11
The Forecast
Mama always told me not to look into the sights of the Sun. . . .
Oh, but Mama, that’s where the fun is . . .
Bruce Springsteen, “Blinded by the Light”*
They sit in front of a bank of computers and monitors, perhaps a dozen glowing phosphorescent screens. They pore over mathematical wiggles and line plots, spacecraft images of the Sun and the aurora, and old-fashioned hand-drawn sketches of the solar surface like the ones Galileo and Carrington made centuries ago. From this fluorescent-lighted and white-walled room tucked into the center of a new office building, they cannot see the Sun, at least not the visible one warming Boulder, Colorado, on a summer day. “They” are the men and women who forecast space weather for the United States and much of the world. They
work for the Space Weather Operations Center—a joint operation of the National Oceanic and Atmospheric Administration’s (NOAA) Space Environment Center (SEC) and the U.S. Air Force—as the official monitors of solar activity and of conditions in the space around Earth.
Life as a space weather forecaster in the operations center is hardly glamorous. Unlike the dramatized control rooms of the Apollo missions to the Moon or of Hollywood science flicks, the day-to-day routine in the SEC forecast center seems almost monotonous and uneventful. And most days the forecasters probably prefer it that way. Excitement at the SEC means billions of dollars worth of equipment and commerce are being threatened by an environment we can barely see and are only beginning to understand.
On one morning in June 1999, Eric Ort was watching the Sun and its antics. A lieutenant in the NOAA uniformed corps of officers, Ort was the official forecaster for the day, charged with predicting what the Sun would do next. He scanned the images and radio data from telescopes at solar observatories in Australia, Puerto Rico, Massachusetts, Italy, and New Mexico. Picking a fax out of the machine, he reviewed the hand sketches of sunspots, coronal holes, filaments, and prominences of the Sun as drawn by observers at Holloman Air Force Base in New Mexico. Ort looked up at the many plots of data on the computer screens above and around him: measurements of solar X rays and high-energy particles bombarding the magnetosphere and magnetometer readings of changes in the Earth’s magnetic field. He glanced at e-mails and imagery on the World Wide Web from the science team of the Solar and Heliospheric Observatory (SOHO), which takes images of the Sun 24 hours a day. He scanned the real-time data from the Advanced Composition Explorer (ACE) satellite, which gives Ort in situ measurements of the speed, magnetic orientation, and density of the solar wind from a position about 1 million miles toward the Sun, in front of Earth.
Marshalling all of his data, plus a few years of experience and training, Ort devised a probability for what the solar activity would
be for the next three days and whether that activity would affect Earth. He followed certain algorithms and statistical formulas developed by the research scientists down the hall and made an educated guess about the future. On that day he predicted that the planetary K index (Kp)—a measure of the space weather storm activity around Earth, similar to the Saffir-Simpson scale of hurricane intensity—would be between 1 and 3 on a scale that goes to 9. “It should be a quiet day,” with minimal activity, Ort noted as he compiled his forecast, “though there is a coronal hole on the western limb of the Sun that could be geoeffective.”
Had this been March 1989 or May 1998, when the Sun was teeming with activity, the prediction would have been much more difficult and probably much less reliable. Ort might have had to issue an “alert” to say that a significant solar event had been observed, a “warning” that a space weather event near Earth was “highly probable,” or a “watch” asserting that conditions were favorable for a space weather event. But the Sun seemed to be behaving that day, so he thought he would have some time to catch up on his paperwork and his ongoing education in space science. Based on the outcome of his prediction—the Sun barely peeped for the two days after Ort’s prediction and the Kp index never rose above 2—it appeared that his education was coming along nicely.
