"We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras."
Sibeck likens them to ropes because the magnetic fields in question are twisted much like rope thread.
Solar wind particles flow along the ropes in whirligig trajectories leading from the sun to Earth.
Which brings us back to spring.
Magnetic connections between the Sun and Earth are more favourable in springtime.
It's a matter of geometry: As Earth orbits, the combination of the 23-degree polar tilt plus orbital motion makes the poles seem to wobble from a solar point of view. And around the time of the equinox, Earth's magnetic field is best oriented for "connecting-up" with the sun, and this opens the door for solar wind energy to flow in and spark the Northern Lights.
As there are two equinoxes in spring and autumn, both with similar magnetic geometry, autumn is aurora season, too.
Geomagnetic disturbances are almost twice as likely in spring and autumn as opposed to winter and summer, according to historical records.
THEMIS is on a two-year mission to explore Earth’s magnetic field.
"With five satellites, we can map the complex ebb and flow of energy during geomagnetic storms better than any single satellite ever could," points out Angelopolous. "There's no telling what we might learn."
View our aurora gallery here…back to page 1
Have you ever wanted to travel to see the Northern Lights? If so, then you might find this interesting.
