Scientists have discovered that the Sun is behaving in mysterious and unexpected ways after listening to its 'heart'. A new study reveals that something has changed in the Sun's internal rhythm over the past 40 years, with potential consequences for life on Earth.
Solar Cycles and Space Weather
The Sun operates on an 11-year cycle, alternating between periods of high and low activity. During active phases, the Sun releases solar flares and coronal mass ejections that can generate dangerous solar storms. These storms have the capacity to disrupt satellites, power grids, and communications on Earth.
Listening to the Sun's Interior
Researchers used sound waves within the Sun to probe its interior structure. This technique, known as helioseismology, allows scientists to monitor changes deep beneath the solar surface. The study, led by Bill Chaplin from the University of Birmingham, found that the Sun appears to be entering a 'different mode of behaviour'.
Key Findings
In addition to the familiar 11-year cycle, the team identified longer-term structural changes. The study suggests that solar magnetic activity is being pushed into a layer just below the visible surface, and this layer is becoming progressively shallower over time.
"The Sun has its own 'active biorhythm' creating rising and falling magnetic activity that shapes space weather. However, traditional surface measures don't capture the full story – that the Sun may be entering a different mode of behaviour unfolding over decades," said Chaplin.
"We have uncovered evidence of systematic changes in the solar activity cycle. Crucially, magnetic activity is becoming more tightly confined near the surface with each cycle. This is the first such discovery and would have been impossible without the long BiSON observations."
Implications for Future Research
The researchers emphasise that more work is needed to understand the Sun's current cycle and the internal processes driving these changes. "We discovered that the relationship between internal solar oscillations and surface activity has evolved over the past few cycles," said Sarbani Basu from Yale University.
"This trend cannot be explained simply by weaker magnetic fields. Instead, it indicates a structural reorganisation of how the Sun's magnetic activity is stored beneath the surface."
The findings highlight the importance of continuous monitoring of the Sun to predict space weather and protect technology-dependent societies. The study was based on decades of data from the Birmingham Solar Oscillations Network (BiSON).
