Washington: The NASA scientists have discovered how dense particles near earth can send a plume up through space to help protect against incoming solar particles during certain space weather events.
In certain circumstances, a pool of dense particles normally circling earth, deep inside the magnetosphere, can extend a long arm out to meet - and help block - incoming solar material, a new study shows.
The magnetic field of the earth is surrounded in a region called the magnetosphere.
"It is like what you might do if a monster tried to break into your house. You would stack furniture up against the front door, and that is close to what the earth is doing here," said Brian Walsh, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The material that is usually much nearer earth stacks up against the outer boundary of the magnetosphere, throttling the interaction there and stopping solar material from entering.
Walsh and colleagues compared observations from the ground and in space during a solar storm Jan 17 this year.
This was a fairly moderate solar storm caused by a coronal mass ejection (CME) impacting the Earth's magnetosphere for several hours.
NASA's three THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft were in the right place at the right time - flying through the magnetosphere's boundary approximately 45 minutes apart - and caught this interaction.