Electric power companies, surveyors, satellite operators, the military, radio operators, some parts of NASA (such as the Space Radiation Analysis Group at the Johnson Space Flight Center)— even pigeon racers—all look to Ort and his fellow SEC forecasters to warn them of incoming storms from the Sun. The job of space weather forecaster is comparable to the work of the forecasters at NOAA’s National Weather Service, according to Ernie Hildner, director of the Space Environment Center. The forecasters must specify the current conditions (Is it raining protons? Is the solar wind blowing hard?), make predictions about possible changes in that environment, and issue warnings to the nation about the space weather equivalent of hurricanes, tornadoes, and blizzards. But unlike their colleagues tracking terrestrial weather—who have a reasonable understanding of how weather moves and changes af-
ter nearly two centuries of daily reports—SEC forecasters have to roll the dice daily because the science is still so new, the data are so sparse, and the tools of the trade are still being developed.
“In the beginning, in the 1960s, all we did was observe the Sun with one solar telescope, one riometer, and one magnetometer,” notes Gary Heckman, a 35-year veteran of the space weather center and the senior forecaster. “About a decade ago, we got the right day of a major storm about 25 to 40 percent of the time”—when they even knew that a storm was coming. “Now we are about 50 percent correct at predicting the big storms.” Most of the staff at SEC will readily admit that the science or art—depending on one’s perspective—of predicting space weather is about as mature as terrestrial weather prediction was in the 1960s.
“We need a better set of measurements, more observational tools, and better models” to really become more precise in the predictions, Heckman adds. Using a limited amount of data and a limited understanding of how the Sun generates storms, Heckman, Ort, and others must venture a prediction each day about what the Sun will do for the next three days and how turbulent the space around Earth will be as a result. They do this with timely information from just a handful of satellites and a few dozen ground-based observatories—there are more local weather stations in some states than the SEC has available for monitoring billions of cubic miles of space in three dimensions. They cannot see solar flares or coronal mass ejections from ground stations. And even with the spectacular views of the Sun provided by spacecraft such as the European Space Agency’s SOHO, Japan’s Yohkoh, and NASA’s Transition Region and Coronal Explorer (TRACE), the forecasters and scientists cannot say with much certainty when a solar storm will or won’t cross paths with Earth. They can only guess at the direction and trajectory of a storm until it actually washes over ACE, NASA’s spacecraft monitoring the solar wind from a position 1 million miles out in front of Earth.
According to Heckman, the introduction of real-time solar wind data from ACE has been the greatest recent improvement in space weather monitoring because it essentially provides a
“nowcast.” Sitting in a direct beeline from the Sun and bathing constantly in solar particles and radiation, the ACE can detect trouble just before it reaches Earth. This allows forecasters to give warnings about 30 to 60 minutes before a storm arrives. To date, SEC forecasters have been right as much as 80 percent of the time when a disturbance is detected by ACE, according to Heckman. “Once you get past one hour, however, the forecast becomes much less reliable.”
An hour of advanced warning about space storms is useful for the electric power companies because they can temporarily change the way they generate and move electricity. Depending on the time of day and the amount of electricity being consumed, companies can shed some of the load on the systems, increase their power-generating capacity, or defer maintenance on some power lines until the threat has diminished. For instance, in a July 2000 storm, the U.S. Nuclear Regulatory Commission advised nuclear power plants to operate at 80 percent of capacity so that they would have a margin of error if the magnetic storm produced strong geomagnetically induced currents.
But for the satellite operators it can cost too much money and time to adjust to every potential blip in the space environment. If operators are concerned about space weather events during a period when they need to issue a lot of commands, they will sometimes postpone those commands—even a rocket launch—until a storm passes. But rarely do spacecraft get shut down altogether due to a possible storm. Operators instead go into a heightened state of alert, preparing for recovery from a failure rather than trying to prevent one. Space weather failures may cost a lot of money, but so do false alarms when there are too many of them. “If you shut off the satellite, you lose the income stream that the satellite would otherwise be generating,” notes Ernie Hildner. “For any single storm, the probability of your satellite getting hit is so low that turning it off is just not the economical thing to do.” Right now, the SEC predictions are too variable too often for most satellite companies to spend money mitigating a problem that may never occur. It is a calculated gamble they have to take.
