Violent Storms on the Sun Expected to Peak in 1989

A period of violent storms on the surface of the sun is expected to build into one of the most active periods of solar activity in hundreds of years and now may peak earlier than had been expected, possibly by the end of next year.

Scientists attending the fall meeting of the American Geophysical Union here this week said that solar cycles, which peak every 11 years, can disrupt communications and even cause satellites to tend to fall out of the sky during the period of maximum solar activity.

Even though this should be one of the most active periods ever recorded, the phenomenon will most likely manifest itself chiefly in static on radios and dramatic presentations of the Northern and Southern Lights.

Intense Activity

Kenneth H. Schatten of NASA’s Goddard Space Flight Center in Greenbelt, Md., said he had initially expected the current cycle to peak sometime in 1990, and possibly as late as 1991, but he has revised that because the current level of solar activity is so intense that the cycle appears to be building toward an earlier climax, probably in late 1989.

While some scientists have predicted that this will be the most intense cycle ever recorded, Schatten said he thinks it will fall a little short of the record holder--1959.

The period is characterized by violent storms on the surface of the sun as large concentrations of “sun spots” migrate across its surface.

The storms release intense bursts of energy that bombard the Earth in various ways. One result is that ultraviolet radiation heats the earth’s upper atmosphere, which causes air to expand and rise to higher altitudes. That creates an atmospheric drag on satellites that reduces their life span.

Some forms of radiation can be so intense that it would be deadly to an astronaut on the surface of the moon, which does not have Earth’s protective atmosphere, said Ron Zwickl, a space physicist with the National Oceanic and Atmospheric Administration. And it does not even have to be during a period of maximum activity.

A solar storm in August of 1972 released a burst of radiation “that would have been a lethal dose” to anyone on the moon, Zwickl said.

Sometimes, the solar activity can be considerably less lethal, but intensely annoying, he added.

Solar storms can wreak havoc on telecommunications signals, and a few years ago a command to a satellite was scrambled. The distorted message told the satellite to fold its solar panels from which it got the electricity needed to charge its batteries, Zwickl said. The satellite did what the scrambled message told it to do, and its batteries died.

“The result was we lost the satellite,” he added.

To Study Closely

Scientists around the world will be studying the sun closely during this period, hoping to learn much about dynamics that cause such things as variations in solar activity.

Meteorologists will be paying particularly close attention. Many assume that storms on the sun have some direct effect on weather on the Earth. But no one, so far, has been able to prove that.

The current 11-year cycle reached its lowest point--when the sun was in its least-active phase--in 1986. Earlier this year the activity began increasing rapidly, outstripping all earlier cycles during the first few months. After it peaks around the end of next year, activity will drop off quickly and continue to decline for the rest of the 11-year period. Then the entire process will repeat itself.

But next time, it may not be quite as dramatic.