A significant expansion of a weak spot in Earth’s magnetic field is raising concerns among scientists. This area, known as the South Atlantic Anomaly (SAA), has been monitored by the European Space Agency’s Swarm satellites since their launch in 2014. Recent studies indicate this weak region is growing larger, posing potential risks to orbiting satellites and astronauts.
Growth of the South Atlantic Anomaly
The Swarm satellites have revealed that the SAA has expanded by nearly half the size of continental Europe over the last decade. Specifically, it has increased by almost 1% of Earth’s total surface area since 2014. The weakest point within the SAA now measures about 22,094 nanoteslas, a notable decrease of 336 nanoteslas since 2014.
Comparison with Other Regions
Interestingly, the geomagnetic field’s strength varies across different regions. The intensity over northern Canada exceeds 57,000 nanoteslas but has decreased by 0.65% in area since 2014. Meanwhile, a strong field region in Siberia has grown, with its strength increasing to 61,619 nanoteslas—a rise of 260 nanoteslas.
- South Atlantic Anomaly: Weakest point at 22,094 nanoteslas.
- Canada: Strong region greater than 57,000 nanoteslas.
- Siberia: Increased to 61,619 nanoteslas.
Potential Risks to Spacecraft and Astronauts
As the SAA grows, both satellites and astronauts face increased exposure to solar radiation. This uptick in radiation could lead to malfunctions in satellites and an elevated cancer risk for astronauts. The Swarm researchers highlighted that satellites could experience higher rates of charged particles when passing through this weak field region.
Protective Measures for Spacecraft
To mitigate these risks, researchers suggest that future spacecraft should be designed to withstand greater levels of solar radiation. “As the weakness is growing,” noted geomagnetism researcher Chris Finlay, “future missions should account for the larger affected area.”
Understanding the Geomagnetic Field
Earth’s geomagnetic field is generated by a rotating core of molten iron located about 2,900 kilometers beneath the surface. The intensity of this field ranges from 22,000 to 67,000 nanoteslas, considerably weaker than common magnets found in households.
While the changes in the SAA were anticipated based on earlier observations, the researchers emphasize the importance of ongoing high-quality geomagnetic measurements. These insights are crucial for understanding the dynamics of Earth’s magnetic field and its implications for space exploration.
Conclusion
The study, published in the journal Physics of the Earth and Planetary Interiors, confirms that monitoring Earth’s magnetic field remains essential. Further investigations will be required to uncover the mechanisms behind these fluctuations, particularly as the weak regions expand over time.
