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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.”
Quintet of Satellites Working on the Project
Five customized weather satellites, launched by NASA in February 2007, are now orbiting the Earth for THEMIS. They are helping researchers determine how the beautiful, dance-like movements of the aurora borealis can be indicators of storms on the edge of space that directly affect people’s lives.
The satellites are interconnected via private link to 20 specially equipped observatories in Alaska and Canada. Every four days, the quintet lines up along the equator to gather and record photographic and weather data showing where, when and how substorms develop.
The satellites are sophisticated relay stations that take photographic and videographic data from the 20 observatories and beam it back to mission control at the University of California, Berkeley, headquarters of THEMIS. As a failover or backup, the images also can be sent to the Goddard Center in Maryland.
“We discovered that whenever auroras are going on, that there are changes in the Earth’s magnetic field,” Sibeck said. “Instabilities happen, and they could go off at any time. We’d like to know what those instabilities are. We couldn’t do that in the past with only one spacecraft; it’s not enough to pin down when and where things are happening.”
The Canadian and Alaskan observatories are positioned so that they can photograph the entire sky every fourth night, taking photographs or video through fisheye lenses every 3 seconds and beaming the images to one of the satellites, which in turn sends the data to the Berkeley or Maryland data centers for processing and storage.
“We have eight satellites up there at the moment doing a total of four missions; five of the satellites are doing the aurora borealis work,” said Dr. Manfred Bester, director of THEMIS mission control in Berkeley. “A good amount of the video and still photographs that are taken are moved right onto our Web servers, so that the general public can see the northern lights in action.”
NASAs Open Data Policy
This is all part of NASA’s relatively new “open data” policy to share almost everything in the public domain, Bester said. This is a radical change from the Cold War years, in which any kind of scientific information was kept sacrosanct so that countries behind the so-called Iron Curtain couldn’t use it for their own advancement.
“In fact, the entire data set is available to read on the Web site,” Bester said. “It’s a big flood of data that we have to handle, so it’s rather complex. If somebody wants to analyze the data on their own, they are welcome to it.”
Bester said the THEMIS project just bought a set of new, dedicated Linux-based RAID storage arrays and data servers from Silicon Mechanics-several terabytes’ worth of raw storage-to handle the additional influx of satellite data from the five satellites. About 40GBs worth of film and photos is processed per evening, Angelopoulos said.
No custom-made software is being used for the data transfers, Bester said. It’s all being beamed over the Internet using standard industry software from SGI and other companies.
“We are using some specially developed tools to provide access to the data for the general community,” Bester said. “What you see on the Web site is sort of an overview of what the scientists see each day; it’s compiled a bit for the general public.”
The Berkeley operations center also is in the process of installing a new 20TB server from Sun Microsystems to store the THEMIS data.
“Our 10TB server nearly filled up with THEMIS science within about
18 months, averaging at about 130GB per week,” Bester told me. “Most of those data are from the all-sky imagers. The five spacecraft combined generate about 3GB per week. Data from the five spacecraft are downloaded through ground stations at a rate of about 1Mb/ps when they pass near Earth.”
The newest addition to the system is a SunFire X4500 Thumper 64-bit server running Solaris 10 OS on 2x AMD Opteron Model Dual-core 290 2.8 GHz Processors. It features 48 3.5-inch 1TB SATA hard drives.
Understanding Space Weather
Angelopoulos said the entire study of space weather is of increasing interest to governments all over the world.
“We are at the beginning of our understanding of space weather, much [as] 100 years ago we were at the beginning of our understanding of atmospheric weather,” Angelopoulos told me. “Just like back then, scientists were using weather stations to track storm fronts, today we need to be using fleets of satellites to track space weather fronts.
“THEMIS ushered [in] a new era of satellites, launched to track ‘weather fronts’ in space and [that] have already paid off by their discovery of what triggers substorms. This will pay great dividends in modeling space weather and in developing tools for accurate and timely space weather prediction.”
Editor’s note: This story was updated Aug. 2 to include more detail about the IT system at the Berkeley operations center.
Editor’s note (2): To access general information and the data set of the THEMIS Project, go here. To view still photos, go here.
To view video of the aurora borealis, follow these instructions: Start here. Select “All Sky Imager” under “Source.” Pick a date earlier this year and click display.
A pop-up appears, like this, if your computer is set to allow pop-ups. Click “Movie.” You will see the aurora displayed against the image of Canada.
