If you missed the brilliant displays of the aurora borealis over North America on May 10, you may have another chance to see them on Friday night.
The same sunspot region that triggered Earth’s largest magnetic storm in almost 20 years earlier this month has rotated back onto the Earth-facing side of the sun, albeit, a little more subdued than the last time it came around.
The U.S. government’s National Oceanic and Atmospheric Administration (NOAA) rates geomagnetic storms from G1 (minor) to G5 (extreme), and while the storm on May 10 was designated G4, Friday’s is forecast to be a G2, or moderate, storm.
Nonetheless, night sky viewers might still be able to spot the lights over Canada and the northern Midwest United States.
A Kp index of 6 or higher has sometimes allowed for glimpses of the aurora in the Maritimes. (Source: CTV News Atlantic)
Auroras usually present as a milky green glow in the night sky and result when the sun emits a strong surge of solar wind from its corona called a coronal mass ejection (CME). This gust of solar plasma disturbs the outer part of the Earth’s magnetic field, causing a geomagnetic storm.
Strong geomagnetic storms can impact infrastructure in near-Earth orbit and on Earth’s surface, potentially disrupting communications, the electric power grid, navigation, and radio and satellite operations.
The sun emitted a strong solar flare on May 29. NASA’s Solar Dynamics Observatory captured an image of the event, which was classified as X1.4. (NASA)
This CME flared out from Active Region 3697 for about an hour on Wednesday morning, according to NASA, and is expected to reach Earth starting Friday afternoon, continuing through early Saturday morning.
For updates on the coming aurora, visit the NOAA website.
With files from CTVNews.ca National Affairs Writer Christl Dabu and CTV News Atlantic