Why take the spot on the sun?

Why take the spot on the sun? Before answering this question, first ask - what are these spots?

For mankind in all ages of its existence the sun was the main celestial bodies, which gives Earth life, light, heat. And at the same time the sun - the source of hundreds of questions.

At first glance, the Sun - blindingly bright light ball. In colloquial speech often used speed "clear sun", "pure as the sun.

But in 1613, Galileo Galilei, Italian physicist, mathematician and astronomer, published his famous letter, which speaks of sunspots, as a result of observations with application of his telescope. And from that time began, though not always systematically recorded spots on the sun.

Galileo's observations disproved the common view of perfection of the sun. And it borders on heresy. It can be questioned, and in God, and divine power of kings.

Nevertheless, observations have confirmed. And the sun to see the very bright, very clean, very perfect disks can spot! Sometimes they can even be seen with the naked eye when the sun is low in the sky. What are they, why there, as they affect life on Earth - an explanation very much.

These dark formations on the solar disk is still largely remain a mystery. In a telescope can see that they have a complex structure.

The spots are different - from "small" diameter "only" 1000-2000 km, to the giant, exceeding the size of our Earth. The largest spot diameter of 100,000 miles recorded in 1995, the solar observatory SOHO. Think about it, it's more than seven times the diameter of Earth.

The spots often form groups of several large and small spots. The picture of all the time, the spots are born, grow, decay, disappear. Live spot is relatively long, sometimes 2-3 turns of the Sun (solar rotation period of approximately 27 Earth days).

Sunspots are caused by powerful magnetic fields that arise inside the Sun. These fields impede the movement of the plasma, slowing its convection, which weakens the power supply from the depths of the Sun. Therefore, the temperature in the spots on the 1000-1500 K lower than around, and they seem dark, even though their real color - red. Most stains occur in the equatorial zone of the Sun, their shape, size and number is constantly changing.

To answer the questions related to the Sun system was established observations - the so-called office of the Sun, which brings together virtually all the large observatories of the Earth, as well as special plant. The main objective of the service was registration of dark sunspots and solar flares.

The combined effect of events on the surface of the Sun called solar activity. It's dark spots, flares, torches, and prominences. The more of these phenomena, the greater the solar activity.

It turned out that earthlings manifestations of solar activity are very important. And just important, they must somehow express quantitatively.

To estimate the solar Swiss astronomer Wolf introduced a simple method which is based on counting the number of sunspots: W = 10g f, where W - the index of solar activity, g - the number of sunspot groups, f - the total number of spots.