NASA has brought together a space weather satellite network, global communications and plenty of IT muscle to gain new insight into what causes the undulating streams of color known as the northern lights.
While the project is paying dividends in terms of pure scientific research, it will also have practical value here on Earth by potentially giving scientists a way to predict solar storms that trigger the eerily beautiful phenomenon.
NASA's THEMIS project (Time History of Events and Macroscale Interactions During Substorms) is dedicated to studying the high atmosphere. NASA scientists revealed July 24 in an article in Science Magazine that they now know why the northern lights dance the way they do.
The lights, also called the aurora borealis, are caused by immensely powerful bursts of charged particles from the sun's surface, which can also damage satellites in space while overloading and possibly shutting down electric power grids on Earth.
Damage to satellites in turn could affect telephone communications, degrade the ability of television networks to transmit signals to local stations or homes and knock out the GPS systems people use to find their way in unfamiliar territory.
Based on the recent data they have gathered, THEMIS researchers said, they believe that during aurora borealis events, "stressed" lines in the Earth's magnetic fields suddenly snap to a new shape, like a stretched rubber band that was suddenly released, in a process called magnetic reconnection. Researchers are still trying to find out why this happens and why it affects radio waves; that's the main thrust of the ongoing project.
THEMIS is counting on this new information to help them improve substorm models and forecasts, so that governments and companies can be forewarned about possible interruptions.
"Aurora are the visual representation of disturbances [substorms] in the atmosphere," David Sibeck, THEMIS project scientist at NASA's Goddard Space Flight Center, told me. "As they capture and store energy from the solar wind, the Earth's magnetic field lines stretch far out into space.
"Magnetic reconnection releases the energy stored within these stretched magnetic field lines, flinging charged particles back toward the Earth's atmosphere. They create halos of shimmering aurora circling the northern and southern poles."
Auroras are certainly beautiful to see, but more important is this: These changes in the ionosphere can have a profound effect, especially when it comes to the satellite communications we all depend upon. Disruption of HF radio communications, obviously, can be a serious problem for airline pilots all over the world.
Has a connection between the aurora and communications disruptions been proven? If so, how does it affect the radio waves?
"At times of large storms, auroras can be seen as far south as Florida, and within them there are many substorms," THEMIS project supervisor Vassilis Angelopoulos, a faculty member at UCLA, told me. "These are known to affect communications and to affect transmission of shortwave radio as well as GPS lock quality, because the ionosphere that reflects or transmits those waves is altered severely by the space particle radiation."