Do Not Adjust Your Dial--Nor Blame the Phone Company
This October, inconspicuous notices appeared in some northern newspapers, warning of interruptions in telephone service. Pay-to-watch television subscribers received slightly more prominent warnings of service problems. All stated quite exactly the times of trouble, and all blamed the same cause: the sun.
Suspicious though northerners may be about the excuses of their service providers, in this instance the blame is well laid. During October, the sun now and again messed up our links to the rest of the world. It will do the same again toward spring: expect to see similar notices between late February and mid-March.
The basic explanation for the problem is that twice a year the sun is in a direct line between a satellite earth station and the particular geostationary satellite being received at that station. With our low sun angles, northerners are more likely than southerners to find the sun in the main beam of the receiving antenna. Now that we rely so greatly on satellites for communication, we must take the sun's position into careful account.
Since outages caused by the alignment of sun and satellites can be predicted accurately, that is the comparatively easy part. We must also consider the weather--on the sun. The light and heat produced by our neighborhood star are what we know best, but the sun radiates energy along most of the electromagnetic spectrum. X-rays, radio waves, ultraviolet emissions--the sun broadcasts prodigiously on all fronts. The electromagnetic waves vary in strength according to whether the sun is quiet or active. When it's active with flares and other disturbances, the sun's outer layers emit strong electromagnetic radiation and streams of very energetic particles.
Most communication systems have problems when the solar weather is extremely stormy and flares or other disturbances occur on the sun's surface so that ejected particles reach the vicinity of Earth. Enough energetic electrons and protons bashing the earth's magnetic field can deform it and warp the ionosphere. Wobbles in the ionosphere can put crazy bounces on radio communications that don't use satellites (once leading Fairbanks cab drivers to pick up calls sent by a dispatcher in Texas, to everybody's befuddlement).
As the particles and radio waves pour in, they can cause fadeouts in the signals from some of the geostationary communications satellites. Short wave radio circuits can experience outages; low-frequency navigational systems, including LORAN, and standard broadcast frequencies seem to lose strength. A big storm can even cause orbital shifts in navigational satellites.
The sun goes through an eleven-year weather cycle, and it's heading into its stormiest time. The peak in sunspots and solar flares for this cycle should arrive around the end of 1989. Thus we may be approaching a period when communications outages may be fairly common, and not very predictable.
This may be a winter to practice letter-writing skills. The good part of the sunspot story is that the magnetic storms produce auroras, so there'll be something to write about in those letters sent Outside.
