Facts of the Matter: Solar activity better studied but remains unpredictable

The sun is the source of all life and almost all energy on Earth, and we live within its extended atmosphere, protected only somewhat against its variable and harmful output of streams of high-energy particles and radiation by a weak magnetic field and our own thin atmosphere.

The sun is the subject of much current research. Geophysical methods similar to those that yield secrets about our own planet’s interior reveal features within the fluid body of the sun. Some of these appear to be related to sunspot maxima and minima.

The sun is a sphere of fluidlike plasma of hydrogen and helium ions with currents that are driven by thermonuclear temperatures of millions of degrees at its center.

Plasma is the fourth, high-temperature state of matter in which the internal energy is so high that electrical forces cannot hold electrons and atomic nuclei together as atoms. At the atomic scale it would resemble a soup of electrons with chunky hydrogen and helium ions drifting in it like peas in a thick broth.

Motion of the electrically charged plasma in intense convection currents creates magnetic effects that interact with the sun’s internal magnetic field. The rapid rotation of the sun on its axis twists the viscous plasma like taffy, causing magnetic fields that emerge from the surface to coil like springs. Every 11 years or so, after becoming increasingly chaotic with sunspot activity, the magnetic fields realign, and the activity gradually decreases until reaching solar minimum, followed soon by another cycle.

Each cycle and bit of data adds to the overall understanding of the sun’s climate; heliophysicists hope that will lead to better forecasts of solar weather events.

These events, such as magnetic storms that increase in frequency and intensify during solar maxima, can interfere with sensitive electronic circuits in Earth satellites and on the surface, causing disruptions, power outages and billions of dollars in damage.

Coronal mass ejections are huge blobs of charged particles that the sun emits like a planet-size burp. The mass of particles spreads outward from the sun to rain upon the solar system. If the ejection is aimed toward Earth, the disruptions can be serious even in times when overall solar activity is not so great.

Although we cannot prevent solar weather events, as with Earth weather the longer the forecast time, the greater the opportunity to monitor progress and make preparations.

New technology and techniques reveal plasma circulation patterns at and near the sun’s surface on a global scale that show some connection with the solar cycle. One is a meridional flow that changes speed as it travels across the surface from equator to poles.

Heliophysicists have followed the development of a solar jet stream from thousands of miles below the surface that seems to correspond in periodicity with the solar cycle. Others have detected acoustic oscillations that change with the solar cycle.

All of these are only preliminary findings, and caution is due against drawing any sweeping conclusions or harboring false expectations of accurate solar weather forecasts in the near future. Every step in understanding space weather and climate is one step in averting what could be a major disaster when the inevitable 200-year solar storm is imminent.

Richard Brill is a retired professor of science at Honolulu Community College. His column runs on the first and third Fridays of the month. Email questions and comments to brill@hawaii.edu.