Observations of the Sun which are conducted since 2002 by means of the specialized orbital Rhessi telescope constantly lead to the new opening often contradicting results of the previous observations.
The first observations of a form of the Sun allowed to establish that it is changeable and changes depending on activity of a star. Also astronomers of NASA defined that the surface of the solar sphere not equal, and is covered with numerous ledges in the form of crests. The above the activity of the Sun grows, the concentration of these crests in the equatorial area of a star is closer. Because of it its form becomes a little flattened from poles.
It is also established that these roughnesses have the magnetic nature. The convective cells rising from the center of the Sun are formed in supergranules, approaching is closer to its surface. On a surface of a supergranule are shown in the form of characteristic ledges. This phenomenon to similarly rising bubbles in the boiling water, only occurs in star scales. Diameter of supergranules is 20-30 thousand kilometers, and life cycle – up to two days. Changes in the equatorial radius to which they lead are measured in degrees and calculated as follows. Extreme points of a visible disk of a star connect to a point of location of the observer. The corner between the beams which are released from extreme points is called the visible radius of the Sun. And so, the established changes in a form of a star are 10.77 angular milliseconds. It is about 1/360 from one degree. In other words, the thickening of the Sun seen to us correspond to the visible thickness of a human hair. However even such in appearance insignificant fluctuations have notable impact on gravitational field of the Sun.
However the last researches showed that the flattened form of the only star in the solar system does not depend on roughnesses of its surface. The difference between the equatorial diameter and diameter measured between poles is insignificant, but nevertheless is. And the reason for that – the gravitation, rotation, magnetic field and streams of plasma passing in a star. At the same time the form close to an ideal sphere is quite stable and does not depend on activity of the Sun. These results were received by scientists of the University of Hawaii on the basis of measurements of Observatory of Solar dynamics. More and more early researches of a form of the Sun had different results on the reason of atmospheric distortions of the received images. The new view, according to scientists, can have serious impact on understanding of the processes happening in it on a form of the Sun. Quite perhaps, it is necessary to revise completely theories of internal dynamics of plasma of the Sun.