It's a frightening scenario: the lights go out, gas pumps don't work, food deliveries stop -- even pumps that deliver water to your home won't work anymore, to say nothing of cellular phones, computers and tablets.
It's not a movie script, it's a warning about what life would be like without electricity from those who keep a close eye on the sun, including scientists right here in our state at Kitt Peak.
Here in the valley of the sun, we like to think we know everything about our closest star. It shines enough.
"What I specialize in is ground bases observation of sun spots."
Dr. Matthew Penn studies the sun and sun spots at Kitt Peak National Observatory from inside the McMath-Pierce solar telescope built into the side of a mountain southwest of Tucson.
"Sunspots are regions that have intense magnetic fields and those magnetic fields are what can cause trouble here on the Earth," said Penn.
You may have learned about sunspots in school -- those black spots on the surface of the sun.
"The reason that sunspot is dark is that these regions of the sunspot have very strong magnetic fields," said Penn.
Sunspots can trigger enormous solar flares, sometimes called solar storms.
If they head towards Earth, these waves of solar wind interact with the planet's magnetic field. Northern lights will glow, but these storms can also knock out radios, disrupt satellite communication, your cable TV, even turn out the lights.
"That material can travel down through the solar system and have an impact on the Earth or any other planet or spacecraft that's in the way," said Penn.
Those effects can be devastating and it's happened before.
"In 1989, Canada suffered a big power failure and I think it was three days power was shut down to millions of people because of a solar flare," said Penn.
The biggest on record happened in the 1800s when our electronic technology was still primitive. Telegraph lines were the only way people could communicate over long distances.
"But the currents that were caused in those lines by the changes in the Earth's magnetic field from the flare actually burned down some telegraph offices," said Penn.
Every 11 years or so, the sun starts generating more sun spots and more solar storms. We're in a peak period right now.
"We look at the disk on the sun and try to study small structures that we see," said Penn.
On the day we visited Dr. Penn in August, only one sunspot could be seen between the clouds passing overhead, but one is all it would take.
"This sunspot is about five times the size of the planet Earth and has the potential to release a powerful solar storm if the magnetic field changes in a dramatic way," said Penn.
James Hunt, a Senior Engineer with the Salt River Project says, "One of the key things we are concerned about is damage to large transformers like the big boxes you see in the background."
We met Hunt at a substation in Tempe.
"This is called Brandow Substation and it's one of our major delivery sites which we have about a dozen around the valley," he said.
Hunt knows all about the threat posed by solar storms.
"It's possible with the direct current induced by one of these geomagnetic storms to have damage to the transformer," he said.
But SRP, like other power companies nationwide, has taken steps to minimize the risk.
"We install protective relaying to prevent damage to these boxes," said Hunt.
Besides, most solar storms impact only Earth's polar regions. They are not seen as a big threat down here.
"We are really a lower probability to have an affect of a solar storm," said Hunt.
But scientists warn a solar storm, if it's big enough, can knock out power anytime, anywhere.
"Once the magnetic field of the Earth starts to change, that affects things on the day side and night side of the planet, so the effects are global," said Penn.
And the damage could be a life changing event. Severe solar damage to SRP's power grid could take more than a year to fix.
"In a time of less strong demand, it might be as little as 10 to 12 months. In a time when electrical demand is expanding quickly, it might be as much as 18 months or more," said Hunt.
18 months or more?
That's a long time to go without air conditioning. Gasoline pumps wouldn't work, no power to cellular towers means your cell phone won't work either.
"It's incredible how much we depend on power these days -- the refrigerator in your house is one example and when you start to lose food..then it's a problem," said Penn.
A short elevator ride and a long stair climb later, we're at the top of the McMath-Pierce telescope -- 7,000 feet high. It's big mirror is still the third largest of any land based solar observatory, 50 years after it was built.
"And we have two other telescopes which are also large compared to other solar facilities," said Penn.
For now, the McMath-Pierce solar telescope will keep watching, just in case. It's scheduled to close in 2016 when a new solar observatory opens on Maui. But 50,000 people a year still visit Kitt Peak and the big telescope's job isn't finished yet.
"The McMath-Pierce is an international icon in the solar physics world. We have astronomers from all over the planet come here and study the sun in ways that no one else has with to improve the technology to understand our nearest star," said Penn.
Dr. Penn says a solar flare can take from one to five days to strike Earth, so telescopes like the one on Kitt Peak and NASA satellites in orbit also serve as an early warning system.
McMath-Pierce Solar Telescope