A severe geomagnetic storm sparked by a solar flare swept the Earth Monday and a second is forecast to strike late Wednesday afternoon.
While that’s U.S. East Coast time, the impact has the potential to be worldwide -- everything from power being disrupted to radios blacking out to global positioning systems going a little off-course.
Monday’s event, which was still winding down Tuesday, doesn’t seem to have caused any failures or forced planes to reroute, according to industry statements. It registered as a G4 storm on the U.S. Space Weather Prediction Center’s five-step Geomagnetic Storm scale and touched off auroras that were visible across northern Asia, Europe and parts of Canada and the U.S.
It also registered an S3 and an R2 on the Solar Radiation and Radio Blackout scales. Yes, there are three different scales for measuring the severity of a solar storm.
The Geomagnetic Scale gives us an indicator for the nice light shows in both the Northern and Southern hemispheres and the power that can knock out electricity to your house. A G5 storm could be a catastrophic event, with the complete collapse of some power grids, satellite navigation disrupted for days and “hundreds of amps” of current in pipelines.
Solar radiation can fry satellites, expose airline crews and passengers in high latitudes to radiation and keep astronauts from venturing out on space walks.
The radio blackout component involves pretty much what you’d think. The effects of this are on the sunlit side of the Earth.
Using those scales as a guide, it’s apparent that Monday’s event posed the largest threat to grid operators and pipeline companies and not as much to airlines.
So what will hit the Earth on Wednesday?
We’ll know for sure about 30 minutes before it gets here.
“It looks like we’ll possibly be in a much similar situation,” said Brent Gordon, operations officer at the space weather center in Boulder, Colorado.
Using a coronagraph, forecasters on Earth can get a pretty good idea of the size of the sun’s the coronal mass ejection and extrapolate its potential from there. The CME is an explosion of magnetic fields and plasma from the sun’s atmosphere.
“You get a ballpark idea of how much matter is there,” Gordon said.
However, it’s only when the CME reaches NASA’s ACE satellite, parked 1 million miles (1.6 million kilometers) from Earth, that the details of what’s coming will be known. The satellite is like the ocean buoys that warn of a hurricane.
The trip from ACE to Earth will take the CME about 30 minutes, Gordon said.
When the CME hits, it’s time to “finish battening down the hatches,” Gordon said.
The other thing ACE does, as will the the National Oceanic and Atmospheric Administration’s new DSCOVR satellite in a month or so, is measure solar wind. Gordon said the wind, made up of protons and particle matter streaming out of the sun, was one indications to forecasters that Monday’s event was winding down.
The wind speeds dropped to 567 kilometers per second for a time on Tuesday from about 800 kps Monday. On a quiet day, the solar wind is between 300 to 350 kps.
“Like the wind speed on Earth, it’s a good barometer of how much activity there is,” Gordon said.
So sometime later Wednesday it will be time to put up that umbrella and get ready for a second round.
Here’s hoping it will be as uneventful as the first one.
(An earlier version of this story incorrectly converted miles to kilometers in the 14th paragraph.)