“Space Weather” Can No Longer Be Ignored
(An expanded version of a review of Storms from the Sun by Michael J. Carlowicz and Ramon E. Lopez , which first appeared in the May 2003
The most powerful solar X-ray flare
on record lit up the Sun on April 2,
2001, as seen through SOHO’s EIT
(Extreme Infrared Telescope). [SOHO
is a cooperative project between
NASA and ESA]
Now that we’re in space, “space weather” is in our face. As our society has become increasingly technology-dependent, as people work in orbit and our network of satellites continues to grow, it becomes ever more important to understand solar activity and how it affects the Earth and the space surrounding our planet. “Storms from the Sun: The Emerging Science of Space Weather,” by Michael J. Carlowicz and Ramon E. Lopez ($27.95, Joseph Henry Press), presents a thorough, lucid, enjoyable, and at times alarming account detailing human efforts to understand and forecast the effects of solar activity on Earth and its near-space environment.
The Sun is a variable star; we live within its atmosphere and are subject to its outbursts. When the solar wind, a stream of hot plasma (ionized gas) emanating from the Sun into space, encounters the Earth’s magnetic field, it can cause auroras in polar latitudes. More violent events such as flares and coronal mass ejections can hurl high-energy subatomic particles towards the Earth; they can cause intense geomagnetic storms that spawn auroras nearly down to the equator, disrupt power and communications and endanger satellites, astronauts, and even frequent air travelers.
Until the mid-1800s, the only known manifestation of “space weather” was the aurorae. The book describes human attempts to understand the sun from ancient times through Galileo’s observations of sunspots, Heinrich Schwabe’s discovery of the 11-year sunspot cycle and Maunder and Spoerer’s finding longer-term variations in solar activity, Carrington and Hodgson’s pioneering observations of a solar flare in 1859 (which disrupted not only magnetometers but also zapped the telegraph system of that day), and research on aurorae by several scientists, most prominently Kristian Birkeland, who created the basic model of the electromagnetic link between Earth and Sun. The account continues into the Space Age, and the discovery of the Van Allen radiation belts, the two doughnut-shaped regions that magnetically trap protons and electrons around the Earth.
Although the historical build-up is fascinating, Carlowicz (a science writer) and Lopez (a space-weather physicist) are at their best describing our modern world and the challenges and dangers space weather presents. The book starts by describing one of the most intense solar storms ever recorded, which lasted from April into June of 1998. On May 19 the Galaxy IV satellite failed, putting several broadcast networks--including CBS News and NPR— as well as 85 percent of North America’s pagers out of commission. Forty million people, everyone from doctors and real estate agents to drug pushers, lost their ability to page—the first major outage in 35 years. Several other satellites, including Germany’s Equator-S science satellite and four of the newly commissioned Iridium fleet, also failed around that time. Some solar physicists have attributed the loss of Galaxy IV to “dielectric charging”: a build-up of high-energy electrons, which can penetrate the spacecraft’s shell, on materials that insulate the satellite’s electronics. Should the flood of electrons be great enough, they can discharge, frying the electronics. Other satellites, such as the Canadian Anik, have been lost under similar circumstances. With huge amounts of money and the prestige of companies riding on the performance of satellites, understanding how they fail and how to best protect them from is vital.
Electromagnetic storms can also overload the terrestrial power grid. The authors describe how electric currents from a similar solar storm on March 13, 1989 caused overloads in power systems around the world, destroying a $10 million transformer in New Jersey and causing 6 million people in and near Quebec to lose power on a frigid night.
In early August, 1972, near the time of predicted solar minimum, the sun suddenly erupted in activity and sent X rays and high-energy protons in our direction. This fell between the Apollo 16 and 17 missions; should this storm have occurred as the astronauts were heading to the Moon, they would have been unable to avoid it nor to turn around. According to the best projections available at the time, the three astronauts would have suffered vomiting and other symptoms of radiation sickness. They would have needed to be hospitalized for up to 6 months, with a 20 percent chance they would have died from the accumulated radiation. A similar storm affected astronauts aboard Mir and the Space Shuttle Atlantis in 1989, but as the spacecraft were well within the Earth’s protective magnetosphere, they suffered no permanent harm.
The need to be able to understand and predict solar storms over the short term is clear, but it is just as important to understand the changes in activity over years and centuries. The 11-year sunspot cycle is proving more complex than originally thought, and there may be other periodic changes just coming to light. By studying changes in the Sun’s radiance over time, we can help determine what climatic changes are natural, and how much of an effect human activities are having on Earth’s climate.
Organizations like the National Oceanographic and Atmospheric Administration (NOAA) in Boulder, Colorado are actively involved in trying to forecast solar activity and its effects on Earth and its orbital environment. There are now a flotilla of satellites such as SOHO, Japan’s Yokkoh, NASA’s TRACE (Transition Region and Coronal Explorer), and ACE (Advanced Composition Explorer) compiling data to prepare us for the vagaries of the star that is so near to us but we are only now beginning to understand.
E-mail to tonyhoffman [at] earthlink [dot] net