Since the flights of Explorer 1 and Sputnik in the late 1950s, the Sun-Earth system traditionally has been studied as a set of independent parts—the Sun, interplanetary space, the magnetosphere, the ionosphere, and Earth’s upper atmosphere. Over the past 40 years, space scientists have developed and refined instruments in support of dozens of individual satellite missions, including the Interplanetary Monitoring Platforms, the Solar Maximum Mission, the Dynamics Explorers, Helios, and the International Sun-Earth Explorers. But each of those programs, while greatly advancing one aspect of the science of solar-terrestrial physics, usually made their measurements in one region of space with one set of instruments and parameters that were not necessarily set up to match what was being studied by other spacecraft. Real-time coordination and correlation with other missions, scientists, and instruments occurred more often by happenstance than intention.
To better understand the Sun, the Earth, and the space in between as an integrated dynamic system, scientists eventually decided that they needed a program of simultaneous space- and ground-based observations coupled with theoretical studies. They had to find a way to assess the production, transfer, storage, and dissipation of energy from one region to the next, with most of that energy moving in ways that are invisible to traditional telescopes and cameras. Most of all, they needed to gather and store data in formats that any space scientist could use. In essence, they needed a comprehensive, quantitative study of the movement of energy from the surface of the Sun to the surface of the Earth. It took two decades of discussions, planning, coordination, and budget fights—particularly because no one nation could afford to pay for such a massive undertaking—but the scientific community came up with an answer: the International Solar-Terrestrial Physics (ISTP) program.
ISTP was conceived in the 1970s, planned in the 1980s, and launched in the 1990s. The mission was intended as a global effort
to observe and understand our star and its effects on our environment. An armada of more than 25 contributing satellites— working together with ground-based observatories, computer simulators, theoretical modeling centers, and data repositories— allowed scientists to study distinct but connected parts of the Sun-Earth system simultaneously from many perspectives and in many different ways.
The primary missions of ISTP—Geotail, Wind, the Solar and Heliospheric Observatory, Polar, and Cluster II—allowed physicists to observe all the key regions of Earth’s neighborhood in space. The first satellite, Geotail, was launched in 1992 by Japan’s Institute of Space and Astronautical Science (ISAS) to study the distant reaches of Earth’s magnetic tail, the region downwind on the nightside of Earth. In 1994, NASA launched the Wind mission into an orbit that sent it on long loops toward the Sun and around the Moon, allowing the satellite to sample the solar wind from outside the magnetosphere. Late in 1995, the European Space Agency (ESA) and NASA launched SOHO to observe the Sun in several wavelengths, full-time, from space—without the intrusion of Earth’s shadow—and to conduct studies of activity inside the Sun. In 1996, NASA added the Polar satellite to swing over Earth’s North and South Poles in order to monitor the aurora and the flow of currents and plasmas into and around the magnetosphere. Finally, in the summer of 2000, ESA launched the quartet of identical spacecraft known as Cluster II, four years after the original four spacecraft blew up during a failed rocket launch in June 1996. Satellites nicknamed Tango, Salsa, Rumba, and Samba now fly in a lopsided pyramid (or tetrahedron) formation, skimming the flanks of the magnetosphere in order to make simultaneous multipoint measurements and to create a three-dimensional picture of space weather activity.
In addition to these flagships, ISTP received significant contributions from other spacecraft, theory centers, and ground-based facilities run by Russia’s Space Research Institute, NOAA-SEC, Los Alamos National Laboratory, Germany’s Max Planck Institute, the U.S. Air Force, the Canadian Space Agency, the British
Antarctic Survey, and the National Science Foundation. In all, nearly a thousand scientists from more than 30 countries contributed observations to and analyzed data from the mission.
“ISTP has been one of the first programs to integrate experimental observations and theoretical physics successfully,” notes Mario Acuña, project scientist for the ISTP program, based at NASA’s Goddard Space Flight Center. “All of the ISTP elements were integrated into the ground system, which made the whole enchilada work as advertised. And we have proven to the world that theory is necessary to understand and extend observations where no spacecraft will ever go.”
