Surprise Solar Storm Sparks Stunning Auroras and Twitter Frenzy.

The strongest solar storm in nearly six years hit the Earth on Friday, causing auroras visible as far south as New Mexico and forcing Rocket Lab to delay a launch. The storm was marked as a grade 4 on the 5-grade scale used by the US National Oceanic and Atmospheric Administration to assess the severity of space weather events. The storm was triggered by a "stealth" coronal mass ejection which is difficult to detect, catching space weather forecasters by surprise. Strong geomagnetic storms can also affect spaceflight as they increase the density of gases in Earth's upper atmosphere, thereby increasing the drag on satellites and other spacecraft.