Washington ? When the sun sneezes, it’s Earth that gets sick.

It’s time for the sun to move into a busier period for sunspots, and while forecasters expect a relatively mild outbreak by historical standards, one major solar storm can cause havoc with satellites and electrical systems here.

Like hurricanes, a weak cycle refers to the number of storms, but it only takes one powerful storm to create chaos, said scientist Doug Biesecker of the National Oceanic and Atmospheric Administration’s space weather prediction center.

A report by the National Academy of Sciences found that if a storm as severe as one in 1859 occurred today, it could cause $1 trillion to $2 trillion in damage the first year and take four to 10 years to recover.

The 1859 storm shorted out telegraph wires, causing fires in North America and Europe, sent readings of Earth’s magnetic field soaring, and produced northern lights so bright that people read newspapers by their light.

Today there’s a lot more than telegraph lines at stake. Vulnerable electrical grids circle the globe, and satellites now vital for all forms of communications can be severely disrupted along with the global positioning system. Indeed, the panel warned that a strong blast of solar wind can threaten national security, transportation, financial services and other essential functions.

While the most extreme events seem unlikely this time, there will probably be smaller scale disruptions to electrical service, airline flights, GPS signals and television, radio and cell phones.