Dan Baker, one of the most vocal advocates of the coordinated studies of ISTP, notes how scientists can now study solar-terrestrial physics in microcosm and macrocosm. “Individually, the spacecraft contributing to ISTP act as microscopes, studying the fine detail of the Sun, the solar wind, and the boundaries and internal workings of Earth’s magnetic shell,” says Baker, head of the Laboratory for Atmospheric and Space Physics at the University of Colorado. “When linked with each other and the resources on the ground, they act as a wide-field telescope that sees the entire Sun-Earth environment.”
The first real test of the ISTP philosophy came in January 1997, when the program’s science team gathered at NASA’s Goddard Space Flight Center in Maryland for a workshop. Assembled from laboratories around the world, the ISTP team was meeting to share past observations of coronal mass ejections (CMEs), flares, and bursts of high-speed solar wind and to coordinate future ones. It was a purposeful attempt to start evolving the field from uncoordinated, single-point studies of the space around the Earth to a global, system-wide perspective on how the Sun and Earth work together. But those few hundred scientists were not necessarily planning to do science in real time. During one of the science presentation sessions, solar physicist Don Michels of the U.S. Naval Research Laboratory walked to the front of the room and displayed images from earlier that day. He showed a time sequence where a cloud of plasma was bursting out from the Sun and head-
ing toward Earth. While it did not appear to be an extraordinary CME, it was the first time the whole science team would watch such a storm develop in real time as it moved from Sun to Earth. Not only were they going to observe a space weather event in concert, they were going to do it in the same room.
When the CME arrived at Earth on January 10, the magnetic cloud of solar plasma took most of a day to pass. NASA scientist Keith Ogilvie estimated that the cloud was perhaps 30 million miles across, about the distance from Earth to Venus. And as his NASA colleague Robert Hoffman noted, the cloud “packed a one-two punch.” Initially, the CME poured energy into the magnetosphere, initiating a magnetic storm and pumping up the energy in the radiation belts. Then, early on January 11, an unusually dense region of the CME cloud smacked the magnetosphere with a huge pressure pulse, with as many as 200 times more energetic particles packed into each cubic inch than in the rest of the cloud. “It was like Earth’s magnetosphere was hit with a hammer,” Hoffman said. “It rang the magnetosphere of Earth like a bell.” It also appeared to shake up AT&T’s Telstar 401 satellite, which suffered a catastrophic failure on January 11 (see Chapter 8).
The January 1997 storm made a big impression on the public as well as the scientific community. The loss of Telstar 401 and the fact that scientists had observed the event “from cradle to grave” made the event newsworthy. There were front-page stories in The Washington Post, The Times of London, and The New York Times, as well as broadcast reports on CNN, CBS, and National Public Radio. The media and the public were fascinated by the idea that the Sun may have killed a satellite. Just three months later, in April 1997, another CME was detected on its way toward Earth. Aided by some eager scientists still buzzing from the January storm, the news media announced that stormy times in space were imminent. This time there was some measure of panic in the public response. Nervous Californians called NASA to ask if the CME would trigger earthquakes. Rumors started to circulate on the Internet that the CME was actually a weapon that had been fired at the Earth by a UFO trailing comet Hale-Bopp. The
eventual physical effects of the storm were minimal—auroras were visible in Boston and other northern U.S. cities, but no satellites or power grids had major failures. And, of course, no UFO emerged from behind the comet. But the April 1997 CME did have a practical effect. The UFO and earthquake incidents reminded scientists that there was a need for greater public understanding of the issue and the actual hazards associated with space weather. It also reminded those scientists that storms from the Sun are still difficult to predict.
The January 1997 event was proof of the ISTP concept. Images and observations from solar telescopes had been coupled with solar wind measurements; the information about the solar wind was compared with the effects measured in Earth’s auroral zones, radiation belts, and magnetic tail. ISTP investigators had made the first complete, real-time study of a space weather event at a pace that Richard Carrington and Elias Loomis could have only dreamed about when they observed the great flare and aurora of 1859. And in a modern, Internet-wired world, they were able to share their observations and predictions—with colleagues around the world and with the taxpaying public—as the events were happening in real time.
