NASA studies what dent in magnetic field could mean

A dent in Earth's magnetic field, which is currently small but described by NASA as "evolving," is being observed by the agency's researchers, according to an Aug. 17 press release from NASA.

The dent is a result of Earth's magnetic axis and the molten metals that flow through its outer core, which turn the planet into somewhat of a "bar magnet" with north and south poles. But the instead of a perfectly aligned core magnetic field through the globe, it's isn't perfectly aligned or stable. The liquidized metals churning in unpredictable motions result in electric currents that fluctuate. 

"Earth's magnetic field acts like a protective shield around the planet, repelling and trapping charges particles form the Sun," NASA said in the press release. 

The agency has observed an abnormally weak spot in the magnetic field over South America and the southern parts of the Atlantic Ocean; the spot is referred to as the South Atlantic Anomaly (SAA), which lets particles "dip closer to the surface," according to NASA.

The resulting consequence can reportedly be an array of problems for the planet's satellites, including malfunction of satellite computers and data collectors, which is "a key reason why NASA scientists want to track and study the anomaly."

The agency additionally wants to monitor the SAA's potential impacts on the planet's magnetic fields within the globe and the atmosphere. 

"Currently, the SAA creates no visible impacts on daily life on the surface," NASA said in the press release. "However, recent observations and forecasts show that the region is expanding westward and continuing to weaken in intensity. It is also splitting – recent data shows the anomaly’s valley, or region of minimum field strength, has split into two lobes, creating additional challenges for satellite missions."

Weija Kiang, a geophysicist and mathematician in Goddard's Geodesy and Geophysics Laboratory, said the SAA is a sign of weakening dominance of the dipole field. 

“More specifically, a localized field with reversed polarity grows strongly in the SAA region, thus making the field intensity very weak, weaker than that of the surrounding regions," she said in the press release. 

Bryan Blair, mission deputy principal investigator and instrument scientist for the International Space Station (ISS), said in the release that when the ISS passes through the anomaly instruments aboard the station are reset, causing a couple hours of lost data. 

NASA said that the SAA is allowing researchers new opportunities to further understand the planet's core and to study how its electrical dynamics influence other systems. 

"By tracking this slowly evolving 'dent' in the magnetic field, researchers can better understand the way our planet is changing and help prepare for a safer future for satellites," Blair said in the press release.