The powerhouse energy source of Earth’s northern lights, or aurora borealis, has been discovered. What’s the cause of it, the source, the birds and the bees explanation? The culprit is Earth’s own magnetic field, combined with strong solar storms generated by the sun, according to the co-author of a recent study, University of California’s Vassilis Angelopoulos.
The beautiful, colorful displays of lights in the Earth’s northern hemisphere over the planet’s polar ice caps are actually cosmic storms. Knowing more information about the northern lights, the cosmic storms, might help enable scientists to better predict disruptions caused by these “storms” which can interfere with the world’s power systems. They could also, with their bursts of radiation, expose astronauts to potentially dangerous levels of it.
The role of the sun in the Northern Lights
Charged particles from solar storms get slammed into our planet’s magnetic field on a fairly regular basis. This sends high-energy particles into the Earth’s “magnetotail.” The magnetotail is a part of our planet’s magnetic field that resembles a long tail. These particles then return back to the Earth as geomagnetic storms.
Particles and plasma stream from solar winds at extremely fast speeds, which can reach as high as 1 million mph, according to Angelopoulos.
This winds from the sun flaring out deforms the magnetic field of our planet. The solar winds, on whichever side of the Earth faces the sun at the time, compress the magnetic field. This compression is what creates the Earth’s long magnetotail which can be seen on the night side of our planet.
The Earth’s magnetic field has a portion of that energy transferred to it. Then, this portion of energy is gets absorbed by the Earth’s magnetic storms, causing the swirling, colorful aurora borealis, and also the Southern Lights, or aurora autralis.
According to an interview Angelopoulous gave to Space.com, these lights can, during times of magnetic storms, “light up the entire night sky all the way down south to Hawaii.”
In 1859, the so-called Carrington Event, a very large solar storm, succeeded in shutting down telegraphic lines all around the world. That storm, and others since, have made it a high priority of scientists to predict these occurrences.
NASA THEMIS mission monitoring the storms and Northern Lights
NASA has been involved in monitoring the magnetic storms and the auroras, using five spacecraft that have traveled through the magnetic field of the Earth and have also orbited the moon. These spacecraft have measured such things as the Earth’s electric and magnetic fields, and plasma changes.
Two of these NASA probes detected the Earth’s magnetotail. According to THEMIS project scientist David Sibeck (who wasn’t involved in the study), the stream of solar wind’s particles which hit the Earth’s magnetic field strengthens it. Finally, the magnetic field can’t hold any more energy. The energy is released in an explosive burst, and that is “the birds and the bees,” of how geomagnetic storms are formed.
Written by: Douglas Cobb