TRANSCRIPT - THEMIS Discovers Biggest Breach of EarthÕs Magnetosphere


NASAÕs THEMIS mission has overturned a longstanding belief about the interaction between solar particles and EarthÕs magnetic field.


The EarthÕs magnetic field is like a giant bar magnet. This magnet forms a protective field around the Earth shielding us from the solar wind that is constantly streaming towards Earth. This shield is called the magnetosphere.


ÒThe solar wind is primarily comprised of protons and electrons. TheyÕre streaming outwards from the sun at up to a million miles per hour and theyÕre constantly bombarding EarthÕs magnetic field. WeÕre shielded by our EarthÕs magnetic field most of the time, however a small fraction of the solar wind particles get in to the EarthÕs magnetic field, are energized and become the EarthÕs radiation belts, which can damage spacecraft and harm astronauts.Ó


But the sun has a magnetic field of its own as well, which the solar wind carries outwards towards Earth. And the THEMIS spacecraft fleet recently observed that twenty times more solar particles get in to the EarthÕs magnetosphere when the sunÕs magnetic field aligns with that of the Earth, than when they are pointed in opposite directions.


ÒIn the past researchers found that the energy from the sun get in to the EarthÕs magnetic field at times when the EarthÕs magnetic field points southward. Here we found that when the particles get in the plasma, the particles from the sun get in to the EarthÕs magnetic field when the sunÕs magnetic field points northward. For a long time people have known that the location where particles and energy get in to the EarthÕs magnetic field depend on the orientation of the sunÕs magnetic field. But they just hadnÕt realized how many particles get in for the northward orientation of the sun.Ó


So, what do these new finding mean for us here on Earth? Well, with this new information, scientists can make better predictions about when solar storms will be severe. Meaning we can better prepare for the power outages, satellite damage and other problems that these storms can often cause.