Last night there was some excitement about coronal mass ejection (CME) from the Sun hitting the earth and sparking northern lights. It was, apparently, a big fizzle, as Spaceweather.com explains:
Every CME brings with it some magnetic field from the sun. If that magnetic field points south, it opens cracks in Earth’s magnetic field, allowing solar wind to flow inside and fuel auroras. On the other hand, if the CME’s magnetic field points north, it seals cracks in Earth’s magnetic field, blocking the solar wind and quenching storms.
This CME brought a storm-killing north magnetic field. So, even though the velocity of the solar wind in the CME’s wake flirted with a high value of 600 km/s, it was ineffective in causing geomagnetic storms and auroras.
Learning something new every day!
