Our Raging Sun
Practically from the day technology advanced into the Electric Age, the sun has shaken our belief in our understanding of its inner workings. As we continue to advance and explore beyond the bounds of our atmosphere, the hazards we face because of the sun increase as well. Thought to be a benign source of light and life for thousands of years, the sun is proving to be more than a quiet ball of radiant energy in the sky. The sun is a raging giant at our door.
In late August 1859, Richard Carrington recorded exceptionally large spots in the northern hemisphere of the sun. On 31 August, he noted a very large sunspot at about 45N solar latitude. Over the next several days, large auroral displays were seen widely all over the Northern Hemisphere and strange effects began to show up in telegraph systems from Scandinavia to Tuscany and from California to Washington DC. While the aurora blazed in the sky, static, disruptions and false signals caused by electrical currents disrupted message traffic in many places, but in one bizarre case, the telegraph line between Boston and Portland, Maine operated for roughly two hours without batteries.
In March 1940, a power outage occurred in Quebec, Canada during a large magnetic storm. Ten massive transformers were knocked off-line and a cascade of successive failures brought on power losses in Canada and in the northeastern US as well. At the same time, telephone and radio communications were disturbed, with fading and crackling at least. In some cases, systems failed entirely but in others, they worked far beyond normal capacity. Some radios, for instance, picked up stations hundreds of miles outside of their normal ranges.
In August 1972, a major communication cable that connected Chicago to the west coast was disrupted for nearly an hour when a magnetic storm interfered with Illinois and Iowa power stations. In April 1981, the Canadian power supply network broke down and in March 1989, the entire province of Quebec endured a nine-hour power outage when a major transformer blew out during one of the biggest geomagnetic storms of the decade.
Geomagnetic storms in the late 1970s prematurely downed Skylab, the first US space station. The surging solar wind created by a massive solar flare superheated the Earthís upper atmosphere and made it expand significantly. This increased the drag on Skylab, already in a too-low orbit. The space shuttle was not ready in time to make a planned adjustment to Skylabís orbit so the space station broke up and crashed to earth.
Quite a bit of near-Earth orbit space debris came down at the same time and several satellites had to get their orbits adjusted to keep them flying. The April 1981 event forced the Columbia space shuttle astronauts to fire engines to correct the shuttle orbit because of a similar atmospheric expansion. Had they been out on a spacewalk when the solar eruption began, they could have been in much more serious trouble because of radiation, but a mechanical problem delayed launch by two crucial days.
In January 1994, an uninsured Canadian communications satellite worth $225 million was lost to a solar storm. It, along with several other satellites, suffered malfunctions when energetic electron saturated the skin of the satellite until a charge built up and caused an electrical arc. The Canadian satellite attitude control failed and the whole thing spun out of control and disappeared into space. A solar storm in 1991 damaged the solar power arrays on orbiting geostationary satellites and considerably shortened their working lives.
What a mess! So whatís going on out there that would create such mayhem here on Earth? Nothing that hasnít been happening since the instant the sun fired up and became a thermonuclear furnace. It is all about coronal mass ejections, sunspots and solar flares, the makings of solar storms. The storms on the sun stir up the geomagnetic storms that create such havoc on Earth.
The varying solar activity has long been implicated in climatic variations. Periods of low sunspot activity have been linked to periods of cooler temperatures and visa versa. It has been theorized that mid-latitude winter storms are more severe when preceded by a geomagnetic storm and drought cycles appear to have a connection to the 22-year solar cycle (sunspot maximums in particular). These are all long-term effects. It is only in the technological age that it has begun to impact us in more immediate ways.
While the solar wind is always present and sends a constant stream of charged protons at the Earth, a solar storm throws out even more incredible amounts of energetic particles that flow at and past the Earth like a fast-moving river. This river of energy also brings out part of the sunís magnetic field with it, effectively “a magnetic cloud”. (The solar wind is what causes the background hiss you can often hear on a radio.) The Earth and its magnetic field act like a rock in the stream of the solar wind with a collision bulge sunward, the “bow wave”, and a slipstream “tail” on the opposite side.
When a solar storm occurs, contact between the magnetic cloud and the Earthís magnetic field creates an electrical current in the near vacuum of space that operates much like the electric generators we build ourselves. That explains why the telegraph ran without internal power for two hours back in 1859 and why power grids periodically crash in dramatic fashion.
Within the contact zones, along the lines of the Van Allen magnetic belts, charged particles excite atmospheric particles to the point of glowing and they are what make up the Aurora Borealis and Aurora Australis that glow in the night skies. Each element glows in a different color, for instance, oxygen glows green or red and nitrogen glows purple. Colors mix and blend and appear to fold within the electric field induced on either side of the auroral curtain by the electrons. Contrary to popular belief, auroras do not end when the sun rises, they simply can not compete with the light of the sun.
Auroras are actually present throughout the life of a geomagnetic storm and form an oval around the two magnetic poles. The bigger the magnetic storm, the farther south the Aurora Borealis extends and the farther north the Aurora Australis extends. There have been instances when auroras were reported as far south as northern Mexico and as far north as central Australia.
It is in out best interest to learn how to forecast solar events and we have a number of satellites in space to monitor the sun at all times. The National Science Foundation (NSF), National Aeronautics and Space Administration (NASA), the Departments of Commerce, Defense, Energy and Interior and National Oceanographic and Atmospheric Administration (NOAA) have combined to form the National Space Weather Program (NSWP).
It will one day be structured like the National Weather Service and provide timely, accurate, and reliable space environment observations, specifications and forecasts. We learn more about the sun every day and the importance of this knowledge grows by the hour. Solar forecasting becomes more and more crucial in todayís technological society and will become even more important as we reach beyond the Earth and colonize new worlds.
Written by Melody L. Higdon, 14 WS/DOPA