The forces in the core and the tilt of the magnetic axis together produce the anomaly, the area of weaker magnetism – allowing charged particles trapped in Earth’s magnetic field to dip closer to the surface. These evolutions in the field, which happen on a similar time scale to the convection of metals in the outer core, provide scientists with new clues to help them unravel the core dynamics that drive the geodynamo.These dynamic processes in the core bounce outward to the magnetic field around the globe, creating the SAA and other characteristics in the near-Earth environment including the tilt and drift of the magnetic poles, which are shifting over time.The magnetic field fluctuates in both space and time along with the core motion as a result of intricate geodynamic conditions both inside the core and at the boundary with the solid mantle above. These churning metals act like a massive generator, called the geodynamo, creating electric currents that produce the magnetic field.That’s because the field originates from Earth’s outer core: molten, iron-rich, and in vigorous motion 1800 miles below the surface.But unlike a bar magnet, the core magnetic field is not perfectly aligned through the globe, nor is it perfectly stable.The flow of molten metals within its outer core.Įarth is a bit like a bar magnet, with north and south poles that represent opposing magnetic polarities and invisible magnetic field lines encircling the planet between them.The South Atlantic Anomaly arises from two features of Earth’s core: In fact, scientists only detect them using sensitive instruments inside satellites and spacecraft.The radiation belts themselves are so dilute that astronauts don’t even see or feel them when they are outside in their spacesuits.Van Allen, the American physicist who designed the instruments on board Explorer 1, the first spacecraft launched by the United States.Īlthough images of the Van Allen radiation belts make them look visible and colorful, this is actually just a representation. The Van Allen radiation belts were discovered in 1958 by James A. The inner belt results from interactions of cosmic rays with Earth’s atmosphere. The outer belt is made up of billions of high-energy particles that originate from the Sun and become trapped in Earth’s magnetic field, an area known as the magnetosphere. It surrounds Earth, containing a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.These particles are captured by and held around a planet by that planet’s magnetosphere. Van Allen belt Courtesy: NASAĪ Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind. The recent data shows the anomaly’s valley, or region of minimum field strength, has split into two lobes, creating additional challenges for satellite missions. However, recent observations and forecasts show that the region is expanding westward and continuing to weaken in intensity.Currently, the SAA creates no visible impacts on daily life on the surface.In turn, this anomaly also causes technical disturbances in satellites and spacecraft orbiting Earth.
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