Cell phone users frustrated by a high incidence of dropped calls this summer can blame the sun for at least some of their lost signals. According to a new research study slated for publication in the next issue of the Proceedings of the Institute of Electrical and Electronics Engineers (IEEE), solar flares cause some of the annoying conversation breakers.
Led by Queens University mathematics professor Dr. David Thomson, the study concludes that many of the dropped connections -- which in the past were attributed to atmospheric disturbances and other terrestrial phenomena -- are actually being caused by solar disturbances on the surface of the sun.
An Odd Solar Connection
"You always expect some calls to be dropped, like when you get into an elevator and the doors close, or when you are standing out in the street and suddenly a tractor trailer parks right between you and the cell site," Dr. Thomson explained in our interview. "But, when we looked at the dropping problem, we found an odd solar connection to the dropped call rates."
The sun became a major suspect when researchers discovered that cell phone users typically experience more dropped calls in the summertime than they do during the winter months. "We see dropped call rates, depending on the system and where you are, of about 2 percent of the calls in summertime, and then in winter this drops down to 0.5 or 0.6 percent in the northern states of the Midwest," Thomson said.
"Of course, all this depends on the overall structure of the cellular network," Thomson noted. "When you get into rural areas where the cell phone sites are sparse and coverage is not good enough to begin with, performance can get pretty bad, with 5 to 7 percent of the calls being dropped."
The solar effects that the researchers attribute to cell call outages proved to be identical to the ones that scientists previously had measured using the solar wind and solar radio instruments onboard NASA's Ulysses spacecraft, which was launched in 1990. "We have been observing very characteristic frequencies on Ulysses that seem to be linked to solar activity and we see the same frequencies being linked to cell phone drops," Thomson said.
Whenever the sun's magnetic energy becomes unstable and collapses, it causes vast amounts of gas to become explosively heated. The phenomenon, called a solar flare, releases intense waves of electromagnetic energy that radiate into space.
Unraveling the Mystery
Once these waves reach the earth, much of the electrical charge is absorbed by a segment of the atmosphere called the ionosphere. As every amateur radio operator already knows, the ionosphere also causes short-wave radio transmissions to be reflected back down to earth, traveling hundreds or even thousands of miles in the process.
Given that the ionosphere absorbs much of the sun's electromagnetic energy, there is question as to why it doesn't protect cellular calls from interruptions. Thomson says this is a mystery that has yet to be unraveled.
"We know the sun is affecting cell phone calls but we don't know how," Thomson admitted, while indicating that the ultimate answer may have to do with how the sun's energy interacts with the ionosphere. What Thomson did say with more certainty was that the rise in dropped calls has to do with the tilt of the earth's axis towards the sun during summer in the northern hemisphere.
Though the study's results are very different from the explanations that appear in most engineering textbooks, the researchers point out that that sun undergoes more than 10 million normal modes of activity and that understanding their interactions with engineering systems on Earth is a challenge that scientists are only beginning to tackle.
"While many of the studies on telecommunications and cell phone system failures arose between the 1970s and the 1990s, it's now timely to generate a synthesis of this knowledge and apply it to the problems that prompted the research in the first place," Thomson added.