This animation shows how the THEMIS mission observed auroral brightening resulting from a substorm in which solar particles and energy disturbed Earth’s magnetic field. The THEMIS orbits are shown in golden lines, and the Earth’s magnetic field lines are shown in blue. When solar material strikes the magnetosphere, the day side is pushed inward, while the back end magnetotail stretches out away from the Sun. When the stretched magnetotail finally snaps back, it starts to vibrate like a plucked guitar spring. As that happens, electrons in near-Earth space rapidly move toward the Earth’s poles along the magnetic field lines. As the electrons enter the upper layers of the atmosphere, they interact with oxygen and nitrogen atoms, releasing photons to create the aurora.
Video Credit: NASA