“The international nature of the mission is a big plus and a big part of the experience,” adds Pål Brekke, the European Space Agency’s deputy project scientist for SOHO. The coordination of financial resources has allowed the spacecraft designers to think bigger; the coordination of scientific minds has allowed scientists to think more broadly. “A whole generation of American and European physicists are getting to know one another much better than they once would have only through meetings. It’s a binding experience to work on a labor-intensive mission together.”
As a result of a decade of cooperation and collaboration among scientists and nations, the paradigm of one-spacecraft/one-region studies has given way to global views of solar-terrestrial science. Some of NASA’s newest Sun-Earth spacecraft—such as ACE, TRACE, the Fast Auroral Snapshot Explorer (FAST), and the Imager for Magnetopause to Aurora Global Exploration (IMAGE)—
are not formal members of ISTP, but each mission is collaborating with the existing ISTP missions because the scientific community now demands coordinated science.
In 2001 two new missions were launched and two others were being readied to both widen and focus that global view. On July 23, NOAA launched a new Solar X-ray Imager (SXI) as an instrument on the agency’s newest GOES weather satellite, allowing solar physicists to collect minute-by-minute images of the Sun in X rays. Two weeks later the Jet Propulsion Laboratory and NASA launched the Genesis mission to capture samples of solar wind and stardust for three years before returning them to Earth. The Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission of the Johns Hopkins University Applied Physics Laboratory and NASA was launched in December 2001 to study the uppermost reaches of Earth’s atmosphere, where space weather phenomena may be coupled to the processes that drive our weather and climate. And finally, the High-Energy Solar Spectroscopic Imager (HESSI) was launched by NASA in February 2002 on a mission to explore the basic physics of particle acceleration and energy release in solar flares.
“Never before have scientists had such a complete set of tools with which to study the climax of a solar cycle,” notes Dan Baker. “And never before have they had tools of such power and precision to study our most important star—the Sun—and our most important planet—Earth.” By using these coordinated measurements— in the manner of atmospheric scientists who study global change through thousands of weather stations—space scientists are now dreaming about a day when they can make “weather maps” of approaching storms from the Sun. They are also vastly improving the models of space weather disturbances from solar outburst to impact on Earth’s atmosphere.
The laws that govern electricity and magnetism are deceptively simple. There are only four of them, and they are named the
“Maxwell Equations” after the great nineteenth-century physicist James Clerk Maxwell. When Maxwell’s work is combined with the equations of fluid flow for an electrically conducting gas, one arrives at the equations of MagnetoHydroDynamics, or MHD. In the minds of some scientists, MHD stands for “My Horrible Dream” because the resulting equations are so complex that they can be solved for only a very small number of special situations. Yet they are the equations that must be solved with ever more precision if scientists are going to understand and then predict the movement of energy and plasma from Sun to Earth.
Enter the computer. Any system of equations can be “solved” numerically by crunching the numbers to calculate the implications of the equations for a particular situation—that is, to create a simulation. The key is to have enough computing power to solve the equations within the desired time- and spatial scales. For years, MHD simulations of the magnetosphere were rather crude, idealized, and not practical or useful for advancing space weather prediction because few people had the time or the heavy-duty computers to handle all of the variables and permutations. In the mid-1990s that began to change. Computing power had advanced to the point where lots of realistic physics (though not all) could be built into the models. Models could suddenly be run in “real time” so that it would take a supercomputer one hour to simulate one hour of time. So various groups began to experiment with using real solar wind observations from spacecraft like Wind and ACE to drive their models, instead of invented solar wind conditions that are computationally easy to handle.
Such models have changed the way physicists see the invisible realm of the magnetosphere. “We have created the first global pictures of what is going on in the magnetosphere,” notes Charles Goodrich of the University of Maryland, who has developed visuals of one of those models. Using a Cray C-90 and other powerful computers, Goodrich and colleagues (including one of the authors of this book) developed a series of scientific visualizations and a detailed analysis of the simulation results that depict for the first time how the magnetosphere responds to the shock of a real CME.
