Watch what scientists have just recorded for the first time: explosive space weather from start to finish.
The sun regularly spews forth bursts of particles and magnetic fields known as a coronal mass ejection, or, CME. A CME starts small in solar terms—just a few hundred times the size of the Earth—but it grows and changes as it travels toward the edges of the solar system. Scientists have been observing these events with satellites for decades, but tracking the details of an ejection's growth from original seed to complex structure near Earth has been more challenging. In fact, scientists recently used three NASA spacecraft—STEREO-A, WIND and ACE—to create the first visual record of a CME's path from the sun to the Earth. The orbiting instruments captured the CME's birth on Dec. 12, 2008 at the sun's surface, its exponential growth and its ultimate engulfing of the Earth about three days later. These ejections are common but large solar events can alter our magnetic atmosphere to such a degree that communications signals from GPS or telecom satellites are temporarily degraded beyond recognition. This visualization allowed scientists to watch how features early in the CME ultimately create the form seen closer to Earth, with a bright leading edge and trailing evacuated cavity.