Imminent disruption is predicted for satellites, power systems and even mobile phones because of a solar storm.
It comes from one of the largest groups of sunspots seen for years. On Thursday superhot gas erupted above them.
The event, called a Coronal Mass Ejection, sent 10 billion tonnes of superhot gas speeding towards Earth.
As well as communication blackouts, aurorae – polar lights – may be seen from mid-latitudes as the gas arrives.
“10 billion tonnes of Superhot gas”? Speeding our way? I left the car in the sun yesterday, and when I got into it in the late afternoon, the thermometer said 111 degrees Fahrenheit (ie 43.8 Celsius). Isn't that hot enough already?