![]() Though the colors in the second image are just as bright as the first, note that the greatest changes were plus or minus 100 nanotesla in a field that reaches 60,000 nanotesla. The second image shows changes in that field over the same period. It also provides the basis for navigation with a compass.īased on data from Swarm, the top image shows the average strength of Earth’s magnetic field at the surface (measured in nanotesla) between January 1 and June 30, 2014. Generated by the motion of molten iron in Earth’s core, the magnetic field protects our planet from cosmic radiation and from the charged particles emitted by our Sun. Launched in November 2013 by the European Space Agency (ESA), the three-satellite Swarm constellation is providing new insights into the workings of Earth’s global magnetic field. That might be somewhat important if you use a compass, or for certain animals like birds, fish and sea turtles, whose internal compasses use the magnetic field to navigate. This causes the location of Earth’s magnetic north and south poles to gradually shift, and to even completely flip locations every 300,000 years or so. Since the forces that generate our magnetic field are constantly changing, the field itself is also in continual flux, its strength waxing and waning over time. You can learn more about Earth’s magnetosphere here. Our magnetosphere plays the role of gatekeeper, repelling these forms of energy that are harmful to life, trapping most of it safely away from Earth’s surface. Generated by powerful, dynamic forces at the center of our world, our magnetosphere shields us from erosion of our atmosphere by the solar wind, particle radiation from coronal mass ejections (eruptions of large clouds of energetic, magnetized plasma from the Sun’s corona into space), and from cosmic rays from deep space. Credit: NASA Goddard's Conceptual Image Lab/Greg ShirahĮarth is surrounded by an immense magnetic field, called the magnetosphere. This solar wind is always passing by Earth. A constant outflow of solar material streams out from the Sun, depicted here in an artist's rendering. ![]()
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