The northern lights explained

The snapping of Earth’s electrical field causes a release of electromagnetic particles that cause the dancing northern lights.

There has never been a time in my memory that I have not been stopped in my tracks by a photograph of the Aurora Borealis. One of the most interesting searches I can think of on the computer are for photos of the Northern Lights, geomagnetic phenomena, electrical storms and other curious phenomena that have forever caused humans to marvel.

This morning the NYTIMES has an article called “Scientists Find Trigger for the Northern Lights” that reports on recent findings beyond what we already know: the beautiful light shows are caused by charged particles emanating from the sun interacting with the Earth’s magnetic field.

A NASA team of researchers on mission called THEMIS devoted to understanding space weather has determined that a snapping of the electrical field causes a release of electromagnetic particles that cause the dancing lights. The NYT article has a multimedia animation showing the effect called “Substorms in Space.”

UC Berkley gives a detailed report on THEMIS mission, and an interesting announcement of the satellite mission launched in 2007 can be found here. It’s worth going to the original news item in SCIENCE, published July 24, 2008, to read more about it. “Shedding Light on Nighttime Brights” explains that the Earth and sun are locked in an eternal magnetic dance, with particles spewed from the sun being deflected or subsumed by the Earth’s magnetic sphere. The phenomenon of lights seen at polar regions starts with the collection of particles that stretch, bend, and eventually snap our magnetic field. The snapping causes the release of electromagnetic energy we see as lights. More than just a pretty show, the energy in these substorms is enough to cause disruption of our satellites and communication systems on earth.

With this research, NASA hopes to find ways to more accurately predict – and then prepare for – the storms that we enjoy visually as the Northern Lights.

Beverly Spicer