“Since we only have a few spacecraft, and they can only make point measurements,” Goodrich adds, “this is the only way to look at the whole system.”
As these new, more sophisticated simulations came onto the scene, scientists began comparing the results to real events. What they found was that the simulations work quite well at a global level. This is true even though the latest simulations still do not contain all of the physical processes that many space physicists consider important. Why do the simulations replicate reality as well as they do? The best answer could be that the solar wind is the key driver to magnetospheric activity, in contrast to terrestrial weather that is not so heavily forced on short timescales by solar activity. This also would explain why models of the magnetosphere based on chaos theory (which do not need to contain any plasma physics at all) reproduce a lot of the behavior of the magnetosphere using the solar wind input as a driver for the model.
This new understanding of the overwhelming role of the solar wind as a driver of the system, along with advances in our understanding of the basic physics of magnetic reconnection (the Cheshire cat of energy release in space plasmas), has led scientists to a grand idea. Shouldn’t we simulate the entire system, from the surface of the Sun to the upper atmosphere of the Earth? Scientists are working on this challenge, trying to link together the flow of energy and plasma from one part of the system to the next. It will take a decade at least to accomplish the goal, but initial results have been quite promising, mainly because scientists now have coordinated coherent data from each part of the system.
“Most of the models already in use today do a reasonable job of predicting average conditions, but few of them take into account the dynamics and how quickly the system can change,” says Terry Onsager, a researcher at the Space Environment Center who works to turn basic research findings into tools that forecasters can use. “But with the new stream of real-time measurements, we are beginning to synthesize mature models in order to give industry and the government the information it needs to work in space. Some of the new models that we are developing will allow us to visualize
the radiation environment over vast regions of space and then specify and predict the conditions at any location. And they can take away some of the subjectivity of forecasting.”
By the middle of the year 2000, the maturity and immaturity of the field of space weather prediction were on full display. Starting on July 11, 2000, forecasters at the Space Environment Center and scientists at ISTP mission control at NASA Goddard began closely watching solar active region 9077, a large group of sunspots with a complicated, gnarled structure. For four days they tracked a series of large flares and coronal mass ejections erupting from the region as it slowly lined up in the center of the solar disk for a head-on shot at Earth. Then, at 1024 Universal Time (6:24 a.m. U.S. Eastern Daylight Time) on July 14 (Bastille Day), the Sun unleashed a monstrous, long-lasting solar flare and with it a potent swarm of solar particles. A full “halo” coronal mass ejection was shot out from the Sun almost simultaneously, escaping the Sun at nearly 1,800 kilometers per second (4 million miles per hour).
The X rays and other light from the blast reached the cameras on SOHO and the flare sensors on the GOES weather satellites about 8 minutes later. Within 15 minutes after the flare, a stream of solar particles began bombarding the Earth’s magnetosphere (moving at half the speed of light). Just 36 minutes after the flare, the ACE spacecraft was bombarded with so many particles that it lost its ability to track solar wind density and velocity. Spacecraft cameras trained on the Sun—from SOHO, TRACE, and Yohkoh— and on the auroral zones of Earth—from Polar and IMAGE—were blinded by the swarm of solar particles. One of the radio transmitters on the Wind spacecraft permanently lost about a quarter of its power, forcing controllers to switch to a backup system. After detecting the initial blast from the Sun, the very satellites that were supposed to monitor the incoming space weather were temporarily blinded by it.
