New cycle of solar activity

MOSCOW. (Yury Zaitsev for RIA Novosti) - Space-based solar observatories have recently registered an area with an enhanced magnetic field on the surface of the Sun. This is a sure sign that the Sun has entered its 24th activity cycle. This event will bring no good to the Earth residents.

Wars, revolutions, cultural, scientific, and technical breakthroughs, the suicide rate, calamities and man-made disasters are all associated with the Sun's activity. Understanding the nature of this interaction and forecasting solar activity levels is an urgent task for modern science.

Small and short splashes of magnetic activity with a reverse magnetic field were registered last August. But apparently, this was a sporadic prelude to a new cycle against the backdrop of the minimal activity of the outgoing one.

Scientists began to assign numbers to solar cycles 250 years ago, when they started regular observations of the number of spots on the Sun's visible disc.

There are very few sunspots in the beginning of a cycle. Over several years, their number grows to a certain maximum, and then slowly drops back down to the minimum. Hence, a period when the number of sunspots is the biggest is called the solar maximum of a cycle, and when there are almost none, the solar minimum. The alternation of maximums and minimums takes place in 11 years on average. This is why it is called the 11-year sun cycle.

During the past 80 years, the flow of the cycles speeded up a bit, and their average duration has gone down to about 10 and a half years. Obviously, the Sun has some inner clock, which sets the duration of each particular cycle, but scientists do not yet know how it works.

Maximums and minimums of activity may affect the climate. In the latter half of the 17th century, solar activity was very weak. Average annual temperatures in Europe dropped considerably, signaling the beginning of a minor ice age. This was probably caused by a reduced solar impact on the Earth's climate.

Today, solar activity is the highest it has been in the last thousand years. In the previous century, the number of sunspots increased many times over. At the same time, in the last few years the climate has become much warmer by geological measures. It is quite possible that anthropogenic pollution of the environment is making a contribution to this process. But many scientists believe that global climate change is primarily linked with solar activity.

The previous, 23rd cycle was abnormally intensive. A solar flare on October 23, 2003 was the most powerful one during the entire history of observations. The monitoring instruments went off the charts, and scientists failed to precisely measure the huge amount of energy released.

Luckily, the flare occurred at the edge of the solar halo. If such a burst takes place in the center of the solar disc, it may trigger serious consequences which are difficult to predict.

Recently, extraordinary events have also been taking place on Jupiter. For the first time in the history of observations, a second mysterious red spot has appeared on its surface. The period of the Jupiter revolution around the Sun is very similar in its duration to the 11-year cycles of solar activity, and there may be a link between the processes taking place in the Sun and on the biggest planet of our solar system.

As for Earth, the empiric connection between solar activity and most diverse processes on our planet has long been revealed. A number of phenomena linked with the impact of solar corpuscular and electromagnetic radiation on the geomagnetic, atmospheric, biological and other processes on Earth are a subject of the branch of science called solar-terrestrial relationships. Leading Russian scientists Vladimir Vernadsky, Konstantin Tsiolkovsky, and Alexander Chizhevsky laid this branch's foundation in the early 20th century.

An increase in the intensity of solar wind - a flow of plasma of the solar corona that abruptly rises with the growth of solar activity - does not only cause the Aurora Borealis, but also disturbances in the magnetic field. Magnetic storms, in turn, can cause accidents in communication and power lines, and oil and gas pipelines; they directly affect physical and mental health.

Scientists are not yet able to predict the intensity of the new solar cycle or the start of its maximum. Some of them believe that the number of sunspots will reach 140 during the cycle's maximum in October 2011; others predict that there will be no more than 90 sunspots by August 2012. It will be possible to confirm or refute these forecasts a year after the maximum has passed. If solar activity rapidly intensifies, the maximum should be more powerful and take place faster than in case of a slow rise. In other words, if the maximum takes place in 2011, it will be accompanied by very high solar activity.

According to tentative estimates, the new cycle will be 30% to 50% more powerful than the previous one that was accompanied by a number of serious cataclysms.

Scientists published forecasts of solar activity only twice - in 1989 and 1996. Their forecasts were largely confirmed.

Yury Zaitsev is an expert at the Institute of Space Research of the Russian Academy of Sciences.

The opinions expressed in this article are the author's and do not necessarily represent those of RIA Novosti.

To participate in the discussion
log in or register
Заголовок открываемого материала