There's a good chance our sun could emit a 'superflare' that fries the world's electronics sometime in the next 100 years, scientists say.
Until now, it was believed stars of a certain age - like our sun - don't let off destructive plumes of high-energy radiation, leaving that to younger stars.
But a new analysis of data collected by NASA's Kepler telescope should have anyone that relies on electricity worried.
"Our study shows that superflares are rare events, said Yuta Notsu of the University of Colorado Boulder, who led the research.
"But there is some possibility that we could experience such an event in the next 100 years or so."
It could "disrupt electronics across the globe, causing widespread blackouts and shorting out communication satellites in orbit", the researchers said in a statement.
Kepler looked at dozens of stars that resemble our sun, which is about 4.6 billion years old - halfway through its life.
"When our sun was young, it was very active because it rotated very fast and probably generated more powerful flares," said Notsu. "But we didn't know if such large flares occur on the modern sun with very low frequency."
They found young stars let off a superflare about once a week, and stars like our sun, once every few thousand years.
"If a superflare occurred 1000 years ago, it was probably no big problem. People may have seen a large aurora. Now, it's a much bigger problem because of our electronics."
Notsu told Astronomy magazine a superflare nowadays would result in "large-scale blackouts, satellite communication failure, and strong radiation in space" which would damage satellites we rely on.
"This topic should [start to be considered] seriously from now on."
Normal-sized flares are fairly common, and can happen several times a day.
In 2012, a coronal mass ejection - similar to a flare, but at extreme high speeds - narrowly missed the Earth by just nine days. If it had hit the Earth, one study found it could have caused NZ$4 billion in damage to the US, let alone the rest of the world.
A blast in 1859 knocked out the US telegraph system.