What to know about the solar cycle

November 1, 2011 11:23

Eleven years in the life of the Sun.

First spot on the Sun was seen in 1611. This shocked the scientific world, who thought the perfect light and unchanged.

Soon the media view of the sun was completely destroyed: it turned out that the spots also change — increased or decreased during the cycle, which lasts from eight to fourteen years of age (most often — eleven).

The more sunspots, the more solar activity — mostly coronary mass ejections. One cycle is very different from the intensity of the other. Solar maxima can be so weak that they are almost impossible to distinguish from the previous low.

That is what happened in the years 1645-1715 (the Maunder minimum). Astronomers are still able to track the number of cycles of sunspots, but their number has dropped significantly. There were even thirty years, when scientists counted only thirty spots — one thousandth of the normal amount.

The average annual number of sunspots (here and below the image NASA)

Maunder Minimum coincided with the so-called small ice age: there were unusually cold weather, even frozen Thames and the Baltic Sea. This period was longer than the Maunder minimum, which indicates the presence of some other factors, but still the main, most scientists believed it reduced solar activity.

The causes of the solar cycle was beginning to understand the science in the first half of XX century. The researchers found that the spots are magnetic in nature and that the sun magnetized just as banal bar magnet. The difference is that, unlike the latter, the interior of the Sun is in constant motion.

By tracking sound waves that pass through the center of the Sun, helioseismology found that the magnetic material inside the sun is constantly stretched, twisted and crossed, rising to the surface. Accurate picture of the movement is not yet clear, but it is clear: over time it leads to the fact that the poles are reversed.

This happens about once every eleven years. Thus, a complete solar cycle covers about twenty-two years, but the Sun behaves the same regardless of which pole is at the "top", so the 11-year cycle is more famous.

Today, the light moves to the maximum, so the flare and coronal mass ejections occur more often than a few years ago. The peak is reached at the end of 2013 or early 2014, and the minimum is expected in 2020, although the predictions concerning the solar cycle is not different accuracy. This is the first cycle, which mankind have relatively complete data, and it turned out to be the slowest since the beginning of the space age.

The slower than expected development cycle has led some researchers to the assumption that the following may give a small number of spots in the solar maximum. It is too early to say for sure, but even if that happens, no reason to worry. Four hundred years of observations have shown that the loop in the end always comes back to normal.

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