About 26 hours after the Bastille Day flare, three shock waves arrived at Earth (they arrived twice as fast as the typical CME cloud). The shocks and the trailing blob of CME plasma smacked into the Earth’s magnetosphere and compressed inside the geosynchronous orbit of many satellites. Because of the speed of the CME, forecasters had just 21 minutes between the detection of the storm by plasma and magnetic field detectors on the ACE spacecraft and the arrival at Earth; forecasters usually have 45 minutes to an hour of warning. By late afternoon on July 15, the largest magnetic storm since March 1989 began distorting the atmosphere around Earth, with a storm that reached the top of the scale on the index of space weather intensity (a 9 on the Kp scale of 1 to 9). Auroras raged in the skies over Europe, though few observers in the Americas saw the event at its peak because it occurred at 8 p.m. Eastern Time while the summer Sun was still marching toward the horizon. Had the storm occurred just a few hours later, observers would have seen auroras as far south as Florida and the Gulf of Mexico (see Figure 17).
Because space weather forecasters saw the storm brewing days ahead of time and issued alerts and warnings to let industry and the public prepare for the onslaught, damage from the Bastille Day storm of 2000 was mitigated. Electric currents caused by the magnetic storm caused voltage swings, tripping of capacitor banks, and damage to power transformers at more than a dozen electric power plants and companies in North America, but there were no blackouts. Had astronauts been working on the space station or the shuttle, they would likely have received the equivalent of a year’s worth of allowable radiation in a matter of days. But no one was living on Mir or Alpha, and the shuttle was parked in Florida. Numerous commercial, military, and civilian science satellites suffered some damage to their solar panels or errors in their computer systems, but most equipment survived with some help from operators on the ground.
But the operators of Japan’s Advanced Satellite for Cosmology and Astrophysics (ASCA) were not so fortunate. While the satellite did not suffer any major failures from the swarm of energetic
FIGURE 17. The Visible Imaging System on NASA’s Polar spacecraft captured this image of the auroral oval at the peak of the July 2000 magnetic storm, around 8 p.m. U.S. Eastern Time on July 16. Auroras would have been visible across the entire continental United States had the storm occurred after dark. Courtesy of Visible Imaging System/University of Iowa and NASA.
particles, it was destroyed in a backhanded way. The energy from the flare and the CME increased the density of Earth’s upper atmosphere so much that atmospheric drag began to pull the satellite down. The friction was so intense that it overwhelmed the momentum wheels that should have helped ASCA orient itself in space. Instead, the satellite went into a spin and lost power because its solar panels were no longer pointed toward the Sun. An astronomy satellite that studied black holes and distant galaxies was wiped out by the one star that it did not watch.
“This is a unique solar maximum, the most exciting in history,” asserts George Withbroe, science director for NASA’s Sun-Earth Connection program. “We have the most powerful fleet of spacecraft ever launched to study the Sun and its effects on Earth.” Where once space scientists could only view the Sun for limited portions of the day from Earth or from orbits that descended into the planet’s shadow several times a day, for the past five years they have been able to watch the Sun constantly. In a field where magnetic storms were typically detected after magnetometers on the ground started twitching, scientists have been able in recent years to use radars and spacecraft to pick up the signatures of those storms before they churn up the atmosphere. “The images and data are beyond the wildest expectations of the astronomers of a generation ago,” Withbroe adds. And with the development of the Internet and the foresight of an open-data policy whereby all of the science teams share the observations from their instruments, just about all of the images and data are available for the world to see on the World Wide Web.
The ISTP era and the advent of 24-hour-a-day images of the Sun from SOHO have energized the field of solar-terrestrial science and provided scientists with a host of new discoveries and direct confirmations of long-held theories. In the past five years, space scientists have learned that the Sun squeezes a little bit of Earth’s atmosphere into space with every CME blast. They have found that the atmosphere of the Sun occasionally configures itself in peculiar “S-shaped” structures before it launches some of its CMEs. Using sound waves from inside the Sun and beams of ultraviolet light propagating through the solar wind, researchers have begun to create images and models of the far side of the Sun, providing hope of space weather predictions made weeks in advance, rather than days. Combining auroral imagery with particle and magnetic field measurements in the cusps and tail of Earth’s magnetosphere, space physicists have been able to gather firsthand evidence that magnetic reconnection is not just a blackboard theory and laboratory curiosity but an actual mechanism for moving energy in and around the Sun-Earth system. Using radio bursts
and solar wind models, researchers are starting to make better predictions of the arrival of CMEs at Earth, narrowing the best estimates from a matter of days to hours. They have even been able to create coarse images of the invisible plasma hovering and swirling in the space around the Earth in the radiation belts.
