Earth's Magnetosphere
Earth's magnetic field generates an invisible bubble around our planet, called the magnetosphere. The magnetosphere is a bit like a magnetic shield that surrounds the planet, protecting us from many types of radiation from the Sun.
The Sun releases a constant stream of electromagnetic and particle radiation, called solar wind. This solar wind flows around Earth’s magnetosphere, drawing the field out into a comet-like tail.
In this visualization of Earth's magnetosphere the curving outer region, shown in red, indicates where a supersonic shock wave, called the bow shock, occurs due to solar wind colliding with Earth's magnetic field. The solar wind stretches the magnetosphere as it passes by the Earth, giving it a comet-like shape.
NCAR High Altitude Observatory (HAO)
Earth's Dipole Magnetic Field
Earth’s magnetic field is generated from the movement of molten iron in the Earth’s outer core, creating powerful electric currents. These currents orient around magnetic field lines between the poles that extend beyond Earth’s atmosphere, as shown in the diagram to the right. The magnetosphere can be visualized as magnetic field lines produced by a giant bar magnet, with oppositely charged ends, tilted about 11° from Earth’s rotational axis. One magnetic pole is located in northern Canada, and the other pole is located in Antarctica. The magnetic field above the poles extends far into space and shields the Earth from many of the energetically charged particles coming from the Sun and more distant sources in the galaxy.
The Magnetosphere Protects Earth's Atmosphere
The magnetosphere deflects much of the solar particles and energy that stream towards Earth at all times. Without the magnetosphere, Earth's layered atmosphere would deteriorate due to the constant bombardment of solar wind. And without our uniquely layered atmosphere, which protects us from harmful ultraviolet (UV) radiation and traps heat, life on Earth wouldn't be possible.
Some of the solar wind breaks through and becomes trapped in the magnetosphere. Plasma, or charged gas, enter the magnetosphere through funnel shaped openings at the poles, resulting in colorful auroras that encircle the magnetic poles. During periods of increased solar activity, severe space weather can harm astronauts, damage satellites, and disrupt communication systems orbiting Earth. Space weather can also damage power grids on Earth’s surface. Longer-term variations in solar magnetic activity can also affect Earth’s climate and space environment.