spaceSpace and Physics

A Crack Opened In Earth’s Magnetic Field And Stayed Open For 14 Hours

What did it let in or out?


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor

A great sweeping green aurora in the sky across an icy landscape
The closer to the Poles the better the auroras. Image credit: John a Davis/

On Thursday, a crack opened in Earth’s magnetic field and stayed open for nearly 14 hours, allowing Vecna and his minions through from the Upside Down. OK, perhaps not that last bit, but it did allow some powerful solar winds to pour through the hole, creating a geomagnetic storm that sparked some pretty epic aurora.

The crack in the magnet field was created by a rare phenomenon called a co-rotating interaction region (CIR) from the Sun. CIRs are large-scale plasma structures generated in the low and mid-latitude regions of the heliosphere – the region surrounding the Sun that includes the solar magnetic field and the solar winds – when fast and slow-moving streams of solar wind interact.


Like coronal mass ejections (CMEs), CIRs get flung out from the Sun towards Earth and can contain shockwaves and compressed magnetic fields that cause stormy space weather, which usually presents itself to us as pretty aurorae. 

This one hit Earth’s magnetic field in the early hours of July 7 and caused a long-lasting G1-class geomagnetic storm. National Oceanic and Atmospheric Administration (NOAA) analysts suspect a CME was embedded in the solar wind ahead of the CIR, reports. 

Don't worry, cracks in Earth's magnetic field are normal. The magnetic field acts as a shield to protect us from solar storms spat out by the Sun. It was thought they opened and closed relatively quickly but now we know they can stay open for hours.

"We've discovered that our magnetic shield is drafty, like a house with a window stuck open during a storm," said Harald Frey, lead author of a study on this discovery back in 2003.


"The house deflects most of the storm, but the couch is ruined. Similarly, our magnetic shield takes the brunt of space storms, but some energy slips through its cracks, sometimes enough to cause problems with satellites, radio communication, and power systems."

There doesn't seem to have been any radio blackouts or power outages this time but we have been treated to some gorgeous northern lights across Canada and the US.

The Sun is gearing up towards its most active period in the solar cycle (July 2025) and is already unusually active quite early. Your chances of spotting aurora are already pretty good right now but they're just going to get better and better over the next three years.  


spaceSpace and Physics
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