“During the last solar max, we did not have the tools to follow solar activity in all layers of the solar atmosphere,” says Pål Brekke of SOHO. “We now have all the data online via [the] Internet, so it’s very easy to keep an eye on not only the Sun but also the effects on the Earth’s environment.”
The challenge of the next decade will be to turn those research findings into useful models and tools that can help the forecasters at SEC. “Within the research community, there has been continuous progress in studying and modeling the space environment,” says Terry Onsager. “But very little of that research has made it into the space weather operations community. It’s not so much that we are behind the times. It’s just that clean, proven operations methods to handle all the new data are not available. Our job is to take the pulse of the research community and see where the real advances are made. Then we have to decide what we can move into operations.”
In other words, not every discovery or advance in understanding necessarily translates into a tool that can be used, reliably and cost effectively, in day-to-day space weather forecasting. The single biggest problem is that most of the discoveries of the past decade have been made with scientific research satellites that were designed for discovery and exploration, not for steady, daily monitoring of conditions. Every time researchers discover the “next big advance” in space weather forecasting, they are usually just offering a proof that a certain type of observation with a certain satellite in a certain situation can work. They make a discovery, suggest that it might be useful, and then move on to the next research interest.
By the very nature of the way science is funded, scientific advances and novel concepts that could turn into forecasting tools are often filed away in the data bins before they can be turned into reliable, reproducible applications for SEC. It is a troublesome
quirk of federal science programs that the government will pay billions of dollars for “basic” research projects in space sciences, but the practical applications are often left for industry, which doesn’t always answer the call. It certainly isn’t in the financial interests of a satellite company to spend its money to monitor the space environment and share that information for free with competitors. And government research programs rarely promote or financially reward scientists for the application of basic research, at least not in ways that draw many scientific minds to work on the “applied” side. For the scientific researchers trying to maintain a lab, a staff, and a standard of living, it is more compelling and self-preserving to propose “new” science exploration to the government budget managers than to admit that the old questions still need answers, that the old data and observations have not yet ripened into beneficial applications. NASA and the National Science Foundation, by their very charters, are not supposed to get involved with “monitoring” projects. So monitoring the weather—on Earth and in space—becomes a dirty word, an activity that is shunned because no one wants to be underfunded or taken for granted.
So as a practical matter, space weather forecasting is currently tied to the uncertain life of research satellites and instruments that may be gone before they can be fully integrated into forecasting schemes. For instance, while the SOHO and ACE missions have revolutionized the world’s view of the Sun and solar wind, the SEC forecasting team must be prepared to live without those tools. Why? Research missions are funded for limited periods of time. Once the major research objective is reached, the agencies are looking to the next big advance in science. Missions that SEC counts on—but cannot control or afford—are subject to frequent budget reviews and constant threats of cancellation so that the research agencies can tread on the cutting edge. But forecasting does not require constant advances in technology; it requires tried and tested and reliable observations and models. Until NOAA-SEC knows it can fly a spacecraft that will make the same measurements as SOHO, the staff will have to prepare itself for life without one of their most useful tools.1
Despite the tensions of basic research versus applied science, despite the growing pains of turning discoveries in individual regions of space into a new understanding of the Sun and Earth as a system, researchers remain transfixed by their star. Every new answer about how the Sun or magnetosphere works leads scientists to a new set of questions. It is like peeling the proverbial onion: peeling any layer away reveals another one just as complex and compelling. “Simply watching the never-ending procession of changes on the Sun in full-resolution movies still takes my breath away, even after five years of it,” says Joe Gurman, NASA’s project scientist for the SOHO mission. “Every time we image the Sun on any new timescale, we discover that things change on those timescales and on all longer ones that we can visualize.”
