a method called helioseismology to study the hidden half of the sun. This technique works by “listening” to sound waves that travel through the sun’s interior.
These waves bounce around inside the sun and carry information about what lies beneath the surface.
By studying how the waves move, researchers can detect large active regions, such as sunspots, even when they are out of sight.
However, until now, this method could not reveal one key detail: magnetic polarity. This describes the direction of magnetic fields, which determines how solar activity behaves.
Some magnetic structures can lead to strong eruptions, while others are less dangerous. Without this information, it has been difficult to fully predict the impact of solar events.
The new breakthrough comes from analyzing subtle patterns in the sound waves. The team used data from the Global Oscillation Network Group, a worldwide system of solar telescopes that continuously monitors the sun.
By studying tiny changes in the waves, known as phase shifts, the researchers found clues about how magnetic fields are arranged in hidden regions.
Using this information, they were able to estimate the magnetic polarity and orientation of far-side active regions. In effect, they created magnetic maps of parts of the sun that cannot be seen directly. This is a major step toward building a complete picture of the sun’s magnetic field.
This advance could have important real-world benefits. The sun rotates once every 27 days, meaning activity on the far side can move into view and affect Earth within days. By knowing more about these regions earlier, scientists can improve space weather forecasts and give better warnings of potential disruptions.
Such warnings are increasingly important in a world that depends on technology. Solar storms can damage satellites, interfere with GPS signals, disrupt communications and even affect power systems on the ground. A more complete understanding of the sun’s magnetic behavior could help reduce these risks.
Although the far side of the sun remains invisible to telescopes, this research shows that it is not beyond our reach. By “listening” to the sun’s internal vibrations, scientists are uncovering hidden magnetic patterns that shape its most powerful activity.
With further improvements, this method could one day allow researchers to create a full, continuous map of the sun’s magnetic field—including the half we can never see directly.
Source: National Solar Observatory.
