Biggest Breach of Earth's Magnetosphere

NASA | THEMIS Discovers Biggest Breach of Earth's Magnetosphere

NASA's THEMIS mission has overturned a longstanding belief about the interaction between solar particles and Earth's protective magnetic field. This new discovery could help scientists predict when the solar storms that can disrupt power grids, satellites and even GPS signals, could be especially severe.

"At first I didn't believe it," says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. "This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction."

"The opening was huge—four times wider than Earth itself," says Wenhui Li, a space physicist at the University of New Hampshire who has been analyzing the data. Li's colleague Jimmy Raeder, also of New Hampshire, says "10²⁷ particles per second were flowing into the magnetosphere—that's a 1 followed by 27 zeros. This kind of influx is an order of magnitude greater than what we thought was possible."

The years ahead could be especially lively. Raeder explains: "We're entering Solar Cycle 24. For reasons not fully understood, CMEs in even-numbered solar cycles (like 24) tend to hit Earth with a leading edge that is magnetized north. Such a CME should open a breach and load the magnetosphere with plasma just before the storm gets underway. It's the perfect sequence for a really big event."

Sibeck agrees. "This could result in stronger geomagnetic storms than we have seen in many years."

Read more Biggest Breach of Earth's Magnetosphere at NASA and Multiple rifts in Earth's magnetic shield at Science & Technology.