A hole in the Earth’s magnetic field has been identified: what we know

NASA is actively monitoring a strange anomaly in the Earth’s magnetic field: the US space agency has in fact identified a gigantic region that has a lower magnetic intensity in the skies of the planet, at a height of about 200 kilometers, which extends between the South America and Southwest Africa. This phenomenon has intrigued and worried scientists for years and has been dubbed the South Atlantic Anomaly (SAA). NASA’s satellites and spacecraft are particularly vulnerable to the weakening of the magnetic field resulting from exposure to high-energy protons emanating from the Sun.

The anomaly can create problems in spacecraft and satellites

The South Atlantic anomaly has been likened by experts to a “dent” in Earth’s magnetic field, generally not affecting life on Earth, but the same cannot be said for spacecraft, including the International Space Station, which pass directly through this zone as they circle the planet in low-Earth orbit. During these crossings, the reduced intensity of the magnetic field inside the SSA can short-circuit the technological systems on board the satellites or make their operation more difficult when they are hit by particles from the Sun. An anomaly that carries the risk of causing a significant data loss or even permanent damage to key satellite components as operators have to shut down vehicle systems before they enter the SAA zone. To deal with these problems, NASA constantly monitors the hole in the magnetic field.

The studies that are shedding light on the strange phenomenon

Studying this area, however, also become a great opportunity to investigate a complex and difficult to understand phenomenon. Although there are still many scientists claiming that it is not yet possible to fully understand the anomaly and its implications, new research is slowly shedding light on the phenomenon. For example, a study by NSASA heliophysicist Ashley Greeley in 2016 revealed that the SAA is drifting slowly in a northwesterly direction. Even more surprising, the phenomenon appears to be about to split in two, as researchers discovered in 2020: the hole would in fact be about to split into two distinct cells, each of which has a separate center of minimal magnetic intensity. Another study published in July 2020 suggested that the phenomenon is not a freak event of recent times, but is recurring and could be present in Earth’s skies from 11 million years ago. If this study is confirmed, it would indicate that the South Atlantic anomaly has nothing to do with a possible magnetic field reversal of the entire planet, a phenomenon that occurs with a frequency of hundreds of thousands of years at a time.