Scientists have found two large leaks in Earth’s magnetosphere, the region around our planet that shields us from severe solar storms.
The leaks are defying many of scientists’ previous ideas on how the interaction between Earth’s magnetosphere and solar wind occurs: The leaks are in an unexpected location, let in solar particles in faster than expected and the whole interaction works in a manner that is completely the opposite of what scientists had thought.
The findings have implications for how solar storms affect the our planet. Serious storms, which involved charged particles spewing from the sun, can disable satellites and even disrupt power grids on Earth.
The bottom line: When the next peak of solar activity comes, in about 4 years, electrical systems on Earth and satellites in space may be more vulnerable.
How it works
Earth’s magnetic field carves out a cavity in the sun’s onrushing field. The Earth’s magnetosphere is thus “buffeted like a wind sock in gale force winds, fluttering back and forth in the” solar wind, Sibeck explained.
Both the sun’s magnetic field and the Earth’s magnetic field can be oriented northward or southward (Earth’s magnetic field is often described as a giant bar magnet in space).
The sun’s magnetic field shifts its orientation frequently, sometimes becoming aligned with the Earth, sometime becoming anti-aligned.
Scientists had thought that more solar particles entered Earth’s magnetosphere when the sun’s field was oriented southward (anti-aligned to the Earth’s), but the opposite turned out to be the case, the new research shows.
The work was sponsored by NASA and the National Science Foundation and based on observations by NASA’s THEMIS (Time History of Events and Macroscale Interactions during Substorms) satellite.
How many and where
Essentially, the Earth’s magnetic shield is at its strongest when scientists had thought it would be at its weakest.
When the fields aren’t aligned, “the shield is up and very few particles come in,” said physicist Jimmy Raeder of the University of New Hampshire in Durham.
Conversely, when the fields are aligned, it creates “a huge breach, and there’s lots and lots of particles coming in,” Raeder added, at the news conference.
As it orbited Earth, THEMIS’s five spacecraft were able to estimate the thickness of the band of solar particles coming when the fields were aligned