By Christine Gabrielse
Some planets have magnetic fields that act as invisible force fields against the solar wind and the sun’s radiation, called magnetospheres. Although their natural shape is more like a doughnut with the planet at the center, the solar wind is such a strong force that magnetospheres are pulled backwards like a windsock into what we call a magnetotail. The energetic particles carried by the solar wind can sneak into the magnetotail and fill it with energy until an explosive phenomena (“magnetic reconnection”) flings those energetic particles towards the planet. The result is beautiful and dangerous: as the energy hits the planet and creates aurora across the sky, it may also strike orbiting satellites and render them useless. If communication satellites went down at Earth, we could be without GPS and cell phones! I am studying the phenomena that happen when these energetic particles are flung towards a planet in an effort to understand just how they are transported through the magnetotail.
(credit SVS/GSFC, J. Raeder/UNH, V. Angelopoulos/UCLA)