: Most coronal mass ejections
(CMEs) have lost enough energy by the time they reach Earth that they have little more effect than the normal solar wind. Now, evidence from a series of CMEs in 2012 has shown that the eruptions can merge and sustain higher levels of energy out past Earth's orbit. Ying Liu of the National Space Science Center in Beijing and his colleagues used data from the STEREO-A
spacecraft, which recorded three CMEs over a five-day period that merged into a single large, electromagnetic storm. If the eruptions had been directed toward Earth, the resulting wave of particles would have had 10 times the magnetic strength of a normal CME when it reached Earth. That would likely have been strong enough to short-circuit power grids and disrupt satellites.