How Big Is The Sun Depends On How Active It Is, A 21-Year-Long Study Shows


How big is the Sun? The answer to this question depends from one period to another because the Sun’s size is influenced by its magnetic activity. Therefore, during periods of high activity, the dimensions of the Sun decrease between 1 and 2 kilometers. That is the surprising result obtained by Alexander Kosovichev, from the New Jersey Institute of Technology in Newark, in the United States, and Jean-Pierre Rozelot from the University of Cote d’Azur, in Nice, in France.

The two scientists followed the Sun’s activity for 21 years using the NASA’s Solar Dynamics Observatory (SDO) and the well-known ESA’s SOHO (Solar and Heliospheric Observatory).

Solar magnetic storms influence how big is the sun

Variations of 1 or 2 kilometers are entirely negligible when compared to the 695,700 kilometers that the Sun’s radius measures, but it is still necessary to understand the source of this difference.

According to the scientists, the magnetic activity of our star reaches its maximum once every 11 years. During this maximum, the Sun emits streams of charged particles into space which some of them reach the Earth causing what we call solar storms, phenomena that sometimes disrupt communications or causes power losses.

This small variation in Sun’s radius is probably linked to mechanisms that are still poorly understood and trigger a new cycle, the scientists involved in the study agree.

It was difficult to measure a ball of gases, that is the Sun

Such an exact measurement was difficult to obtain since, unlike rocky planets such as Earth, Mars or Venus, which have a well-defined rocky surface, the Sun, which can be described roughly as a ball of gases, do not have a solid surface. It’s a collapsing mass of gas.

Because of this difficulty, astronomers have exploited the speed data of seismic waves propagating inside the Sun. However, the slightest swelling or tightening changes the frequency of these waves.

According to the two researchers, this variation is due to the installation of a vertical magnetic field during periods of solar activity. The scientists concluded that how big is the Sun depends on our star’s period of activity.


Related Posts