spaceSpace and Physics

NASA Spacecraft Have Witnessed Mini Magnetic Explosions Taking Place Near Earth


Jonathan O'Callaghan

Senior Staff Writer

Artist's impression of the MMS spacecraft. NASA/GSFC

Scientists have managed to observe magnetic “explosions” near Earth using a fleet of spacecraft that are currently in orbit around our planet.

Published in the journal Science, a team from the University of New Hampshire (UNH) described how NASA’s four spacecraft in the Magnetospheric Multiscale (MMS) mission flew through a magnetic reconnection event for a few seconds on multiple occasions, providing tantalizing data back on Earth.


"This was a remarkable event," said Roy Torbert from the UNH in a statement. "We have long known that it occurs in two types of regimes: asymmetric and symmetric but this is the first time we have seen a symmetric process."

Magnetic reconnection is the process whereby magnetic field lines essentially “snap” together. In Earth orbit, this occurs when the solar wind interacts with Earth’s magnetic field lines. The event releases a huge amount of energy, and is thought to be the driver of space weather processes like our aurorae.

The MMS satellites launched in 2015 on a mission to learn more about how magnetic reconnection works. In the first half of the mission, they studied reconnection on the sunward side of Earth, where the process occurs asymmetrically and electrons are pushed away at supersonic speeds.

Now the first symmetrical event has been spotted. On July 11, 2017, the spacecraft flew through a region of Earth’s magnetotail where its magnetic field lines snapped together, pushing out electrons at 20,000 kilometers (12,000 miles) per hour, noted Gizmodo.

Magnetic reconnection in action. Michael Hesse/NASA Goddard/Joy Ng

It’s thought that the events on the sunward side dump energy into Earth’s magnetosphere, whereas those on the night side dump energy into our atmosphere, which is how they drive aurorae. This can also affect satellites in orbit and grid systems on the planet.

Other events are thought to be driven by reconnection too, such as solar flares on the Sun. "This is important because the more we know and understand about these reconnections... the more we can prepare for extreme events that are possible from reconnections around the Earth or anywhere in the universe," Torbert added in the statement.

And the latest data proves that, while these events are small, they are powerful enough to send particles streaming into our atmosphere. So next time you see an aurora, just remember it was probably sparked by a weird magnetic event in Earth’s magnetotail.


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